RFC patchcheckout: print something when checking out paths

> @@ -371,17 +374,27 @@ static int checkout_paths(const struct checkout_opts *opts,
>  		struct cache_entry *ce = active_cache[pos];
>  		if (ce->ce_flags & CE_MATCHED) {
>  			if (!ce_stage(ce)) {
> -				errs |= checkout_entry(ce, &state, NULL);
> +				errs |= checkout_entry(ce, &state,
> +						       NULL, &nr_checkouts);
>  				continue;

>  			}
>  			if (opts->writeout_stage)
> -				errs |= checkout_stage(opts->writeout_stage, ce, pos, &state);
> +				errs |= checkout_stage(opts->writeout_stage,
> +						       ce, pos,
> +						       &state, &nr_checkouts);

>  			pos = skip_same_name(ce, pos) - 1;
>  		}
>  	}
> -	errs |= finish_delayed_checkout(&state);
> +	errs |= finish_delayed_checkout(&state, &nr_checkouts);
> +
> +	if (opts->count_checkout_paths)
> +		fprintf_ln(stderr, Q_("%d path has been updated",
> +				      "%d paths have been updated",
> +				      nr_checkouts),
> +			   nr_checkouts);

> @@ -1064,6 +1077,7 @@ static int parse_branchname_arg(int argc, const char **argv,
>  		has_dash_dash = 1; /* case (3) or (1) */
>  	else if (dash_dash_pos >= 2)
>  		die(_("only one reference expected, %d given."), dash_dash_pos);
> +	opts->count_checkout_paths = !opts->quiet && !has_dash_dash;

>
> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
>
> > Since the purpose of printing this is to help disambiguate. Only do it
> > when "--" is missing (the actual reason though is many tests check
> > empty stderr to see that no error is raised and I'm too lazy to fix
> > all the test cases).
>
> Heh, honesty is good but in this particular case the official reason
> alone would make perfect sense, too ;-)
>
> As with progress output, shouldn't this automatically be turned off
> when the standard error stream goes to non tty, as the real purpose
> of printing is to help the user sitting in front of the terminal and
> interacting with the command?

> > @@ -371,17 +374,27 @@ static int checkout_paths(const struct checkout_opts *opts,
> >               struct cache_entry *ce = active_cache[pos];
> >               if (ce->ce_flags & CE_MATCHED) {
> >                       if (!ce_stage(ce)) {
> > -                             errs |= checkout_entry(ce, &state, NULL);
> > +                             errs |= checkout_entry(ce, &state,
> > +                                                    NULL, &nr_checkouts);
> >                               continue;
>
> As we count inside checkout_entry(), we might not actually write
> this out when we know that the working tree file is up to date
> already but we do not increment in that case either, so we keep
> track of the accurate count of "updates", not path matches (i.e. we
> are not reporting "we made sure this many paths are up to date in
> the working tree"; instead we are reporting how many paths we needed
> to overwrite in the working tree).

> >                       pos = skip_same_name(ce, pos) - 1;
> >               }
> >       }
> > -     errs |= finish_delayed_checkout(&state);
> > +     errs |= finish_delayed_checkout(&state, &nr_checkouts);
> > +
> > +     if (opts->count_checkout_paths)
> > +             fprintf_ln(stderr, Q_("%d path has been updated",
> > +                                   "%d paths have been updated",
> > +                                   nr_checkouts),
> > +                        nr_checkouts);
>
> This one may want to be protected behind isatty(2).  Or the default
> value of count_checkout_paths could be tweakedbased on isatty(2).

> Another thing I'm going to change (if this v1 is in the right
> direction): print different messages for "git checkout -- foo" and
> "git checkout foo -- bar". The first one is "%d paths have been
> reverted" but the second one does different things and probably should
> say "%d paths have been updated from branch foo" or something like
> that.

> On Mon, Nov 12, 2018 at 7:21 AM Junio C Hamano <gitster@pobox.com> wrote:
>>
>> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
>>
>> > Since the purpose of printing this is to help disambiguate. Only do it
>> > when "--" is missing (the actual reason though is many tests check
>> > empty stderr to see that no error is raised and I'm too lazy to fix
>> > all the test cases).
>>
>> Heh, honesty is good but in this particular case the official reason
>> alone would make perfect sense, too ;-)
>>
>> As with progress output, shouldn't this automatically be turned off
>> when the standard error stream goes to non tty, as the real purpose
>> of printing is to help the user sitting in front of the terminal and
>> interacting with the command?
>
> I see this at the same level as "Switched to branch 'foo'" which is
> also protected by opts->quiet. If we start hiding messages based on
> tty it should be done for other messages in update_refs_for_switch()
> too, I guess?

>
>
> On Mon, Nov 12 2018, Duy Nguyen wrote:
>
> > On Mon, Nov 12, 2018 at 7:21 AM Junio C Hamano <gitster@pobox.com> wrote:
> >>
> >> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
> >>
> >> > Since the purpose of printing this is to help disambiguate. Only do it
> >> > when "--" is missing (the actual reason though is many tests check
> >> > empty stderr to see that no error is raised and I'm too lazy to fix
> >> > all the test cases).
> >>
> >> Heh, honesty is good but in this particular case the official reason
> >> alone would make perfect sense, too ;-)
> >>
> >> As with progress output, shouldn't this automatically be turned off
> >> when the standard error stream goes to non tty, as the real purpose
> >> of printing is to help the user sitting in front of the terminal and
> >> interacting with the command?
> >
> > I see this at the same level as "Switched to branch 'foo'" which is
> > also protected by opts->quiet. If we start hiding messages based on
> > tty it should be done for other messages in update_refs_for_switch()
> > too, I guess?
>
> I have no real opinion either way, but whatever we can do about
> "checkout" being so confusing since it does so many things is most
> welcome.
>
> Just an alternative: Maybe we can start this out as advice() output
> that's either opt-in via config (not on by default) to start with, or
> have some advice_tty() that only emits it in the same circumstances we
> emit the progress output?

>> > I see this at the same level as "Switched to branch 'foo'" which is
>> > also protected by opts->quiet. If we start hiding messages based on
>> > tty it should be done for other messages in update_refs_for_switch()
>> > too, I guess?
>
> No let's drop this for now. I promise to come back with something
> better (at least it still sounds better in my mind). If that idea does
> not work out, we can come back and see if we can improve this.

> On Mon, Nov 19, 2018 at 04:19:53PM +0100, Duy Nguyen wrote:
> > I promise to come back with something better (at least it still
> > sounds better in my mind). If that idea does not work out, we can
> > come back and see if we can improve this.
> 
> So this is it. The patch isn't pretty, mostly as a proof of
> concept. Just look at the three functions at the bottom of checkout.c,
> which is the main thing.
> 
> This patch tries to split "git checkout" command in two new ones:
> 
> - git switch-branch is all about switching branches
> - git restore-paths (maybe restore-file is better) for checking out
>   paths
> 
> The main idea is these two commands will co-exist with the good old
> 'git checkout', which will NOT be deprecated. Old timers will still
> use "git checkout". But new people should be introduced to the new two
> instead. And the new ones are just as capable as "git checkout".
> 
> Since the three commands will co-exist (with duplicate functionality),
> maintenance cost must be kept to minimum. The way I did this is simply
> split the command line options into three pieces: common,
> switch-branch and checkout-paths. "git checkout" has all three, the
> other two have common and another piece.
>
> With this, a new option added to git checkout will be automatically
> available in either switch-branch or checkout-paths. Bug fixes apply
> to all relevant commands.
> 
> Later on, we could start to add a bit more stuff in, e.g. some form of
> disambiguation is no longer needed when running as switch-branch, or
> restore-paths.
> 
> So, what do you think?

> -- 8< --
> diff --git a/builtin.h b/builtin.h
> index 6538932e99..6e321ec8a4 100644
> --- a/builtin.h
> +++ b/builtin.h
> @@ -214,6 +214,7 @@ extern int cmd_remote_fd(int argc, const char **argv, const char *prefix);
>  extern int cmd_repack(int argc, const char **argv, const char *prefix);
>  extern int cmd_rerere(int argc, const char **argv, const char *prefix);
>  extern int cmd_reset(int argc, const char **argv, const char *prefix);
> +extern int cmd_restore_paths(int argc, const char **argv, const char *prefix);
>  extern int cmd_rev_list(int argc, const char **argv, const char *prefix);
>  extern int cmd_rev_parse(int argc, const char **argv, const char *prefix);
>  extern int cmd_revert(int argc, const char **argv, const char *prefix);
> @@ -227,6 +228,7 @@ extern int cmd_show_index(int argc, const char **argv, const char *prefix);
>  extern int cmd_status(int argc, const char **argv, const char *prefix);
>  extern int cmd_stripspace(int argc, const char **argv, const char *prefix);
>  extern int cmd_submodule__helper(int argc, const char **argv, const char *prefix);
> +extern int cmd_switch_branch(int argc, const char **argv, const char *prefix);
>  extern int cmd_symbolic_ref(int argc, const char **argv, const char *prefix);
>  extern int cmd_tag(int argc, const char **argv, const char *prefix);
>  extern int cmd_tar_tree(int argc, const char **argv, const char *prefix);
> diff --git a/builtin/checkout.c b/builtin/checkout.c
> index acdafc6e4c..868ca3c223 100644
> --- a/builtin/checkout.c
> +++ b/builtin/checkout.c
> @@ -33,6 +33,16 @@ static const char * const checkout_usage[] = {
>  	NULL,
>  };
>  
> +static const char * const switch_branch_usage[] = {
> +	N_("git switch-branch [<options>] <branch>"),
> +	NULL,
> +};
> +
> +static const char * const restore_paths_usage[] = {
> +	N_("git restore-paths [<options>] [<branch>] -- <file>..."),
> +	NULL,
> +};
> +
>  struct checkout_opts {
>  	int patch_mode;
>  	int quiet;
> @@ -44,6 +54,7 @@ struct checkout_opts {
>  	int ignore_skipworktree;
>  	int ignore_other_worktrees;
>  	int show_progress;
> +	int dwim_new_local_branch;
>  	/*
>  	 * If new checkout options are added, skip_merge_working_tree
>  	 * should be updated accordingly.
> @@ -55,6 +66,7 @@ struct checkout_opts {
>  	int new_branch_log;
>  	enum branch_track track;
>  	struct diff_options diff_options;
> +	char *conflict_style;
>  
>  	int branch_exists;
>  	const char *prefix;
> @@ -1223,78 +1235,105 @@ static int checkout_branch(struct checkout_opts *opts,
>  	return switch_branches(opts, new_branch_info);
>  }
>  
> -int cmd_checkout(int argc, const char **argv, const char *prefix)
> +static struct option *add_common_options(struct checkout_opts *opts,
> +					 struct option *prevopts)
>  {
> -	struct checkout_opts opts;
> -	struct branch_info new_branch_info;
> -	char *conflict_style = NULL;
> -	int dwim_new_local_branch = 1;
> -	int dwim_remotes_matched = 0;
>  	struct option options[] = {
> -		OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
> -		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
> +		OPT__QUIET(&opts->quiet, N_("suppress progress reporting")),
> +		OPT_BOOL(0, "ignore-skip-worktree-bits", &opts->ignore_skipworktree,
> +			 N_("do not limit pathspecs to sparse entries only")),
> +		{ OPTION_CALLBACK, 0, "recurse-submodules", NULL,
> +			    "checkout", "control recursive updating of submodules",
> +			    PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
> +		OPT_BOOL(0, "progress", &opts->show_progress, N_("force progress reporting")),
> +		OPT__FORCE(&opts->force, N_("force checkout (throw away local modifications)"),
> +			   PARSE_OPT_NOCOMPLETE),
> +		OPT_STRING(0, "conflict", &opts->conflict_style, N_("style"),
> +			   N_("conflict style (merge or diff3)")),
> +		OPT_END()
> +	};
> +	struct option *newopts = parse_options_concat(prevopts, options);
> +	free(prevopts);
> +	return newopts;
> +}
> +
> +static struct option *add_switch_branch_options(struct checkout_opts *opts,
> +						struct option *prevopts)
> +{
> +	struct option options[] = {
> +		OPT_STRING('b', NULL, &opts->new_branch, N_("branch"),
>  			   N_("create and checkout a new branch")),
> -		OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
> +		OPT_STRING('B', NULL, &opts->new_branch_force, N_("branch"),
>  			   N_("create/reset and checkout a branch")),
> -		OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
> -		OPT_BOOL(0, "detach", &opts.force_detach, N_("detach HEAD at named commit")),
> -		OPT_SET_INT('t', "track",  &opts.track, N_("set upstream info for new branch"),
> +		OPT_BOOL('l', NULL, &opts->new_branch_log, N_("create reflog for new branch")),
> +		OPT_BOOL(0, "detach", &opts->force_detach, N_("detach HEAD at named commit")),
> +		OPT_SET_INT('t', "track",  &opts->track, N_("set upstream info for new branch"),
>  			BRANCH_TRACK_EXPLICIT),
> -		OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
> -		OPT_SET_INT_F('2', "ours", &opts.writeout_stage,
> +		OPT_STRING(0, "orphan", &opts->new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
> +		OPT_BOOL('m', "merge", &opts->merge, N_("perform a 3-way merge with the new branch")),
> +		OPT_HIDDEN_BOOL(0, "guess", &opts->dwim_new_local_branch,
> +				N_("second guess 'git checkout <no-such-branch>'")),
> +		OPT_BOOL(0, "ignore-other-worktrees", &opts->ignore_other_worktrees,
> +			 N_("do not check if another worktree is holding the given ref")),
> +		OPT_END()
> +	};
> +	struct option *newopts = parse_options_concat(prevopts, options);
> +	free(prevopts);
> +	return newopts;
> +}
> +
> +static struct option *add_checkout_path_options(struct checkout_opts *opts,
> +						struct option *prevopts)
> +{
> +	struct option options[] = {
> +		OPT_SET_INT_F('2', "ours", &opts->writeout_stage,
>  			      N_("checkout our version for unmerged files"),
>  			      2, PARSE_OPT_NONEG),
> -		OPT_SET_INT_F('3', "theirs", &opts.writeout_stage,
> +		OPT_SET_INT_F('3', "theirs", &opts->writeout_stage,
>  			      N_("checkout their version for unmerged files"),
>  			      3, PARSE_OPT_NONEG),
> -		OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)"),
> -			   PARSE_OPT_NOCOMPLETE),
> -		OPT_BOOL('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
> -		OPT_BOOL_F(0, "overwrite-ignore", &opts.overwrite_ignore,
> -			   N_("update ignored files (default)"),
> -			   PARSE_OPT_NOCOMPLETE),
> -		OPT_STRING(0, "conflict", &conflict_style, N_("style"),
> -			   N_("conflict style (merge or diff3)")),
> -		OPT_BOOL('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
> -		OPT_BOOL(0, "ignore-skip-worktree-bits", &opts.ignore_skipworktree,
> -			 N_("do not limit pathspecs to sparse entries only")),
> -		OPT_HIDDEN_BOOL(0, "guess", &dwim_new_local_branch,
> -				N_("second guess 'git checkout <no-such-branch>'")),
> -		OPT_BOOL(0, "ignore-other-worktrees", &opts.ignore_other_worktrees,
> -			 N_("do not check if another worktree is holding the given ref")),
> -		{ OPTION_CALLBACK, 0, "recurse-submodules", NULL,
> -			    "checkout", "control recursive updating of submodules",
> -			    PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
> -		OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
> -		OPT_END(),
> +		OPT_BOOL('p', "patch", &opts->patch_mode, N_("select hunks interactively")),
> +		OPT_END()
>  	};
> +	struct option *newopts = parse_options_concat(prevopts, options);
> +	free(prevopts);
> +	return newopts;
> +}
>  
> -	memset(&opts, 0, sizeof(opts));
> +static int checkout_main(int argc, const char **argv, const char *prefix,
> +			 struct checkout_opts *opts, struct option *options,
> +			 const char * const usagestr[])
> +{
> +	struct branch_info new_branch_info;
> +	int dwim_remotes_matched = 0;
> +
> +	memset(opts, 0, sizeof(*opts));
> +	opts->dwim_new_local_branch = 1;
>  	memset(&new_branch_info, 0, sizeof(new_branch_info));
> -	opts.overwrite_ignore = 1;
> -	opts.prefix = prefix;
> -	opts.show_progress = -1;
> +	opts->overwrite_ignore = 1;
> +	opts->prefix = prefix;
> +	opts->show_progress = -1;
>  
> -	git_config(git_checkout_config, &opts);
> +	git_config(git_checkout_config, opts);
>  
> -	opts.track = BRANCH_TRACK_UNSPECIFIED;
> +	opts->track = BRANCH_TRACK_UNSPECIFIED;
>  
> -	argc = parse_options(argc, argv, prefix, options, checkout_usage,
> +	argc = parse_options(argc, argv, prefix, options, usagestr,
>  			     PARSE_OPT_KEEP_DASHDASH);
>  
> -	if (opts.show_progress < 0) {
> -		if (opts.quiet)
> -			opts.show_progress = 0;
> +	if (opts->show_progress < 0) {
> +		if (opts->quiet)
> +			opts->show_progress = 0;
>  		else
> -			opts.show_progress = isatty(2);
> +			opts->show_progress = isatty(2);
>  	}
>  
> -	if (conflict_style) {
> -		opts.merge = 1; /* implied */
> -		git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
> +	if (opts->conflict_style) {
> +		opts->merge = 1; /* implied */
> +		git_xmerge_config("merge.conflictstyle", opts->conflict_style, NULL);
>  	}
>  
> -	if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
> +	if ((!!opts->new_branch + !!opts->new_branch_force + !!opts->new_orphan_branch) > 1)
>  		die(_("-b, -B and --orphan are mutually exclusive"));
>  
>  	/*
> @@ -1302,14 +1341,14 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
>  	 * and new_branch_force and new_orphan_branch will tell us which one of
>  	 * -b/-B/--orphan is being used.
>  	 */
> -	if (opts.new_branch_force)
> -		opts.new_branch = opts.new_branch_force;
> +	if (opts->new_branch_force)
> +		opts->new_branch = opts->new_branch_force;
>  
> -	if (opts.new_orphan_branch)
> -		opts.new_branch = opts.new_orphan_branch;
> +	if (opts->new_orphan_branch)
> +		opts->new_branch = opts->new_orphan_branch;
>  
>  	/* --track without -b/-B/--orphan should DWIM */
> -	if (opts.track != BRANCH_TRACK_UNSPECIFIED && !opts.new_branch) {
> +	if (opts->track != BRANCH_TRACK_UNSPECIFIED && !opts->new_branch) {
>  		const char *argv0 = argv[0];
>  		if (!argc || !strcmp(argv0, "--"))
>  			die(_("--track needs a branch name"));
> @@ -1318,7 +1357,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
>  		argv0 = strchr(argv0, '/');
>  		if (!argv0 || !argv0[1])
>  			die(_("missing branch name; try -b"));
> -		opts.new_branch = argv0 + 1;
> +		opts->new_branch = argv0 + 1;
>  	}
>  
>  	/*
> @@ -1337,56 +1376,56 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
>  	if (argc) {
>  		struct object_id rev;
>  		int dwim_ok =
> -			!opts.patch_mode &&
> -			dwim_new_local_branch &&
> -			opts.track == BRANCH_TRACK_UNSPECIFIED &&
> -			!opts.new_branch;
> +			!opts->patch_mode &&
> +			opts->dwim_new_local_branch &&
> +			opts->track == BRANCH_TRACK_UNSPECIFIED &&
> +			!opts->new_branch;
>  		int n = parse_branchname_arg(argc, argv, dwim_ok,
> -					     &new_branch_info, &opts, &rev,
> +					     &new_branch_info, opts, &rev,
>  					     &dwim_remotes_matched);
>  		argv += n;
>  		argc -= n;
>  	}
>  
>  	if (argc) {
> -		parse_pathspec(&opts.pathspec, 0,
> -			       opts.patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
> +		parse_pathspec(&opts->pathspec, 0,
> +			       opts->patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
>  			       prefix, argv);
>  
> -		if (!opts.pathspec.nr)
> +		if (!opts->pathspec.nr)
>  			die(_("invalid path specification"));
>  
>  		/*
>  		 * Try to give more helpful suggestion.
>  		 * new_branch && argc > 1 will be caught later.
>  		 */
> -		if (opts.new_branch && argc == 1)
> +		if (opts->new_branch && argc == 1)
>  			die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
> -				argv[0], opts.new_branch);
> +				argv[0], opts->new_branch);
>  
> -		if (opts.force_detach)
> +		if (opts->force_detach)
>  			die(_("git checkout: --detach does not take a path argument '%s'"),
>  			    argv[0]);
>  
> -		if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
> +		if (1 < !!opts->writeout_stage + !!opts->force + !!opts->merge)
>  			die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
>  			      "checking out of the index."));
>  	}
>  
> -	if (opts.new_branch) {
> +	if (opts->new_branch) {
>  		struct strbuf buf = STRBUF_INIT;
>  
> -		if (opts.new_branch_force)
> -			opts.branch_exists = validate_branchname(opts.new_branch, &buf);
> +		if (opts->new_branch_force)
> +			opts->branch_exists = validate_branchname(opts->new_branch, &buf);
>  		else
> -			opts.branch_exists =
> -				validate_new_branchname(opts.new_branch, &buf, 0);
> +			opts->branch_exists =
> +				validate_new_branchname(opts->new_branch, &buf, 0);
>  		strbuf_release(&buf);
>  	}
>  
>  	UNLEAK(opts);
> -	if (opts.patch_mode || opts.pathspec.nr) {
> -		int ret = checkout_paths(&opts, new_branch_info.name);
> +	if (opts->patch_mode || opts->pathspec.nr) {
> +		int ret = checkout_paths(opts, new_branch_info.name);
>  		if (ret && dwim_remotes_matched > 1 &&
>  		    advice_checkout_ambiguous_remote_branch_name)
>  			advise(_("'%s' matched more than one remote tracking branch.\n"
> @@ -1405,6 +1444,49 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
>  			       dwim_remotes_matched);
>  		return ret;
>  	} else {
> -		return checkout_branch(&opts, &new_branch_info);
> +		return checkout_branch(opts, &new_branch_info);
>  	}
>  }
> +
> +int cmd_checkout(int argc, const char **argv, const char *prefix)
> +{
> +	struct checkout_opts opts;
> +	struct option *options = NULL;
> +	int ret;
> +
> +	options = add_common_options(&opts, options);
> +	options = add_switch_branch_options(&opts, options);
> +	options = add_checkout_path_options(&opts, options);
> +	ret = checkout_main(argc, argv, prefix, &opts,
> +			    options, checkout_usage);
> +	FREE_AND_NULL(options);
> +	return ret;
> +}
> +
> +int cmd_switch_branch(int argc, const char **argv, const char *prefix)
> +{
> +	struct checkout_opts opts;
> +	struct option *options = NULL;
> +	int ret;
> +
> +	options = add_common_options(&opts, options);
> +	options = add_switch_branch_options(&opts, options);
> +	ret = checkout_main(argc, argv, prefix, &opts,
> +			    options, switch_branch_usage);
> +	FREE_AND_NULL(options);
> +	return ret;
> +}
> +
> +int cmd_restore_paths(int argc, const char **argv, const char *prefix)
> +{
> +	struct checkout_opts opts;
> +	struct option *options = NULL;
> +	int ret;
> +
> +	options = add_common_options(&opts, options);
> +	options = add_checkout_path_options(&opts, options);
> +	ret = checkout_main(argc, argv, prefix, &opts,
> +			    options, restore_paths_usage);
> +	FREE_AND_NULL(options);
> +	return ret;
> +}
> diff --git a/git.c b/git.c
> index 2f604a41ea..e8a76a99da 100644
> --- a/git.c
> +++ b/git.c
> @@ -542,6 +542,7 @@ static struct cmd_struct commands[] = {
>  	{ "replace", cmd_replace, RUN_SETUP },
>  	{ "rerere", cmd_rerere, RUN_SETUP },
>  	{ "reset", cmd_reset, RUN_SETUP },
> +	{ "restore-paths", cmd_restore_paths, RUN_SETUP | NEED_WORK_TREE },
>  	{ "rev-list", cmd_rev_list, RUN_SETUP | NO_PARSEOPT },
>  	{ "rev-parse", cmd_rev_parse, NO_PARSEOPT },
>  	{ "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
> @@ -557,6 +558,7 @@ static struct cmd_struct commands[] = {
>  	{ "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
>  	{ "stripspace", cmd_stripspace },
>  	{ "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT },
> +	{ "switch-branch", cmd_switch_branch, RUN_SETUP | NEED_WORK_TREE },
>  	{ "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
>  	{ "tag", cmd_tag, RUN_SETUP | DELAY_PAGER_CONFIG },
>  	{ "unpack-file", cmd_unpack_file, RUN_SETUP | NO_PARSEOPT },
> diff --git a/parse-options-cb.c b/parse-options-cb.c
> index 8c9edce52f..c609d52926 100644
> --- a/parse-options-cb.c
> +++ b/parse-options-cb.c
> @@ -126,7 +126,7 @@ struct option *parse_options_concat(struct option *a, struct option *b)
>  	struct option *ret;
>  	size_t i, a_len = 0, b_len = 0;
>  
> -	for (i = 0; a[i].type != OPTION_END; i++)
> +	for (i = 0; a && a[i].type != OPTION_END; i++)
>  		a_len++;
>  	for (i = 0; b[i].type != OPTION_END; i++)
>  		b_len++;
> -- 8< --

> I like the idea of splitting those commands up, in fact it is
> something I've been considering working on myself.  I do think we
> should consider if we want to change the behaviour of those new
> commands in any way compared to 'git checkout', since we're starting
> with a clean slate.
>
> One thing in particular that I have in mind is something I'm currently
> working on, namely adding a --index flag to 'git checkout', which
> would make 'git checkout' work in non-overlay mode (for more
> discussion on that see also [*1*].

>
> Thomas Gummerer <t.gummerer@gmail.com> writes:
>
> > I like the idea of splitting those commands up, in fact it is
> > something I've been considering working on myself.  I do think we
> > should consider if we want to change the behaviour of those new
> > commands in any way compared to 'git checkout', since we're starting
> > with a clean slate.

> > One thing in particular that I have in mind is something I'm currently
> > working on, namely adding a --index flag to 'git checkout', which
> > would make 'git checkout' work in non-overlay mode (for more
> > discussion on that see also [*1*].
>
> Ah, thanks for reminding me of that.  That explains why I felt
> uneasy to see "restore" in the proposed command name.

> On Mon, Nov 19, 2018 at 04:19:53PM +0100, Duy Nguyen wrote:
>> I promise to come back with something better (at least it still
>> sounds better in my mind). If that idea does not work out, we can
>> come back and see if we can improve this.
>
> So this is it. The patch isn't pretty, mostly as a proof of
> concept. Just look at the three functions at the bottom of checkout.c,
> which is the main thing.
>
> This patch tries to split "git checkout" command in two new ones:
>
> - git switch-branch is all about switching branches

> The main idea is these two commands will co-exist with the good old
> 'git checkout', which will NOT be deprecated. Old timers will still
> use "git checkout". But new people should be introduced to the new two
> instead. And the new ones are just as capable as "git checkout".
>
> Since the three commands will co-exist (with duplicate functionality),
> maintenance cost must be kept to minimum. The way I did this is simply
> split the command line options into three pieces: common,
> switch-branch and checkout-paths. "git checkout" has all three, the
> other two have common and another piece.
>
> With this, a new option added to git checkout will be automatically
> available in either switch-branch or checkout-paths. Bug fixes apply
> to all relevant commands.
>
> Later on, we could start to add a bit more stuff in, e.g. some form of
> disambiguation is no longer needed when running as switch-branch, or
> restore-paths.
>
> So, what do you think?

> > So, what do you think?
>
> That "git checkout" does too many things is something that keeps coming
> up in online discussions about Git's UI. Two things:
>
> a) It would really help to have some comparison of cases where these
>    split commands are much clearer or less ambiguous than
>    git-checkout. I can think of some (e.g. branch with the same name as
>    a file) but having some overall picture of what the new UI looks like
>    with solved / not solved cases would be nice. Also a comparison with
>    other SCMs people find less confusing (svn, hg, bzr, ...)

> b) I think we really need to have some end-game where we'd actually
>    switch away from "checkout" (which we could still auto-route to new
>    commands in perpetuity, but print a warning or error). Otherwise
>    we'll just end up with https://xkcd.com/927/ and more UI confusion
>    for all.

>
>
> On Tue, Nov 20 2018, Duy Nguyen wrote:
>
> > On Mon, Nov 19, 2018 at 04:19:53PM +0100, Duy Nguyen wrote:
> >> I promise to come back with something better (at least it still
> >> sounds better in my mind). If that idea does not work out, we can
> >> come back and see if we can improve this.
> >
> > So this is it. The patch isn't pretty, mostly as a proof of
> > concept. Just look at the three functions at the bottom of checkout.c,
> > which is the main thing.
> >
> > This patch tries to split "git checkout" command in two new ones:
> >
> > - git switch-branch is all about switching branches
>
> Isn't this going to also take the other ref arguments 'git checkout'
> takes now? I.e. tags, detached HEADs etc? I'm reminded of the discussion
> about what "range-diff" should be called :)

> > Later on, we could start to add a bit more stuff in, e.g. some form of
> > disambiguation is no longer needed when running as switch-branch, or
> > restore-paths.
> >
> > So, what do you think?

> That "git checkout" does too many things is something that keeps coming
> up in online discussions about Git's UI. Two things:
>
> a) It would really help to have some comparison of cases where these
>    split commands are much clearer or less ambiguous than
>    git-checkout. I can think of some (e.g. branch with the same name as
>    a file) but having some overall picture of what the new UI looks like
>    with solved / not solved cases would be nice. Also a comparison with
>    other SCMs people find less confusing (svn, hg, bzr, ...)

> b) I think we really need to have some end-game where we'd actually
>    switch away from "checkout" (which we could still auto-route to new
>    commands in perpetuity, but print a warning or error). Otherwise
>    we'll just end up with https://xkcd.com/927/ and more UI confusion
>    for all.

> Maybe we need to step back and consider what the command does.
> And from that I would name it "rewire-HEAD-and-update-index&worktree"
> and then simplify from there. For the beginner user, the concept of
> HEAD might be overwhelming, such that we don't want to have that
> in there.

>
> There is currently no caller that calls this function with "a" being
> NULL. But it will be introduced shortly. It is used to construct the
> option array from scratch, e.g.
>
>    struct parse_options opts = NULL;
>    opts = parse_options_concat(opts, opts_1);
>    opts = parse_options_concat(opts, opts_2);

>
> On Tue, Nov 27, 2018 at 8:53 AM Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> >
> > There is currently no caller that calls this function with "a" being
> > NULL. But it will be introduced shortly. It is used to construct the
> > option array from scratch, e.g.
> >
> >    struct parse_options opts = NULL;
> >    opts = parse_options_concat(opts, opts_1);
> >    opts = parse_options_concat(opts, opts_2);
>
> While this addresses the immediate needs, I'd prefer to think
> about the API exposure of parse_options_concat,
> (related: do we want to have docs in its header file?)
> and I'd recommend to make it symmetrical, i.e.
> allow the second argument to also be NULL?

> There is currently no caller that calls this function with "a" being
> NULL. But it will be introduced shortly. It is used to construct the
> option array from scratch, e.g.
>
>    struct parse_options opts = NULL;

>    opts = parse_options_concat(opts, opts_1);
>    opts = parse_options_concat(opts, opts_2);
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  parse-options-cb.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/parse-options-cb.c b/parse-options-cb.c
> index 8c9edce52f..c609d52926 100644
> --- a/parse-options-cb.c
> +++ b/parse-options-cb.c
> @@ -126,7 +126,7 @@ struct option *parse_options_concat(struct option *a, struct option *b)
>  	struct option *ret;
>  	size_t i, a_len = 0, b_len = 0;
>  
> -	for (i = 0; a[i].type != OPTION_END; i++)
> +	for (i = 0; a && a[i].type != OPTION_END; i++)
>  		a_len++;
>  	for (i = 0; b[i].type != OPTION_END; i++)
>  		b_len++;

> +static struct option *add_switch_branch_options(struct checkout_opts *opts,
> +						struct option *prevopts)
> +{
> +	struct option options[] = {
>  		OPT_STRING('b', NULL, &opts->new_branch, N_("branch"),
>  			   N_("create and checkout a new branch")),

>  	/*
>  	 * If new checkout options are added, skip_merge_working_tree
> @@ -1056,7 +1068,7 @@ static int parse_branchname_arg(int argc, const char **argv,
>  	arg = argv[0];
>  	dash_dash_pos = -1;
>  	for (i = 0; i < argc; i++) {
> -		if (!strcmp(argv[i], "--")) {
> +		if (opts->accept_pathspec && !strcmp(argv[i], "--")) {
>  			dash_dash_pos = i;
>  			break;
>  		}
> @@ -1067,6 +1079,8 @@ static int parse_branchname_arg(int argc, const char **argv,
>  		has_dash_dash = 1; /* case (3) or (1) */
>  	else if (dash_dash_pos >= 2)
>  		die(_("only one reference expected, %d given."), dash_dash_pos);
> +	else if (!opts->accept_pathspec)
> +		has_dash_dash = 1;
>  
>  	if (!strcmp(arg, "-"))
>  		arg = "@{-1}";
> @@ -1291,30 +1305,23 @@ static struct option *add_checkout_path_options(struct checkout_opts *opts,
>  	return newopts;
>  }
>  
> -int cmd_checkout(int argc, const char **argv, const char *prefix)
> +static int checkout_main(int argc, const char **argv, const char *prefix,
> +			 struct checkout_opts *opts, struct option *options,
> +			 const char * const usagestr[])
>  {
> -	struct checkout_opts real_opts;
> -	struct checkout_opts *opts = &real_opts;
>  	struct branch_info new_branch_info;
>  	int dwim_remotes_matched = 0;
> -	struct option *options = NULL;
>  
> -	memset(opts, 0, sizeof(*opts));
>  	memset(&new_branch_info, 0, sizeof(new_branch_info));
>  	opts->overwrite_ignore = 1;
>  	opts->prefix = prefix;
>  	opts->show_progress = -1;
> -	opts->dwim_new_local_branch = 1;
>  
>  	git_config(git_checkout_config, opts);
>  
>  	opts->track = BRANCH_TRACK_UNSPECIFIED;
>  
> -	options = add_common_options(opts, options);
> -	options = add_switch_branch_options(opts, options);
> -	options = add_checkout_path_options(opts, options);
> -
> -	argc = parse_options(argc, argv, prefix, options, checkout_usage,
> +	argc = parse_options(argc, argv, prefix, options, usagestr,
>  			     PARSE_OPT_KEEP_DASHDASH);
>  
>  	if (opts->show_progress < 0) {
> @@ -1381,7 +1388,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
>  					     &dwim_remotes_matched);
>  		argv += n;
>  		argc -= n;
> -	}
> +	} else if (!opts->empty_arg_ok)
> +		usage_with_options(usagestr, options);
>  
>  	if (argc) {
>  		parse_pathspec(&opts->pathspec, 0,
> @@ -1443,3 +1451,60 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
>  		return checkout_branch(opts, &new_branch_info);
>  	}
>  }
> +
> +int cmd_checkout(int argc, const char **argv, const char *prefix)
> +{
> +	struct checkout_opts opts;
> +	struct option *options = NULL;
> +	int ret;
> +
> +	memset(&opts, 0, sizeof(opts));
> +	opts.dwim_new_local_branch = 1;
> +	opts.accept_pathspec = 1;
> +	opts.empty_arg_ok = 1;
> +
> +	options = add_common_options(&opts, options);
> +	options = add_switch_branch_options(&opts, options);
> +	options = add_checkout_path_options(&opts, options);
> +
> +	ret = checkout_main(argc, argv, prefix, &opts,
> +			    options, checkout_usage);
> +	FREE_AND_NULL(options);
> +	return ret;
> +}
> +
> +int cmd_switch_branch(int argc, const char **argv, const char *prefix)
> +{
> +	struct checkout_opts opts;
> +	struct option *options = NULL;
> +	int ret;
> +
> +	memset(&opts, 0, sizeof(opts));
> +	opts.dwim_new_local_branch = 1;
> +
> +	options = add_common_options(&opts, options);
> +	options = add_switch_branch_options(&opts, options);
> +
> +	ret = checkout_main(argc, argv, prefix, &opts,
> +			    options, switch_branch_usage);
> +	FREE_AND_NULL(options);
> +	return ret;
> +}
> +
> +int cmd_checkout_files(int argc, const char **argv, const char *prefix)
> +{
> +	struct checkout_opts opts;
> +	struct option *options = NULL;
> +	int ret;
> +
> +	memset(&opts, 0, sizeof(opts));
> +	opts.accept_pathspec = 1;
> +
> +	options = add_common_options(&opts, options);
> +	options = add_checkout_path_options(&opts, options);
> +
> +	ret = checkout_main(argc, argv, prefix, &opts,
> +			    options, checkout_files_usage);
> +	FREE_AND_NULL(options);
> +	return ret;
> +}
> diff --git a/git.c b/git.c
> index 2f604a41ea..3b86ba765c 100644
> --- a/git.c
> +++ b/git.c
> @@ -457,6 +457,7 @@ static struct cmd_struct commands[] = {
>  	{ "check-mailmap", cmd_check_mailmap, RUN_SETUP },
>  	{ "check-ref-format", cmd_check_ref_format, NO_PARSEOPT  },
>  	{ "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
> +	{ "checkout-files", cmd_checkout_files, RUN_SETUP | NEED_WORK_TREE },
>  	{ "checkout-index", cmd_checkout_index,
>  		RUN_SETUP | NEED_WORK_TREE},
>  	{ "cherry", cmd_cherry, RUN_SETUP },
> @@ -557,6 +558,7 @@ static struct cmd_struct commands[] = {
>  	{ "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
>  	{ "stripspace", cmd_stripspace },
>  	{ "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT },
> +	{ "switch-branch", cmd_switch_branch, RUN_SETUP | NEED_WORK_TREE },
>  	{ "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
>  	{ "tag", cmd_tag, RUN_SETUP | DELAY_PAGER_CONFIG },
>  	{ "unpack-file", cmd_unpack_file, RUN_SETUP | NO_PARSEOPT },

>
> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
>
> > The good old "git checkout" command is still here and will be until
> > all (or most of users) are sick of it.
>
> Two comments on the goal (the implementation looked reasonable
> assuming the reader agrees with the gaol).
>
> At least to me, the verb "switch" needs two things to switch
> between, i.e. "switch A and B", unless it is "switch to X".
> Either "switch-to-branch" or simply "switch-to", perhaps?
>
> As I already hinted in my response to Stefan (?) about
> checkout-from-tree vs checkout-from-index, a command with multiple
> modes of operation is not confusing to people with the right mental
> model, and I suspect that having two separate commands for "checking
> out a branch" and "checking out paths" that is done by this step
> would help users to form the right mental model.

> So I tend to think
> these two are "training wheels", and suspect that once they got it,
> nobody will become "sick of" the single "checkout" command that can
> be used to do either.  It's just the matter of being aware what can
> be done (which requires the right mental model) and how to tell Git
> what the user wants it do (two separate commands, operating mode
> option, or just the implied command line syntax---once the user
> knows what s/he is doing, these do not make that much a difference).

>
> On Wed, Nov 28, 2018 at 7:03 AM Junio C Hamano <gitster@pobox.com> wrote:
> >
> > Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
> >
> > > The good old "git checkout" command is still here and will be until
> > > all (or most of users) are sick of it.
> >
> > Two comments on the goal (the implementation looked reasonable
> > assuming the reader agrees with the gaol).
> >
> > At least to me, the verb "switch" needs two things to switch
> > between, i.e. "switch A and B", unless it is "switch to X".
> > Either "switch-to-branch" or simply "switch-to", perhaps?
> >
> > As I already hinted in my response to Stefan (?) about
> > checkout-from-tree vs checkout-from-index, a command with multiple
> > modes of operation is not confusing to people with the right mental
> > model, and I suspect that having two separate commands for "checking
> > out a branch" and "checking out paths" that is done by this step
> > would help users to form the right mental model.
>
> Since the other one is already "checkout-files", maybe this one could
> just be "checkout-branch".

>
> On Wed, Nov 28, 2018 at 7:31 AM Duy Nguyen <pclouds@gmail.com> wrote:
> >
> > On Wed, Nov 28, 2018 at 7:03 AM Junio C Hamano <gitster@pobox.com> wrote:
> > >
> > > Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
> > >
> > > > The good old "git checkout" command is still here and will be until
> > > > all (or most of users) are sick of it.
> > >
> > > Two comments on the goal (the implementation looked reasonable
> > > assuming the reader agrees with the gaol).
> > >
> > > At least to me, the verb "switch" needs two things to switch
> > > between, i.e. "switch A and B", unless it is "switch to X".
> > > Either "switch-to-branch" or simply "switch-to", perhaps?
> > >
> > > As I already hinted in my response to Stefan (?) about
> > > checkout-from-tree vs checkout-from-index, a command with multiple
> > > modes of operation is not confusing to people with the right mental
> > > model, and I suspect that having two separate commands for "checking
> > > out a branch" and "checking out paths" that is done by this step
> > > would help users to form the right mental model.
> >
> > Since the other one is already "checkout-files", maybe this one could
> > just be "checkout-branch".
>
> I dislike the checkout-* names, as we already have checkout-index
> as plumbing, so it would be confusing as to which checkout-* command
> should be used when and why as it seems the co-index moves
> content *from index* to the working tree, but the co-files moves content
> *to files*, whereas checkout-branch is neither 'moving' to or from a branch
> but rather 'switching' to that branch.

> I dislike the checkout-* names, as we already have checkout-index
> as plumbing, so it would be confusing as to which checkout-* command
> should be used when and why as it seems the co-index moves
> content *from index* to the working tree, but the co-files moves content
> *to files*, whereas checkout-branch is neither 'moving' to or from a branch
> but rather 'switching' to that branch.

>
> On Wed, Nov 28, 2018 at 7:03 AM Junio C Hamano <gitster@pobox.com> wrote:
> >
> > Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
> >
> > > The good old "git checkout" command is still here and will be until
> > > all (or most of users) are sick of it.
> >
> > Two comments on the goal (the implementation looked reasonable
> > assuming the reader agrees with the gaol).
> >
> > At least to me, the verb "switch" needs two things to switch
> > between, i.e. "switch A and B", unless it is "switch to X".
> > Either "switch-to-branch" or simply "switch-to", perhaps?
> >
> > As I already hinted in my response to Stefan (?) about
> > checkout-from-tree vs checkout-from-index, a command with multiple
> > modes of operation is not confusing to people with the right mental
> > model, and I suspect that having two separate commands for "checking
> > out a branch" and "checking out paths" that is done by this step
> > would help users to form the right mental model.
>
> Since the other one is already "checkout-files", maybe this one could
> just be "checkout-branch".
>
> > So I tend to think
> > these two are "training wheels", and suspect that once they got it,
> > nobody will become "sick of" the single "checkout" command that can
> > be used to do either.  It's just the matter of being aware what can
> > be done (which requires the right mental model) and how to tell Git
> > what the user wants it do (two separate commands, operating mode
> > option, or just the implied command line syntax---once the user
> > knows what s/he is doing, these do not make that much a difference).
>
> I would hope this becomes better defaults and being used 90% of time.
> Even though I know "git checkout" quite well, it still bites me from
> time to time. Having the right mental model is one thing. Having to
> think a bit every time to write "git checkout" with the right syntax,
> and whether you need "--" (that ambiguation problem can still bite you
> from time to time), is frankly something I'd rather avoid.
> --
> Duy

>
> > Since the other one is already "checkout-files", maybe this one could just be "checkout-branch".
>
> I rather like switch-branch and dislike the word "checkout" since it
> has been overloaded in git for so long (does it mean moving HEAD or
> copying files to my working tree?)
>
> > nobody will become "sick of" the single "checkout" command that can
>
> I have to admit I'm already sick of the checkout command. :-p I can
> see myself using these two new commands 100% of the time and never
> missing the old one.
>
> Some behaviors I'd expect to see from these commands (I haven't yet
> checked to see if you've already done this):
>
> git checkout-files <tree-ish>
> should reset all the files in the repository regardless of the current
> directory - it should produce the same effect as "git reset --hard
> <tree-ish> && git reset HEAD@{1}". It should also delete
> locally-created files that aren't present in <tree-ish>, such that the
> final working tree is exactly identical to what was committed in that
> tree-ish.
>
> git checkout-files foo -- myfile.txt
> should delete myfile.txt if it is present locally but not present in foo.
>
> git checkout-files foo -- .
> should recursively checkout all files in the current folder and all
> subfolders, and delete any locally-created files if they're not
> present in foo.
>
> git checkout-files should never move HEAD in any circumstance.
>
> Suggestion:
> If git checkout-files overwrites or deletes any locally-modified files
> from the workspace or index, those files could be auto-stashed. That
> would make it easy to restore them in the event of a mistyped command.
> Auto-stashing could be suppressed with a command-line argument (with
> alternate behaviors being fail-if-modified or always-overwrite).
>
> Idea:
> If git checkout-files modifies the submodules file, it could also
> auto-update the submodules. (For example, with something like "git
> submodule update --init --recursive --progress").
>
>   - Stefan
> On Wed, Nov 28, 2018 at 7:31 AM Duy Nguyen <pclouds@gmail.com> wrote:
> >
> > On Wed, Nov 28, 2018 at 7:03 AM Junio C Hamano <gitster@pobox.com> wrote:
> > >
> > > Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
> > >
> > > > The good old "git checkout" command is still here and will be until
> > > > all (or most of users) are sick of it.
> > >
> > > Two comments on the goal (the implementation looked reasonable
> > > assuming the reader agrees with the gaol).
> > >
> > > At least to me, the verb "switch" needs two things to switch
> > > between, i.e. "switch A and B", unless it is "switch to X".
> > > Either "switch-to-branch" or simply "switch-to", perhaps?
> > >
> > > As I already hinted in my response to Stefan (?) about
> > > checkout-from-tree vs checkout-from-index, a command with multiple
> > > modes of operation is not confusing to people with the right mental
> > > model, and I suspect that having two separate commands for "checking
> > > out a branch" and "checking out paths" that is done by this step
> > > would help users to form the right mental model.
> >
> > Since the other one is already "checkout-files", maybe this one could
> > just be "checkout-branch".
> >
> > > So I tend to think
> > > these two are "training wheels", and suspect that once they got it,
> > > nobody will become "sick of" the single "checkout" command that can
> > > be used to do either.  It's just the matter of being aware what can
> > > be done (which requires the right mental model) and how to tell Git
> > > what the user wants it do (two separate commands, operating mode
> > > option, or just the implied command line syntax---once the user
> > > knows what s/he is doing, these do not make that much a difference).
> >
> > I would hope this becomes better defaults and being used 90% of time.
> > Even though I know "git checkout" quite well, it still bites me from
> > time to time. Having the right mental model is one thing. Having to
> > think a bit every time to write "git checkout" with the right syntax,
> > and whether you need "--" (that ambiguation problem can still bite you
> > from time to time), is frankly something I'd rather avoid.
> > --
> > Duy

>
> Although I have no problem with "switch-branch" as a command name,
> some alternative names we might consider for switch-branch might be:
>
> chbranch
> swbranch
> switch
> branch change (as a subcommand for the "branch" command)
>
> I've personally been using "chbranch" as an alias for this
> functionality for some time.
>
>   - Stefan
> On Wed, Nov 28, 2018 at 3:22 PM Stefan Xenos <sxenos@google.com> wrote:
> >
> > > Since the other one is already "checkout-files", maybe this one could just be "checkout-branch".
> >
> > I rather like switch-branch and dislike the word "checkout" since it
> > has been overloaded in git for so long (does it mean moving HEAD or
> > copying files to my working tree?)
> >
> > > nobody will become "sick of" the single "checkout" command that can
> >
> > I have to admit I'm already sick of the checkout command. :-p I can
> > see myself using these two new commands 100% of the time and never
> > missing the old one.
> >
> > Some behaviors I'd expect to see from these commands (I haven't yet
> > checked to see if you've already done this):
> >
> > git checkout-files <tree-ish>
> > should reset all the files in the repository regardless of the current
> > directory - it should produce the same effect as "git reset --hard
> > <tree-ish> && git reset HEAD@{1}". It should also delete
> > locally-created files that aren't present in <tree-ish>, such that the
> > final working tree is exactly identical to what was committed in that
> > tree-ish.
> >
> > git checkout-files foo -- myfile.txt
> > should delete myfile.txt if it is present locally but not present in foo.
> >
> > git checkout-files foo -- .
> > should recursively checkout all files in the current folder and all
> > subfolders, and delete any locally-created files if they're not
> > present in foo.
> >
> > git checkout-files should never move HEAD in any circumstance.
> >
> > Suggestion:
> > If git checkout-files overwrites or deletes any locally-modified files
> > from the workspace or index, those files could be auto-stashed. That
> > would make it easy to restore them in the event of a mistyped command.
> > Auto-stashing could be suppressed with a command-line argument (with
> > alternate behaviors being fail-if-modified or always-overwrite).
> >
> > Idea:
> > If git checkout-files modifies the submodules file, it could also
> > auto-update the submodules. (For example, with something like "git
> > submodule update --init --recursive --progress").
> >
> >   - Stefan
> > On Wed, Nov 28, 2018 at 7:31 AM Duy Nguyen <pclouds@gmail.com> wrote:
> > >
> > > On Wed, Nov 28, 2018 at 7:03 AM Junio C Hamano <gitster@pobox.com> wrote:
> > > >
> > > > Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
> > > >
> > > > > The good old "git checkout" command is still here and will be until
> > > > > all (or most of users) are sick of it.
> > > >
> > > > Two comments on the goal (the implementation looked reasonable
> > > > assuming the reader agrees with the gaol).
> > > >
> > > > At least to me, the verb "switch" needs two things to switch
> > > > between, i.e. "switch A and B", unless it is "switch to X".
> > > > Either "switch-to-branch" or simply "switch-to", perhaps?
> > > >
> > > > As I already hinted in my response to Stefan (?) about
> > > > checkout-from-tree vs checkout-from-index, a command with multiple
> > > > modes of operation is not confusing to people with the right mental
> > > > model, and I suspect that having two separate commands for "checking
> > > > out a branch" and "checking out paths" that is done by this step
> > > > would help users to form the right mental model.
> > >
> > > Since the other one is already "checkout-files", maybe this one could
> > > just be "checkout-branch".
> > >
> > > > So I tend to think
> > > > these two are "training wheels", and suspect that once they got it,
> > > > nobody will become "sick of" the single "checkout" command that can
> > > > be used to do either.  It's just the matter of being aware what can
> > > > be done (which requires the right mental model) and how to tell Git
> > > > what the user wants it do (two separate commands, operating mode
> > > > option, or just the implied command line syntax---once the user
> > > > knows what s/he is doing, these do not make that much a difference).
> > >
> > > I would hope this becomes better defaults and being used 90% of time.
> > > Even though I know "git checkout" quite well, it still bites me from
> > > time to time. Having the right mental model is one thing. Having to
> > > think a bit every time to write "git checkout" with the right syntax,
> > > and whether you need "--" (that ambiguation problem can still bite you
> > > from time to time), is frankly something I'd rather avoid.
> > > --
> > > Duy

> Although I have no problem with "switch-branch" as a command name,
> some alternative names we might consider for switch-branch might be:
>
> chbranch
> swbranch

>
> Stefan Xenos <sxenos@google.com> writes:
>
> > Although I have no problem with "switch-branch" as a command name,
> > some alternative names we might consider for switch-branch might be:
> >
> > chbranch
> > swbranch
>
> Please never go in that direction.  So far, we made a conscious
> effort to keep the names of most frequently used subcommand to
> proper words that can be understood by coders (IOW, I expect they
> know what 'grep' is, even though that may not be a 'proper word').
>
> > switch
> > branch change (as a subcommand for the "branch" command)
>
> It is more like moving to the branch to work on.  I think 'switch'
> is something SVN veterans may find familiar.  Both are much better
> than ch/swbranch that are overly cryptic.

> Some behaviors I'd expect to see from these commands (I haven't yet
> checked to see if you've already done this):
>
> git checkout-files <tree-ish>
> should reset all the files in the repository regardless of the current
> directory - it should produce the same effect as "git reset --hard
> <tree-ish> && git reset HEAD@{1}". It should also delete
> locally-created files that aren't present in <tree-ish>, such that the
> final working tree is exactly identical to what was committed in that
> tree-ish.
>
> git checkout-files foo -- myfile.txt
> should delete myfile.txt if it is present locally but not present in foo.
>
> git checkout-files foo -- .
> should recursively checkout all files in the current folder and all
> subfolders, and delete any locally-created files if they're not
> present in foo.

> Suggestion:
> If git checkout-files overwrites or deletes any locally-modified files
> from the workspace or index, those files could be auto-stashed. That
> would make it easy to restore them in the event of a mistyped command.
> Auto-stashing could be suppressed with a command-line argument (with
> alternate behaviors being fail-if-modified or always-overwrite).

> > Idea:
> > If git checkout-files modifies the submodules file, it could also
> > auto-update the submodules. (For example, with something like "git
> > submodule update --init --recursive --progress").
>
> This one is tricky because we should deal with submodule autoupdate
> consistently across all porcelain commands (or at least common ones),
> not just checkout-files. I'd prefer to delay this until later. Once we
> figure out what to do with other commands, then we can still change
> defaults for checkout-files.

>
> > > Idea:
> > > If git checkout-files modifies the submodules file, it could also
> > > auto-update the submodules. (For example, with something like "git
> > > submodule update --init --recursive --progress").
> >
> > This one is tricky because we should deal with submodule autoupdate
> > consistently across all porcelain commands (or at least common ones),
> > not just checkout-files. I'd prefer to delay this until later. Once we
> > figure out what to do with other commands, then we can still change
> > defaults for checkout-files.
>
> checkout/reset are respecting the submodule.recurse setting for this
> already, and as your patches only change the UX frontend
>
>     git -c submodule.recurse checkout-files <pathsspec>
>
> would also touch submodules. Given that deep down in
> the submodules it's all about files again, we could think
> checkout-files is still a good name.
>
> I think Stefan X. is asking for making submodule.recurse
> to default to true, which is indeed unrelated to this.

>
> Which brings us back to your "git checkout-files <tree-ish>" use case
> above. It should be treat the same way in my opinion, so we either do
>
>  git checkout-files --from=tree-ish :/
>
> or
>
>  git checkout-files --from=tree-ish .
>
> But "git checkout-files --from=tree-ish" alone is rejected.

> > Suggestion:
> > If git checkout-files overwrites or deletes any locally-modified files
> > from the workspace or index, those files could be auto-stashed. That
> > would make it easy to restore them in the event of a mistyped command.
> > Auto-stashing could be suppressed with a command-line argument (with
> > alternate behaviors being fail-if-modified or always-overwrite).
>
> Stashing I think is not the right tool for this. When you stash, you
> plan to retrieve it back later but here you should rarely ever need to
> unstash until the accident. For recovery from accidents like this, I
> have another thing in queue to achieve the same (I'm calling it
> "backup log" now). So we will have the same functionality, just with
> different means.

> The assumption made is here
>
> - "git checkout" is a horrible monster that should only be touched
>   with a two-meter pole
>
> - there are other commands that can achieve the same thing

>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  Documentation/git-branch.txt           |  8 ++--
>  Documentation/git-check-ref-format.txt |  2 +-
>  Documentation/git-format-patch.txt     |  2 +-
>  Documentation/git-merge-base.txt       |  2 +-
>  Documentation/git-rebase.txt           |  2 +-
>  Documentation/git-remote.txt           |  2 +-
>  Documentation/git-rerere.txt           | 10 ++---
>  Documentation/git-reset.txt            | 18 ++++-----
>  Documentation/git-revert.txt           |  2 +-
>  Documentation/git-stash.txt            |  6 +--
>  Documentation/gitattributes.txt        |  2 +-
>  Documentation/gitcli.txt               |  4 +-
>  Documentation/gitcore-tutorial.txt     | 18 ++++-----
>  Documentation/giteveryday.txt          | 24 ++++++------
>  Documentation/githooks.txt             |  5 ++-
>  Documentation/gittutorial-2.txt        |  2 +-
>  Documentation/gittutorial.txt          |  4 +-
>  Documentation/revisions.txt            |  2 +-
>  Documentation/user-manual.txt          | 54 +++++++++++++-------------
>  advice.c                               |  2 +-
>  sha1-name.c                            |  2 +-
>  wt-status.c                            |  2 +-
>  22 files changed, 88 insertions(+), 87 deletions(-)
>
> diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
> index bf5316ffa9..1564df47d2 100644
> --- a/Documentation/git-branch.txt
> +++ b/Documentation/git-branch.txt
> @@ -48,7 +48,7 @@ The command's second form creates a new branch head named <branchname>
>  which points to the current `HEAD`, or <start-point> if given.
>  
>  Note that this will create the new branch, but it will not switch the
> -working tree to it; use "git checkout <newbranch>" to switch to the
> +working tree to it; use "git switch-branch <newbranch>" to switch to the
>  new branch.
>  
>  When a local branch is started off a remote-tracking branch, Git sets up the
> @@ -194,7 +194,7 @@ This option is only applicable in non-verbose mode.
>  +
>  This behavior is the default when the start point is a remote-tracking branch.
>  Set the branch.autoSetupMerge configuration variable to `false` if you
> -want `git checkout` and `git branch` to always behave as if `--no-track`
> +want `git switch-branch` and `git branch` to always behave as if `--no-track`
>  were given. Set it to `always` if you want this behavior when the
>  start-point is either a local or remote-tracking branch.
>  
> @@ -293,7 +293,7 @@ Start development from a known tag::
>  $ git clone git://git.kernel.org/pub/scm/.../linux-2.6 my2.6
>  $ cd my2.6
>  $ git branch my2.6.14 v2.6.14   <1>
> -$ git checkout my2.6.14
> +$ git switch-branch my2.6.14
>  ------------
>  +
>  <1> This step and the next one could be combined into a single step with
> @@ -319,7 +319,7 @@ NOTES
>  -----
>  
>  If you are creating a branch that you want to checkout immediately, it is
> -easier to use the git checkout command with its `-b` option to create
> +easier to use the "git switch-branch" command with its `-b` option to create
>  a branch and check it out with a single command.
>  
>  The options `--contains`, `--no-contains`, `--merged` and `--no-merged`
> diff --git a/Documentation/git-check-ref-format.txt b/Documentation/git-check-ref-format.txt
> index d9de992585..38c2169d7a 100644
> --- a/Documentation/git-check-ref-format.txt
> +++ b/Documentation/git-check-ref-format.txt
> @@ -88,7 +88,7 @@ but it is explicitly forbidden at the beginning of a branch name).
>  When run with `--branch` option in a repository, the input is first
>  expanded for the ``previous checkout syntax''
>  `@{-n}`.  For example, `@{-1}` is a way to refer the last thing that
> -was checked out using "git checkout" operation. This option should be
> +was checked out using "git switch-branch" operation. This option should be
>  used by porcelains to accept this syntax anywhere a branch name is
>  expected, so they can act as if you typed the branch name. As an
>  exception note that, the ``previous checkout operation'' might result
> diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
> index aba4c5febe..0ceaa1173c 100644
> --- a/Documentation/git-format-patch.txt
> +++ b/Documentation/git-format-patch.txt
> @@ -416,7 +416,7 @@ One way to test if your MUA is set up correctly is:
>  * Apply it:
>  
>      $ git fetch <project> master:test-apply
> -    $ git checkout test-apply
> +    $ git switch-branch test-apply
>      $ git reset --hard
>      $ git am a.patch
>  
> diff --git a/Documentation/git-merge-base.txt b/Documentation/git-merge-base.txt
> index 9f07f4f6ed..1b25e5d530 100644
> --- a/Documentation/git-merge-base.txt
> +++ b/Documentation/git-merge-base.txt
> @@ -149,7 +149,7 @@ instead.
>  Discussion on fork-point mode
>  -----------------------------
>  
> -After working on the `topic` branch created with `git checkout -b
> +After working on the `topic` branch created with `git switch-branch -b
>  topic origin/master`, the history of remote-tracking branch
>  `origin/master` may have been rewound and rebuilt, leading to a
>  history of this shape:
> diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
> index 80793bad8d..fe10880633 100644
> --- a/Documentation/git-rebase.txt
> +++ b/Documentation/git-rebase.txt
> @@ -17,7 +17,7 @@ SYNOPSIS
>  DESCRIPTION
>  -----------
>  If <branch> is specified, 'git rebase' will perform an automatic
> -`git checkout <branch>` before doing anything else.  Otherwise
> +`git switch-branch <branch>` before doing anything else.  Otherwise
>  it remains on the current branch.
>  
>  If <upstream> is not specified, the upstream configured in
> diff --git a/Documentation/git-remote.txt b/Documentation/git-remote.txt
> index 0cad37fb81..044bbdb27c 100644
> --- a/Documentation/git-remote.txt
> +++ b/Documentation/git-remote.txt
> @@ -230,7 +230,7 @@ $ git branch -r
>    staging/master
>    staging/staging-linus
>    staging/staging-next
> -$ git checkout -b staging staging/master
> +$ git switch-branch -b staging staging/master
>  ...
>  ------------
>  
> diff --git a/Documentation/git-rerere.txt b/Documentation/git-rerere.txt
> index df310d2a58..fe9d21b395 100644
> --- a/Documentation/git-rerere.txt
> +++ b/Documentation/git-rerere.txt
> @@ -91,7 +91,7 @@ For such a test, you need to merge master and topic somehow.
>  One way to do it is to pull master into the topic branch:
>  
>  ------------
> -	$ git checkout topic
> +	$ git switch-branch topic
>  	$ git merge master
>  
>                o---*---o---+ topic
> @@ -113,10 +113,10 @@ the upstream might have been advanced since the test merge `+`,
>  in which case the final commit graph would look like this:
>  
>  ------------
> -	$ git checkout topic
> +	$ git switch-branch topic
>  	$ git merge master
>  	$ ... work on both topic and master branches
> -	$ git checkout master
> +	$ git switch-branch master
>  	$ git merge topic
>  
>                o---*---o---+---o---o topic
> @@ -136,11 +136,11 @@ merges, you could blow away the test merge, and keep building on
>  top of the tip before the test merge:
>  
>  ------------
> -	$ git checkout topic
> +	$ git switch-branch topic
>  	$ git merge master
>  	$ git reset --hard HEAD^ ;# rewind the test merge
>  	$ ... work on both topic and master branches
> -	$ git checkout master
> +	$ git switch-branch master
>  	$ git merge topic
>  
>                o---*---o-------o---o topic
> diff --git a/Documentation/git-reset.txt b/Documentation/git-reset.txt
> index 2dac95c71a..ca46b4c967 100644
> --- a/Documentation/git-reset.txt
> +++ b/Documentation/git-reset.txt
> @@ -149,9 +149,9 @@ See also the --amend option to linkgit:git-commit[1].
>  Undo a commit, making it a topic branch::
>  +
>  ------------
> -$ git branch topic/wip     <1>
> -$ git reset --hard HEAD~3  <2>
> -$ git checkout topic/wip   <3>
> +$ git branch topic/wip          <1>
> +$ git reset --hard HEAD~3       <2>
> +$ git switch-branch topic/wip   <3>
>  ------------
>  +
>  <1> You have made some commits, but realize they were premature
> @@ -232,13 +232,13 @@ working tree are not in any shape to be committed yet, but you
>  need to get to the other branch for a quick bugfix.
>  +
>  ------------
> -$ git checkout feature ;# you were working in "feature" branch and
> +$ git switch-branch feature ;# you were working in "feature" branch and
>  $ work work work       ;# got interrupted
>  $ git commit -a -m "snapshot WIP"                 <1>
> -$ git checkout master
> +$ git switch-branch master
>  $ fix fix fix
>  $ git commit ;# commit with real log
> -$ git checkout feature
> +$ git switch-branch feature
>  $ git reset --soft HEAD^ ;# go back to WIP state  <2>
>  $ git reset                                       <3>
>  ------------
> @@ -279,18 +279,18 @@ reset it while keeping the changes in your working tree.
>  +
>  ------------
>  $ git tag start
> -$ git checkout -b branch1
> +$ git switch-branch -b branch1
>  $ edit
>  $ git commit ...                            <1>
>  $ edit
> -$ git checkout -b branch2                   <2>
> +$ git switch-branch -b branch2              <2>
>  $ git reset --keep start                    <3>
>  ------------
>  +
>  <1> This commits your first edits in branch1.
>  <2> In the ideal world, you could have realized that the earlier
>      commit did not belong to the new topic when you created and switched
> -    to branch2 (i.e. "git checkout -b branch2 start"), but nobody is
> +    to branch2 (i.e. "git switch-branch -b branch2 start"), but nobody is
>      perfect.
>  <3> But you can use "reset --keep" to remove the unwanted commit after
>      you switched to "branch2".
> diff --git a/Documentation/git-revert.txt b/Documentation/git-revert.txt
> index 837707a8fd..e49dbbec83 100644
> --- a/Documentation/git-revert.txt
> +++ b/Documentation/git-revert.txt
> @@ -26,7 +26,7 @@ effect of some earlier commits (often only a faulty one).  If you want to
>  throw away all uncommitted changes in your working directory, you
>  should see linkgit:git-reset[1], particularly the `--hard` option.  If
>  you want to extract specific files as they were in another commit, you
> -should see linkgit:git-checkout[1], specifically the `git checkout
> +should see linkgit:git-checkout[1], specifically the `git checkout-files
>  <commit> -- <filename>` syntax.  Take care with these alternatives as
>  both will discard uncommitted changes in your working directory.
>  
> diff --git a/Documentation/git-stash.txt b/Documentation/git-stash.txt
> index 7ef8c47911..ea226979b1 100644
> --- a/Documentation/git-stash.txt
> +++ b/Documentation/git-stash.txt
> @@ -235,12 +235,12 @@ return to your original branch to make the emergency fix, like this:
>  +
>  ----------------------------------------------------------------
>  # ... hack hack hack ...
> -$ git checkout -b my_wip
> +$ git switch-branch -b my_wip
>  $ git commit -a -m "WIP"
> -$ git checkout master
> +$ git switch-branch master
>  $ edit emergency fix
>  $ git commit -a -m "Fix in a hurry"
> -$ git checkout my_wip
> +$ git switch-branch my_wip
>  $ git reset --soft HEAD^
>  # ... continue hacking ...
>  ----------------------------------------------------------------
> diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
> index b8392fc330..df62bd8019 100644
> --- a/Documentation/gitattributes.txt
> +++ b/Documentation/gitattributes.txt
> @@ -112,7 +112,7 @@ Checking-out and checking-in
>  
>  These attributes affect how the contents stored in the
>  repository are copied to the working tree files when commands
> -such as 'git checkout' and 'git merge' run.  They also affect how
> +such as 'git switch-branch' and 'git merge' run.  They also affect how
>  Git stores the contents you prepare in the working tree in the
>  repository upon 'git add' and 'git commit'.
>  
> diff --git a/Documentation/gitcli.txt b/Documentation/gitcli.txt
> index 592e06d839..0ad4869f2c 100644
> --- a/Documentation/gitcli.txt
> +++ b/Documentation/gitcli.txt
> @@ -47,8 +47,8 @@ disambiguating `--` at appropriate places.
>     things:
>  +
>  --------------------------------
> -$ git checkout -- *.c
> -$ git checkout -- \*.c
> +$ git checkout-files -- *.c
> +$ git checkout-files -- \*.c
>  --------------------------------
>  +
>  The former lets your shell expand the fileglob, and you are asking
> diff --git a/Documentation/gitcore-tutorial.txt b/Documentation/gitcore-tutorial.txt
> index e29a9effcc..49a8b5aa52 100644
> --- a/Documentation/gitcore-tutorial.txt
> +++ b/Documentation/gitcore-tutorial.txt
> @@ -741,7 +741,7 @@ used earlier, and create a branch in it. You do that by simply just
>  saying that you want to check out a new branch:
>  
>  ------------
> -$ git checkout -b mybranch
> +$ git branch mybranch
>  ------------
>  
>  will create a new branch based at the current `HEAD` position, and switch
> @@ -755,7 +755,7 @@ just telling 'git checkout' what the base of the checkout would be.
>  In other words, if you have an earlier tag or branch, you'd just do
>  
>  ------------
> -$ git checkout -b mybranch earlier-commit
> +$ git switch-branch -b mybranch earlier-commit
>  ------------
>  
>  and it would create the new branch `mybranch` at the earlier commit,
> @@ -765,7 +765,7 @@ and check out the state at that time.
>  You can always just jump back to your original `master` branch by doing
>  
>  ------------
> -$ git checkout master
> +$ git switch-branch master
>  ------------
>  
>  (or any other branch-name, for that matter) and if you forget which
> @@ -794,7 +794,7 @@ $ git branch <branchname> [startingpoint]
>  
>  which will simply _create_ the branch, but will not do anything further.
>  You can then later -- once you decide that you want to actually develop
> -on that branch -- switch to that branch with a regular 'git checkout'
> +on that branch -- switch to that branch with a regular 'git switch-branch
>  with the branchname as the argument.
>  
>  
> @@ -808,7 +808,7 @@ being the same as the original `master` branch, let's make sure we're in
>  that branch, and do some work there.
>  
>  ------------------------------------------------
> -$ git checkout mybranch
> +$ git switch-branch mybranch
>  $ echo "Work, work, work" >>hello
>  $ git commit -m "Some work." -i hello
>  ------------------------------------------------
> @@ -825,7 +825,7 @@ does some work in the original branch, and simulate that by going back
>  to the master branch, and editing the same file differently there:
>  
>  ------------
> -$ git checkout master
> +$ git switch-branch master
>  ------------
>  
>  Here, take a moment to look at the contents of `hello`, and notice how they
> @@ -958,7 +958,7 @@ to the `master` branch. Let's go back to `mybranch`, and run
>  'git merge' to get the "upstream changes" back to your branch.
>  
>  ------------
> -$ git checkout mybranch
> +$ git switch-branch mybranch
>  $ git merge -m "Merge upstream changes." master
>  ------------
>  
> @@ -1133,9 +1133,9 @@ Remember, before running 'git merge', our `master` head was at
>  work." commit.
>  
>  ------------
> -$ git checkout mybranch
> +$ git switch-branch mybranch
>  $ git reset --hard master^2
> -$ git checkout master
> +$ git switch-branch master
>  $ git reset --hard master^
>  ------------
>  
> diff --git a/Documentation/giteveryday.txt b/Documentation/giteveryday.txt
> index 9f2528fc8c..861b2bb616 100644
> --- a/Documentation/giteveryday.txt
> +++ b/Documentation/giteveryday.txt
> @@ -80,9 +80,9 @@ $ git tag v2.43 <2>
>  Create a topic branch and develop.::
>  +
>  ------------
> -$ git checkout -b alsa-audio <1>
> +$ git branch alsa-audio <1>
>  $ edit/compile/test
> -$ git checkout -- curses/ux_audio_oss.c <2>
> +$ git checkout-files -- curses/ux_audio_oss.c <2>
>  $ git add curses/ux_audio_alsa.c <3>
>  $ edit/compile/test
>  $ git diff HEAD <4>
> @@ -90,7 +90,7 @@ $ git commit -a -s <5>
>  $ edit/compile/test
>  $ git diff HEAD^ <6>
>  $ git commit -a --amend <7>
> -$ git checkout master <8>
> +$ git switch-branch master <8>
>  $ git merge alsa-audio <9>
>  $ git log --since='3 days ago' <10>
>  $ git log v2.43.. curses/ <11>
> @@ -148,11 +148,11 @@ Clone the upstream and work on it.  Feed changes to upstream.::
>  ------------
>  $ git clone git://git.kernel.org/pub/scm/.../torvalds/linux-2.6 my2.6
>  $ cd my2.6
> -$ git checkout -b mine master <1>
> +$ git switch-branch -b mine master <1>
>  $ edit/compile/test; git commit -a -s <2>
>  $ git format-patch master <3>
>  $ git send-email --to="person <email@example.com>" 00*.patch <4>
> -$ git checkout master <5>
> +$ git switch-branch master <5>
>  $ git pull <6>
>  $ git log -p ORIG_HEAD.. arch/i386 include/asm-i386 <7>
>  $ git ls-remote --heads http://git.kernel.org/.../jgarzik/libata-dev.git <8>
> @@ -194,7 +194,7 @@ satellite$ edit/compile/test/commit
>  satellite$ git push origin <4>
>  
>  mothership$ cd frotz
> -mothership$ git checkout master
> +mothership$ git switch-branch master
>  mothership$ git merge satellite/master <5>
>  ------------
>  +
> @@ -216,7 +216,7 @@ machine into the master branch.
>  Branch off of a specific tag.::
>  +
>  ------------
> -$ git checkout -b private2.6.14 v2.6.14 <1>
> +$ git switch-branch -b private2.6.14 v2.6.14 <1>
>  $ edit/compile/test; git commit -a
>  $ git checkout master
>  $ git cherry-pick v2.6.14..private2.6.14 <2>
> @@ -274,14 +274,14 @@ $ mailx <3>
>  & s 2 3 4 5 ./+to-apply
>  & s 7 8 ./+hold-linus
>  & q
> -$ git checkout -b topic/one master
> +$ git switch-branch -b topic/one master
>  $ git am -3 -i -s ./+to-apply <4>
>  $ compile/test
> -$ git checkout -b hold/linus && git am -3 -i -s ./+hold-linus <5>
> -$ git checkout topic/one && git rebase master <6>
> -$ git checkout pu && git reset --hard next <7>
> +$ git switch-branch -b hold/linus && git am -3 -i -s ./+hold-linus <5>
> +$ git switch-branch topic/one && git rebase master <6>
> +$ git switch-branch pu && git reset --hard next <7>
>  $ git merge topic/one topic/two && git merge hold/linus <8>
> -$ git checkout maint
> +$ git switch-branch maint
>  $ git cherry-pick master~4 <9>
>  $ compile/test
>  $ git tag -s -m "GIT 0.99.9x" v0.99.9x <10>
> diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt
> index 959044347e..3939ec774a 100644
> --- a/Documentation/githooks.txt
> +++ b/Documentation/githooks.txt
> @@ -166,7 +166,7 @@ worktree.  The hook is given three parameters: the ref of the previous HEAD,
>  the ref of the new HEAD (which may or may not have changed), and a flag
>  indicating whether the checkout was a branch checkout (changing branches,
>  flag=1) or a file checkout (retrieving a file from the index, flag=0).
> -This hook cannot affect the outcome of `git checkout`.
> +This hook cannot affect the outcome of `git switch-branch` or `git checkout`.
>  
>  It is also run after linkgit:git-clone[1], unless the `--no-checkout` (`-n`) option is
>  used. The first parameter given to the hook is the null-ref, the second the
> @@ -402,7 +402,8 @@ exit with a zero status.
>  For example, the hook can simply run `git read-tree -u -m HEAD "$1"`
>  in order to emulate `git fetch` that is run in the reverse direction
>  with `git push`, as the two-tree form of `git read-tree -u -m` is
> -essentially the same as `git checkout` that switches branches while
> +essentially the same as `git switch-branch` or `git checkout`
> +that switches branches while
>  keeping the local changes in the working tree that do not interfere
>  with the difference between the branches.
>  
> diff --git a/Documentation/gittutorial-2.txt b/Documentation/gittutorial-2.txt
> index e0976f6017..125213d951 100644
> --- a/Documentation/gittutorial-2.txt
> +++ b/Documentation/gittutorial-2.txt
> @@ -376,7 +376,7 @@ Changes to be committed:
>  
>  Changes not staged for commit:
>    (use "git add <file>..." to update what will be committed)
> -  (use "git checkout -- <file>..." to discard changes in working directory)
> +  (use "git checkout-files -- <file>..." to discard changes in working directory)
>  
>  	modified:   file.txt
>  
> diff --git a/Documentation/gittutorial.txt b/Documentation/gittutorial.txt
> index 242de31cb6..396e55c191 100644
> --- a/Documentation/gittutorial.txt
> +++ b/Documentation/gittutorial.txt
> @@ -207,7 +207,7 @@ automatically.  The asterisk marks the branch you are currently on;
>  type
>  
>  ------------------------------------------------
> -$ git checkout experimental
> +$ git switch-branch experimental
>  ------------------------------------------------
>  
>  to switch to the experimental branch.  Now edit a file, commit the
> @@ -216,7 +216,7 @@ change, and switch back to the master branch:
>  ------------------------------------------------
>  (edit file)
>  $ git commit -a
> -$ git checkout master
> +$ git switch-branch master
>  ------------------------------------------------
>  
>  Check that the change you made is no longer visible, since it was
> diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
> index 72daa20e76..f55502cd50 100644
> --- a/Documentation/revisions.txt
> +++ b/Documentation/revisions.txt
> @@ -115,7 +115,7 @@ Here's an example to make it more clear:
>  ------------------------------
>  $ git config push.default current
>  $ git config remote.pushdefault myfork
> -$ git checkout -b mybranch origin/master
> +$ git switch-branch -b mybranch origin/master
>  
>  $ git rev-parse --symbolic-full-name @{upstream}
>  refs/remotes/origin/master
> diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
> index eff7890274..56397e93d4 100644
> --- a/Documentation/user-manual.txt
> +++ b/Documentation/user-manual.txt
> @@ -125,7 +125,7 @@ Create a new branch head pointing to one of these versions and check it
>  out using linkgit:git-checkout[1]:
>  
>  ------------------------------------------------
> -$ git checkout -b new v2.6.13
> +$ git switch-branch -b new v2.6.13
>  ------------------------------------------------
>  
>  The working directory then reflects the contents that the project had
> @@ -282,10 +282,10 @@ a summary of the commands:
>  	this command will fail with a warning.
>  `git branch -D <branch>`::
>  	delete the branch `<branch>` irrespective of its merged status.
> -`git checkout <branch>`::
> +`git switch-branch <branch>`::
>  	make the current branch `<branch>`, updating the working
>  	directory to reflect the version referenced by `<branch>`.
> -`git checkout -b <new> <start-point>`::
> +`git switch-branch -b <new> <start-point>`::
>  	create a new branch `<new>` referencing `<start-point>`, and
>  	check it out.
>  
> @@ -302,12 +302,12 @@ ref: refs/heads/master
>  Examining an old version without creating a new branch
>  ------------------------------------------------------
>  
> -The `git checkout` command normally expects a branch head, but will also
> +The `git switch-branch` command normally expects a branch head, but will also
>  accept an arbitrary commit; for example, you can check out the commit
>  referenced by a tag:
>  
>  ------------------------------------------------
> -$ git checkout v2.6.17
> +$ git switch-branch v2.6.17
>  Note: checking out 'v2.6.17'.
>  
>  You are in 'detached HEAD' state. You can look around, make experimental
> @@ -317,7 +317,7 @@ state without impacting any branches by performing another checkout.
>  If you want to create a new branch to retain commits you create, you may
>  do so (now or later) by using -b with the checkout command again. Example:
>  
> -  git checkout -b new_branch_name
> +  git switch-branch -b new_branch_name
>  
>  HEAD is now at 427abfa Linux v2.6.17
>  ------------------------------------------------
> @@ -373,7 +373,7 @@ You might want to build on one of these remote-tracking branches
>  on a branch of your own, just as you would for a tag:
>  
>  ------------------------------------------------
> -$ git checkout -b my-todo-copy origin/todo
> +$ git switch-branch -b my-todo-copy origin/todo
>  ------------------------------------------------
>  
>  You can also check out `origin/todo` directly to examine it or
> @@ -1523,12 +1523,12 @@ Checking out an old version of a file
>  
>  In the process of undoing a previous bad change, you may find it
>  useful to check out an older version of a particular file using
> -linkgit:git-checkout[1].  We've used `git checkout` before to switch
> +linkgit:git-checkout[1].  We've used `git switch-branch` before to switch
>  branches, but it has quite different behavior if it is given a path
>  name: the command
>  
>  -------------------------------------------------
> -$ git checkout HEAD^ path/to/file
> +$ git checkout-files HEAD^ path/to/file
>  -------------------------------------------------
>  
>  replaces path/to/file by the contents it had in the commit HEAD^, and
> @@ -2211,8 +2211,8 @@ $ git branch --track release origin/master
>  These can be easily kept up to date using linkgit:git-pull[1].
>  
>  -------------------------------------------------
> -$ git checkout test && git pull
> -$ git checkout release && git pull
> +$ git switch-branch test && git pull
> +$ git switch-branch release && git pull
>  -------------------------------------------------
>  
>  Important note!  If you have any local changes in these branches, then
> @@ -2264,7 +2264,7 @@ tested changes
>  2) help future bug hunters that use `git bisect` to find problems
>  
>  -------------------------------------------------
> -$ git checkout -b speed-up-spinlocks v2.6.35
> +$ git switch-branch -b speed-up-spinlocks v2.6.35
>  -------------------------------------------------
>  
>  Now you apply the patch(es), run some tests, and commit the change(s).  If
> @@ -2279,7 +2279,7 @@ When you are happy with the state of this change, you can merge it into the
>  "test" branch in preparation to make it public:
>  
>  -------------------------------------------------
> -$ git checkout test && git merge speed-up-spinlocks
> +$ git switch-branch test && git merge speed-up-spinlocks
>  -------------------------------------------------
>  
>  It is unlikely that you would have any conflicts here ... but you might if you
> @@ -2291,7 +2291,7 @@ see the value of keeping each patch (or patch series) in its own branch.  It
>  means that the patches can be moved into the `release` tree in any order.
>  
>  -------------------------------------------------
> -$ git checkout release && git merge speed-up-spinlocks
> +$ git switch-branch release && git merge speed-up-spinlocks
>  -------------------------------------------------
>  
>  After a while, you will have a number of branches, and despite the
> @@ -2358,7 +2358,7 @@ Here are some of the scripts that simplify all this even further.
>  
>  case "$1" in
>  test|release)
> -	git checkout $1 && git pull . origin
> +	git switch-branch $1 && git pull . origin
>  	;;
>  origin)
>  	before=$(git rev-parse refs/remotes/origin/master)
> @@ -2400,7 +2400,7 @@ test|release)
>  		echo $1 already merged into $2 1>&2
>  		exit 1
>  	fi
> -	git checkout $2 && git pull . $1
> +	git switch-branch $2 && git pull . $1
>  	;;
>  *)
>  	usage
> @@ -2512,7 +2512,7 @@ Suppose that you create a branch `mywork` on a remote-tracking branch
>  `origin`, and create some commits on top of it:
>  
>  -------------------------------------------------
> -$ git checkout -b mywork origin
> +$ git switch-branch -b mywork origin
>  $ vi file.txt
>  $ git commit
>  $ vi otherfile.txt
> @@ -2552,7 +2552,7 @@ commits without any merges, you may instead choose to use
>  linkgit:git-rebase[1]:
>  
>  -------------------------------------------------
> -$ git checkout mywork
> +$ git switch-branch mywork
>  $ git rebase origin
>  -------------------------------------------------
>  
> @@ -3668,13 +3668,13 @@ change within the submodule, and then update the superproject to reference the
>  new commit:
>  
>  -------------------------------------------------
> -$ git checkout master
> +$ git switch-branch master
>  -------------------------------------------------
>  
>  or
>  
>  -------------------------------------------------
> -$ git checkout -b fix-up
> +$ git switch-branch -b fix-up
>  -------------------------------------------------
>  
>  then
> @@ -4194,7 +4194,7 @@ start.
>  A good place to start is with the contents of the initial commit, with:
>  
>  ----------------------------------------------------
> -$ git checkout e83c5163
> +$ git switch-branch e83c5163
>  ----------------------------------------------------
>  
>  The initial revision lays the foundation for almost everything Git has
> @@ -4437,10 +4437,10 @@ Managing branches
>  -----------------
>  
>  -----------------------------------------------
> -$ git branch	     # list all local branches in this repo
> -$ git checkout test  # switch working directory to branch "test"
> -$ git branch new     # create branch "new" starting at current HEAD
> -$ git branch -d new  # delete branch "new"
> +$ git branch			# list all local branches in this repo
> +$ git switch-branch test	# switch working directory to branch "test"
> +$ git branch new		# create branch "new" starting at current HEAD
> +$ git branch -d new		# delete branch "new"
>  -----------------------------------------------
>  
>  Instead of basing a new branch on current HEAD (the default), use:
> @@ -4456,7 +4456,7 @@ $ git branch new test~10 # ten commits before tip of branch "test"
>  Create and switch to a new branch at the same time:
>  
>  -----------------------------------------------
> -$ git checkout -b new v2.6.15
> +$ git switch-branch -b new v2.6.15
>  -----------------------------------------------
>  
>  Update and examine branches from the repository you cloned from:
> @@ -4467,7 +4467,7 @@ $ git branch -r		# list
>    origin/master
>    origin/next
>    ...
> -$ git checkout -b masterwork origin/master
> +$ git switch-branch -b masterwork origin/master
>  -----------------------------------------------
>  
>  Fetch a branch from a different repository, and give it a new
> diff --git a/advice.c b/advice.c
> index 5f35656409..1befdb2163 100644
> --- a/advice.c
> +++ b/advice.c
> @@ -195,7 +195,7 @@ void detach_advice(const char *new_name)
>  	"state without impacting any branches by performing another checkout.\n\n"
>  	"If you want to create a new branch to retain commits you create, you may\n"
>  	"do so (now or later) by using -b with the checkout command again. Example:\n\n"
> -	"  git checkout -b <new-branch-name>\n\n");
> +	"  git branch <new-branch-name>\n\n");
>  
>  	fprintf(stderr, fmt, new_name);
>  }
> diff --git a/sha1-name.c b/sha1-name.c
> index faa60f69e3..4e4e14a45c 100644
> --- a/sha1-name.c
> +++ b/sha1-name.c
> @@ -771,7 +771,7 @@ static int get_oid_basic(const char *str, int len, struct object_id *oid,
>  	"because it will be ignored when you just specify 40-hex. These refs\n"
>  	"may be created by mistake. For example,\n"
>  	"\n"
> -	"  git checkout -b $br $(git rev-parse ...)\n"
> +	"  git switch-branch -b $br $(git rev-parse ...)\n"
>  	"\n"
>  	"where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
>  	"examine these refs and maybe delete them. Turn this message off by\n"
> diff --git a/wt-status.c b/wt-status.c
> index a24711374c..6266683926 100644
> --- a/wt-status.c
> +++ b/wt-status.c
> @@ -224,7 +224,7 @@ static void wt_longstatus_print_dirty_header(struct wt_status *s,
>  		status_printf_ln(s, c, _("  (use \"git add <file>...\" to update what will be committed)"));
>  	else
>  		status_printf_ln(s, c, _("  (use \"git add/rm <file>...\" to update what will be committed)"));
> -	status_printf_ln(s, c, _("  (use \"git checkout -- <file>...\" to discard changes in working directory)"));
> +	status_printf_ln(s, c, _("  (use \"git checkout-files <file>...\" to discard changes in working directory)"));
>  	if (has_dirty_submodules)
>  		status_printf_ln(s, c, _("  (commit or discard the untracked or modified content in submodules)"));
>  	status_printf_ln(s, c, "%s", "");

>
> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
>
> > The assumption made is here
> >
> > - "git checkout" is a horrible monster that should only be touched
> >   with a two-meter pole
> >
> > - there are other commands that can achieve the same thing
>
> Thanks for clearly spelling out the assumptions.  It is good that
> this step cames at the end, as the earlier 6 steps looked reasonable
> to me.

> I see my deliberate attempt to provoke has failed :D Giving your view
> of the new commands as "training wheels", I take it we still should
> make them visible as much as possible, but we just not try to hide
> "git checkout" as much (e.g. we mention both new and old commands,
> instead of just mentioning the new one, when suggesting something)?

>
> v2 is just a bit better to look at than v1. This is by no means final.
> If you think the command name is bad, the default behavior should
> change, or something else, speak up. It's still very "RFC".
>
> v2 breaks down the giant patch in v1 and starts adding some changes in
> these new commands:
>
> - restore-paths is renamed to checkout-paths. I wrote I didn't like
>   "checkout" because of completion conflict. But who am I kidding,
>   I'll use aliases anyway. "-files" instead of "-paths" because we
>   already have ls-files.
> - both commands will not accept no arguments. There is no "git
>   checkout" equivalent.
> - ambiguation rules are now aware that "switch-branch" for example
>   can't take pathspec...

> should we do
> something about detached HEAD in this switch-branch command (or
> whatever its name will be)?
>
> This is usually a confusing concept to new users

>
> On Wed, Nov 28, 2018 at 9:01 PM Duy Nguyen <pclouds@gmail.com> wrote:
> > should we do
> > something about detached HEAD in this switch-branch command (or
> > whatever its name will be)?
> >
> > This is usually a confusing concept to new users
>
> And it just occurred to me that perhaps we should call this "unnamed
> branch" (at least at high UI level) instead of detached HEAD. It is
> technically not as accurate, but much better to understand.

>
> On Wed, Nov 28, 2018 at 12:09 PM Duy Nguyen <pclouds@gmail.com> wrote:
> >
> > On Wed, Nov 28, 2018 at 9:01 PM Duy Nguyen <pclouds@gmail.com> wrote:
> > > should we do
> > > something about detached HEAD in this switch-branch command (or
> > > whatever its name will be)?
> > >
> > > This is usually a confusing concept to new users
> >
> > And it just occurred to me that perhaps we should call this "unnamed
> > branch" (at least at high UI level) instead of detached HEAD. It is
> > technically not as accurate, but much better to understand.
>
> or 'direct' branch?

>
> On Wed, Nov 28, 2018 at 9:30 PM Stefan Beller <sbeller@google.com> wrote:
> >
> > On Wed, Nov 28, 2018 at 12:09 PM Duy Nguyen <pclouds@gmail.com> wrote:
> > >
> > > On Wed, Nov 28, 2018 at 9:01 PM Duy Nguyen <pclouds@gmail.com> wrote:
> > > > should we do
> > > > something about detached HEAD in this switch-branch command (or
> > > > whatever its name will be)?
> > > >
> > > > This is usually a confusing concept to new users
> > >
> > > And it just occurred to me that perhaps we should call this "unnamed
> > > branch" (at least at high UI level) instead of detached HEAD. It is
> > > technically not as accurate, but much better to understand.
> >
> > or 'direct' branch?
>
> makes me think, what is an indirect branch?

> On Wed, Nov 28, 2018 at 9:01 PM Duy Nguyen <pclouds@gmail.com> wrote:
>> should we do
>> something about detached HEAD in this switch-branch command (or
>> whatever its name will be)?
>>
>> This is usually a confusing concept to new users
>
> And it just occurred to me that perhaps we should call this "unnamed
> branch" (at least at high UI level) instead of detached HEAD. It is
> technically not as accurate, but much better to understand.

> +	if (!opts->implicit_detach &&
> +	    !opts->new_branch &&
> +	    !opts->new_branch_force &&
> +	    new_branch_info->name &&
> +	    !new_branch_info->path)
> +		die(_("a branch is expected, got %s"), new_branch_info->name);

>
> On Thu, Nov 29, 2018 at 10:58:46PM +0100, Nguyễn Thái Ngọc Duy wrote:
> > +     if (!opts->implicit_detach &&
> > +         !opts->new_branch &&
> > +         !opts->new_branch_force &&
> > +         new_branch_info->name &&
> > +         !new_branch_info->path)
> > +             die(_("a branch is expected, got %s"), new_branch_info->name);
>
> Wouldn't it be nice to give more context here, for example the symbolic
> reference that the name actually points to? When expereimenting with the
> feature and trying to switch to a tag, it refuses with
> "a branch is expected, got v1.2.0". I personally would prefer something
> more like "a branch is expected, got v1.2.0 that resolved to
> refs/tags/v1.2.0", so I get "oh, yeah, that is actually a tag ...". Does
> this seem worthwhile to dig deeper into? A quick glance left me a bit
> puzzled, I admit.

> good old "git checkout" command is still here and will be until all
> (or most of users) are sick of it.
>
> See the new man pages for the final design of these commands. The
> actual implementation though is still pretty much the same as "git
> checkout". Following patches will adjust their behavior to match the
> man pages.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  .gitignore                          |   2 +
>  Documentation/git-checkout.txt      |   5 +
>  Documentation/git-restore-files.txt | 167 ++++++++++++++++
>  Documentation/git-switch-branch.txt | 289 ++++++++++++++++++++++++++++
>  Makefile                            |   2 +
>  builtin.h                           |   2 +
>  builtin/checkout.c                  |  84 ++++++--
>  command-list.txt                    |   2 +
>  git.c                               |   2 +
>  9 files changed, 543 insertions(+), 12 deletions(-)
>  create mode 100644 Documentation/git-restore-files.txt
>  create mode 100644 Documentation/git-switch-branch.txt
>
> diff --git a/.gitignore b/.gitignore
> index 0d77ea5894..c63dcb1427 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -143,6 +143,7 @@
>  /git-request-pull
>  /git-rerere
>  /git-reset
> +/git-restore-files

>  /git-rev-list
>  /git-rev-parse
>  /git-revert
> @@ -167,6 +168,7 @@
>  /git-submodule
>  /git-submodule--helper
>  /git-svn
> +/git-switch-branch
>  /git-symbolic-ref
>  /git-tag
>  /git-unpack-file
> diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
> index 25887a6087..25ec7f508f 100644
> --- a/Documentation/git-checkout.txt
> +++ b/Documentation/git-checkout.txt
> @@ -406,6 +406,11 @@ $ edit frotz
>  $ git add frotz
>  ------------
>
> +SEE ALSO
> +--------
> +linkgit:git-switch-branch[1]
> +linkgit:git-restore-files[1]
> +
>  GIT
>  ---
>  Part of the linkgit:git[1] suite
> diff --git a/Documentation/git-restore-files.txt b/Documentation/git-restore-files.txt
> new file mode 100644
> index 0000000000..03c1250ad0
> --- /dev/null
> +++ b/Documentation/git-restore-files.txt
> @@ -0,0 +1,167 @@
> +git-restore-files(1)
> +====================
> +
> +NAME
> +----
> +git-restore-files - Restore working tree files
> +
> +SYNOPSIS
> +--------
> +[verse]
> +'git restore-files' [-f|--ours|--theirs|-m|--conflict=<style>] [--from=<tree-ish>] <pathspec>...

> +'git restore-files' (-p|--patch) [--from=<tree-ish>] [<pathspec>...]
> +
> +DESCRIPTION
> +-----------
> +Updates files in the working tree to match the version in the index
> +or the specified tree.
> +
> +'git restore-files' [--from=<tree-ish>] <pathspec>...::

> +
> +       Overwrite paths in the working tree by replacing with the
> +       contents in the index or in the <tree-ish> (most often a
> +       commit).  When a <tree-ish> is given, the paths that
> +       match the <pathspec> are updated both in the index and in
> +       the working tree.

> ++
> +The index may contain unmerged entries because of a previous failed merge.
> +By default, if you try to check out such an entry from the index, the
> +checkout operation will fail and nothing will be checked out.
> +Using `-f` will ignore these unmerged entries.  The contents from a
> +specific side of the merge can be checked out of the index by
> +using `--ours` or `--theirs`.  With `-m`, changes made to the working tree
> +file can be discarded to re-create the original conflicted merge result.
> +
> +'git restore-files' (-p|--patch) [--from=<tree-ish>] [<pathspec>...]::
> +       This is similar to the "check out paths to the working tree
> +       from either the index or from a tree-ish" mode described
> +       above, but lets you use the interactive interface to show
> +       the "diff" output and choose which hunks to use in the
> +       result.  See below for the description of `--patch` option.
> +
> +OPTIONS
> +-------
> +-q::
> +--quiet::
> +       Quiet, suppress feedback messages.
> +
> +--[no-]progress::
> +       Progress status is reported on the standard error stream
> +       by default when it is attached to a terminal, unless `--quiet`
> +       is specified. This flag enables progress reporting even if not
> +       attached to a terminal, regardless of `--quiet`.
> +
> +-f::
> +--force::
> +       Do not fail upon unmerged entries; instead, unmerged entries
> +       are ignored.

> +--ours::
> +--theirs::
> +       Check out stage #2 ('ours') or #3 ('theirs') for unmerged
> +       paths.
> ++
> +Note that during `git rebase` and `git pull --rebase`, 'ours' and
> +'theirs' may appear swapped; `--ours` gives the version from the
> +branch the changes are rebased onto, while `--theirs` gives the
> +version from the branch that holds your work that is being rebased.
> ++
> +This is because `rebase` is used in a workflow that treats the
> +history at the remote as the shared canonical one, and treats the
> +work done on the branch you are rebasing as the third-party work to
> +be integrated, and you are temporarily assuming the role of the
> +keeper of the canonical history during the rebase.  As the keeper of
> +the canonical history, you need to view the history from the remote
> +as `ours` (i.e. "our shared canonical history"), while what you did
> +on your side branch as `theirs` (i.e. "one contributor's work on top
> +of it").

> +
> +--ignore-skip-worktree-bits::
> +       In sparse checkout mode, update only entries matched by
> +       <paths> and sparse patterns in
> +       $GIT_DIR/info/sparse-checkout. This option ignores the sparse
> +       patterns and adds back any files in <paths>.

> +
> +-m::
> +--merge::
> +       When checking out paths from the index, this option lets you
> +       recreate the conflicted merge in the specified paths.
> +
> +--conflict=<style>::
> +       The same as --merge option above, but changes the way the
> +       conflicting hunks are presented, overriding the
> +       merge.conflictStyle configuration variable.  Possible values are
> +       "merge" (default) and "diff3" (in addition to what is shown by
> +       "merge" style, shows the original contents).
> +
> +-p::
> +--patch::
> +       Interactively select hunks in the difference between the
> +       <tree-ish> (or the index, if unspecified) and the working
> +       tree.  The chosen hunks are then applied in reverse to the
> +       working tree (and if a <tree-ish> was specified, the index).
> ++
> +This means that you can use `git restore-files -p` to selectively
> +discard edits from your current working tree. See the ``Interactive
> +Mode'' section of linkgit:git-add[1] to learn how to operate the
> +`--patch` mode.
> +
> +--[no-]recurse-submodules::
> +       Using --recurse-submodules will update the content of all initialized
> +       submodules according to the commit recorded in the superproject. If
> +       local modifications in a submodule would be overwritten the checkout
> +       will fail unless `-f` is used. If nothing (or --no-recurse-submodules)
> +       is used, the work trees of submodules will not be updated.
> +       Just like linkgit:git-submodule[1], this will detach the
> +       submodules HEAD.
> +
> +<tree-ish>::
> +       Tree to checkout from (when paths are given). If not specified,
> +       the index will be used.

> +
> +EXAMPLES
> +--------
> +
> +. The following sequence checks out the `master` branch, reverts
> +the `Makefile` to two revisions back, deletes hello.c by
> +mistake, and gets it back from the index.
> ++
> +------------
> +$ git switch-branch master                    <1>
> +$ git restore-files --from master~2 Makefile  <2>
> +$ rm -f hello.c
> +$ git restore-files hello.c                   <3>
> +------------
> ++
> +<1> switch branch
> +<2> take a file out of another commit
> +<3> restore hello.c from the index
> ++

> +If you want to check out _all_ C source files out of the index,
> +you can say
> ++
> +------------
> +$ git restore-files '*.c'
> +------------
> ++
> +Note the quotes around `*.c`.  The file `hello.c` will also be
> +checked out, even though it is no longer in the working tree,
> +because the file globbing is used to match entries in the index
> +(not in the working tree by the shell).

> ++
> +If you have an unfortunate branch that is named `hello.c`, this
> +step would be confused as an instruction to switch to that branch.
> +You should instead write:
> ++
> +------------
> +$ git restore-files hello.c
> +------------

> +
> +SEE ALSO
> +--------
> +linkgit:git-checkout[1]
> +
> +GIT
> +---
> +Part of the linkgit:git[1] suite

> diff --git a/Documentation/git-switch-branch.txt b/Documentation/git-switch-branch.txt
> new file mode 100644
> index 0000000000..d5bf5cb37d
> --- /dev/null
> +++ b/Documentation/git-switch-branch.txt
> @@ -0,0 +1,289 @@
> +git-switch-branch(1)
> +====================
> +
> +NAME
> +----
> +git-switch-branch - Switch branches
> +
> +SYNOPSIS
> +--------
> +[verse]
> +'git switch-branch' [-q] [-f] [-m] <branch>
> +'git switch-branch' [-q] [-f] [-m] --detach [<commit>]
> +'git switch-branch' [-q] [-f] [-m] [[-b|-B|--orphan] <new_branch>] [<start_point>]

> +
> +DESCRIPTION
> +-----------
> +Switch to a specified branch and update files in the working tree to
> +match it.
> +
> +'git switch-branch' <branch>::
> +       To prepare for working on <branch>, switch to it by updating
> +       the index and the files in the working tree. Local
> +       modifications to the files in the working tree are kept, so
> +       that they can be committed to the <branch>.
> ++
> +If <branch> is not found but there does exist a tracking branch in
> +exactly one remote (call it <remote>) with a matching name, treat as
> +equivalent to
> ++
> +------------
> +$ git switch-branch -b <branch> --track <remote>/<branch>
> +------------

> ++
> +If the branch exists in multiple remotes and one of them is named by
> +the `checkout.defaultRemote` configuration variable, we'll use that
> +one for the purposes of disambiguation, even if the `<branch>` isn't
> +unique across all remotes. Set it to
> +e.g. `checkout.defaultRemote=origin` to always checkout remote
> +branches from there if `<branch>` is ambiguous but exists on the
> +'origin' remote. See also `checkout.defaultRemote` in
> +linkgit:git-config[1].

> +
> +'git switch-branch' -c|-C <new_branch> [<start_point>]::
> +
> +       Specifying `-c` causes a new branch to be created as if
> +       linkgit:git-branch[1] were called and then switched to. In
> +       this case you can use the `--track` or `--no-track` options,
> +       which will be passed to 'git branch'.  As a convenience,
> +       `--track` without `-c` implies branch creation; see the
> +       description of `--track` below.

> ++
> +If `-C` is given, <new_branch> is created if it doesn't exist;
> +otherwise, it is reset. This is the transactional equivalent of
> ++
> +------------
> +$ git branch -f <branch> [<start_point>]
> +$ git switch-branch <branch>
> +------------
> ++
> +that is to say, the branch is not reset/created unless "git
> +switch-branch" is successful.

> +
> +'git switch-branch' --detach [<commit>]::
> +
> +       Prepare to work on a unnamed branch on top of <commit> (see
> +       "DETACHED HEAD" section), and updating the index and the files
> +       in the working tree.  Local modifications to the files in the
> +       working tree are kept, so that the resulting working tree will
> +       be the state recorded in the commit plus the local
> +       modifications.
> ++
> +When the <commit> argument is a branch name, the `--detach` option can
> +be used to detach HEAD at the tip of the branch (`git switch-branch
> +<branch>` would check out that branch without detaching HEAD).
> ++
> +Omitting <commit> detaches HEAD at the tip of the current branch.
> +
> +OPTIONS
> +-------
> +-q::
> +--quiet::
> +       Quiet, suppress feedback messages.
> +
> +--[no-]progress::
> +       Progress status is reported on the standard error stream
> +       by default when it is attached to a terminal, unless `--quiet`
> +       is specified. This flag enables progress reporting even if not
> +       attached to a terminal, regardless of `--quiet`.
> +
> +-f::
> +--force::
> +       Proceed even if the index or the working tree differs from
> +       HEAD.  This is used to throw away local changes.

> +-c <new_branch>::
> +--create <new_branch>::
> +       Create a new branch named <new_branch> and start it at
> +       <start_point>; see linkgit:git-branch[1] for details.
> +
> +-C <new_branch>::
> +--force-create <new_branch>::
> +       Creates the branch <new_branch> and start it at <start_point>;
> +       if it already exists, then reset it to <start_point>. This is
> +       equivalent to running "git branch" with "-f"; see
> +       linkgit:git-branch[1] for details.

> +
> +-t::
> +--track::
> +       When creating a new branch, set up "upstream" configuration. See
> +       "--track" in linkgit:git-branch[1] for details.
> ++
> +If no `-c` option is given, the name of the new branch will be derived
> +from the remote-tracking branch, by looking at the local part of the
> +refspec configured for the corresponding remote, and then stripping
> +the initial part up to the "*".
> +This would tell us to use "hack" as the local branch when branching
> +off of "origin/hack" (or "remotes/origin/hack", or even
> +"refs/remotes/origin/hack").  If the given name has no slash, or the above
> +guessing results in an empty name, the guessing is aborted.  You can
> +explicitly give a name with `-c` in such a case.
> +
> +--no-track::
> +       Do not set up "upstream" configuration, even if the
> +       branch.autoSetupMerge configuration variable is true.

> +
> +--detach::
> +       Rather than checking out a branch to work on it, check out a
> +       commit for inspection and discardable experiments.
> +       This is the default behavior of "git checkout <commit>" when
> +       <commit> is not a branch name.  See the "DETACHED HEAD" section
> +       below for details.
> +
> +--orphan <new_branch>::
> +       Create a new 'orphan' branch, named <new_branch>, started from
> +       <start_point> and switch to it.  The first commit made on this

> +       new branch will have no parents and it will be the root of a new
> +       history totally disconnected from all the other branches and
> +       commits.
> ++
> +The index and the working tree are adjusted as if you had previously run
> +"git checkout <start_point>".  This allows you to start a new history
> +that records a set of paths similar to <start_point> by easily running
> +"git commit -a" to make the root commit.
> ++
> +This can be useful when you want to publish the tree from a commit
> +without exposing its full history. You might want to do this to publish
> +an open source branch of a project whose current tree is "clean", but
> +whose full history contains proprietary or otherwise encumbered bits of
> +code.
> ++
> +If you want to start a disconnected history that records a set of paths
> +that is totally different from the one of <start_point>, then you should
> +clear the index and the working tree right after creating the orphan
> +branch by running "git rm -rf ." from the top level of the working tree.
> +Afterwards you will be ready to prepare your new files, repopulating the
> +working tree, by copying them from elsewhere, extracting a tarball, etc.

> +-m::
> +--merge::
> +       If you have local modifications to one or more files that are
> +       different between the current branch and the branch to which
> +       you are switching, the command refuses to switch branches in
> +       order to preserve your modifications in context.  However,
> +       with this option, a three-way merge between the current
> +       branch, your working tree contents, and the new branch is
> +       done, and you will be on the new branch.
> ++
> +When a merge conflict happens, the index entries for conflicting
> +paths are left unmerged, and you need to resolve the conflicts
> +and mark the resolved paths with `git add` (or `git rm` if the merge
> +should result in deletion of the path).
> +
> +--conflict=<style>::
> +       The same as --merge option above, but changes the way the
> +       conflicting hunks are presented, overriding the
> +       merge.conflictStyle configuration variable.  Possible values are
> +       "merge" (default) and "diff3" (in addition to what is shown by
> +       "merge" style, shows the original contents).
> +
> +--ignore-other-worktrees::
> +       `git switch-branch` refuses when the wanted ref is already
> +       checked out by another worktree. This option makes it check
> +       the ref out anyway. In other words, the ref can be held by
> +       more than one worktree.

> +
> +--[no-]recurse-submodules::
> +       Using --recurse-submodules will update the content of all initialized
> +       submodules according to the commit recorded in the superproject. If
> +       local modifications in a submodule would be overwritten the checkout
> +       will fail unless `-f` is used. If nothing (or --no-recurse-submodules)
> +       is used, the work trees of submodules will not be updated.
> +       Just like linkgit:git-submodule[1], this will detach the
> +       submodules HEAD.
> +
> +<branch>::
> +       Branch to checkout; if it refers to a branch (i.e., a name that,
> +       when prepended with "refs/heads/", is a valid ref), then that
> +       branch is checked out. Otherwise, if it refers to a valid
> +       commit, your HEAD becomes "detached" and you are no longer on
> +       any branch (see below for details).

> ++
> +You can use the `"@{-N}"` syntax to refer to the N-th last
> +branch/commit checked out using "git checkout" operation. You may
> +also specify `-` which is synonymous to `"@{-1}`.
> ++
> +As a special case, you may use `"A...B"` as a shortcut for the
> +merge base of `A` and `B` if there is exactly one merge base. You can
> +leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.

> +
> +<new_branch>::
> +       Name for the new branch.
> +
> +<start_point>::
> +       The name of a commit at which to start the new branch; see
> +       linkgit:git-branch[1] for details. Defaults to HEAD.

> +
> +DETACHED HEAD
> +-------------
> +include::detach-head.txt[]
> +
> +EXAMPLES
> +--------
> +
> +. The following sequence checks out the `master` branch.
> ++
> +------------
> +$ git switch-branch master
> +------------
> ++
> +
> +. After working in the wrong branch, switching to the correct
> +branch would be done using:
> ++
> +------------
> +$ git switch-branch mytopic
> +------------
> ++
> +However, your "wrong" branch and correct "mytopic" branch may
> +differ in files that you have modified locally, in which case
> +the above checkout would fail like this:
> ++
> +------------
> +$ git switch-branch mytopic
> +error: You have local changes to 'frotz'; not switching branches.
> +------------
> ++
> +You can give the `-m` flag to the command, which would try a
> +three-way merge:
> ++
> +------------
> +$ git switch-branch -m mytopic
> +Auto-merging frotz
> +------------
> ++
> +After this three-way merge, the local modifications are _not_
> +registered in your index file, so `git diff` would show you what
> +changes you made since the tip of the new branch.
> +
> +. When a merge conflict happens during switching branches with
> +the `-m` option, you would see something like this:
> ++
> +------------
> +$ git switch-branch -m mytopic
> +Auto-merging frotz
> +ERROR: Merge conflict in frotz
> +fatal: merge program failed
> +------------
> ++
> +At this point, `git diff` shows the changes cleanly merged as in
> +the previous example, as well as the changes in the conflicted
> +files.  Edit and resolve the conflict and mark it resolved with
> +`git add` as usual:
> ++
> +------------
> +$ edit frotz
> +$ git add frotz
> +------------
> +
> +SEE ALSO
> +--------
> +linkgit:git-checkout[1]
> +
> +GIT
> +---
> +Part of the linkgit:git[1] suite
> diff --git a/Makefile b/Makefile
> index 1a44c811aa..f035dbab9e 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -777,9 +777,11 @@ BUILT_INS += git-format-patch$X
>  BUILT_INS += git-fsck-objects$X
>  BUILT_INS += git-init$X
>  BUILT_INS += git-merge-subtree$X
> +BUILT_INS += git-restore-files$X
>  BUILT_INS += git-show$X
>  BUILT_INS += git-stage$X
>  BUILT_INS += git-status$X
> +BUILT_INS += git-switch-branch$X
>  BUILT_INS += git-whatchanged$X
>
>  # what 'all' will build and 'install' will install in gitexecdir,
> diff --git a/builtin.h b/builtin.h
> index 6538932e99..01ed43ea69 100644
> --- a/builtin.h
> +++ b/builtin.h
> @@ -214,6 +214,7 @@ extern int cmd_remote_fd(int argc, const char **argv, const char *prefix);
>  extern int cmd_repack(int argc, const char **argv, const char *prefix);
>  extern int cmd_rerere(int argc, const char **argv, const char *prefix);
>  extern int cmd_reset(int argc, const char **argv, const char *prefix);
> +extern int cmd_restore_files(int argc, const char **argv, const char *prefix);
>  extern int cmd_rev_list(int argc, const char **argv, const char *prefix);
>  extern int cmd_rev_parse(int argc, const char **argv, const char *prefix);
>  extern int cmd_revert(int argc, const char **argv, const char *prefix);
> @@ -227,6 +228,7 @@ extern int cmd_show_index(int argc, const char **argv, const char *prefix);
>  extern int cmd_status(int argc, const char **argv, const char *prefix);
>  extern int cmd_stripspace(int argc, const char **argv, const char *prefix);
>  extern int cmd_submodule__helper(int argc, const char **argv, const char *prefix);
> +extern int cmd_switch_branch(int argc, const char **argv, const char *prefix);
>  extern int cmd_symbolic_ref(int argc, const char **argv, const char *prefix);
>  extern int cmd_tag(int argc, const char **argv, const char *prefix);
>  extern int cmd_tar_tree(int argc, const char **argv, const char *prefix);
> diff --git a/builtin/checkout.c b/builtin/checkout.c
> index 764e1a83a1..7dc0f4d3f3 100644
> --- a/builtin/checkout.c
> +++ b/builtin/checkout.c
> @@ -33,6 +33,16 @@ static const char * const checkout_usage[] = {
>         NULL,
>  };
>
> +static const char * const switch_branch_usage[] = {
> +       N_("git switch-branch [<options>] [<branch>]"),
> +       NULL,
> +};
> +
> +static const char * const restore_files_usage[] = {
> +       N_("git restore-files [<options>] [<branch>] -- <file>..."),
> +       NULL,
> +};
> +
>  struct checkout_opts {
>         int patch_mode;
>         int quiet;
> @@ -1302,31 +1312,23 @@ static struct option *add_checkout_path_options(struct checkout_opts *opts,
>         return newopts;
>  }
>
> -int cmd_checkout(int argc, const char **argv, const char *prefix)
> +static int checkout_main(int argc, const char **argv, const char *prefix,
> +                        struct checkout_opts *opts, struct option *options,
> +                        const char * const usagestr[])
>  {
> -       struct checkout_opts real_opts;
> -       struct checkout_opts *opts = &real_opts;
>         struct branch_info new_branch_info;
>         int dwim_remotes_matched = 0;
> -       struct option *options = NULL;
>
> -       memset(opts, 0, sizeof(*opts));
>         memset(&new_branch_info, 0, sizeof(new_branch_info));
>         opts->overwrite_ignore = 1;
>         opts->prefix = prefix;
>         opts->show_progress = -1;
> -       opts->dwim_new_local_branch = 1;
>
>         git_config(git_checkout_config, opts);
>
>         opts->track = BRANCH_TRACK_UNSPECIFIED;
>
> -       options = parse_options_dup(options);
> -       options = add_common_options(opts, options);
> -       options = add_switch_branch_options(opts, options);
> -       options = add_checkout_path_options(opts, options);
> -
> -       argc = parse_options(argc, argv, prefix, options, checkout_usage,
> +       argc = parse_options(argc, argv, prefix, options, usagestr,
>                              PARSE_OPT_KEEP_DASHDASH);
>
>         if (opts->show_progress < 0) {
> @@ -1455,3 +1457,61 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
>                 return checkout_branch(opts, &new_branch_info);
>         }
>  }
> +
> +int cmd_checkout(int argc, const char **argv, const char *prefix)
> +{
> +       struct checkout_opts opts;
> +       struct option *options = NULL;
> +       int ret;
> +
> +       memset(&opts, 0, sizeof(opts));
> +       opts.dwim_new_local_branch = 1;
> +
> +       options = parse_options_dup(options);
> +       options = add_common_options(&opts, options);
> +       options = add_switch_branch_options(&opts, options);
> +       options = add_checkout_path_options(&opts, options);
> +
> +       ret = checkout_main(argc, argv, prefix, &opts,
> +                           options, checkout_usage);
> +       FREE_AND_NULL(options);
> +       return ret;
> +}
> +
> +int cmd_switch_branch(int argc, const char **argv, const char *prefix)
> +{
> +       struct checkout_opts opts;
> +       struct option *options = NULL;
> +       int ret;
> +
> +       memset(&opts, 0, sizeof(opts));
> +       opts.dwim_new_local_branch = 1;
> +
> +       options = parse_options_dup(options);
> +       options = add_common_options(&opts, options);
> +       options = add_switch_branch_options(&opts, options);
> +
> +       ret = checkout_main(argc, argv, prefix, &opts,
> +                           options, switch_branch_usage);
> +       FREE_AND_NULL(options);
> +       return ret;
> +}
> +
> +int cmd_restore_files(int argc, const char **argv, const char *prefix)
> +{
> +       struct checkout_opts opts;
> +       struct option *options = NULL;
> +       int ret;
> +
> +       memset(&opts, 0, sizeof(opts));
> +       opts.dwim_new_local_branch = 1;
> +
> +       options = parse_options_dup(options);
> +       options = add_common_options(&opts, options);
> +       options = add_checkout_path_options(&opts, options);
> +
> +       ret = checkout_main(argc, argv, prefix, &opts,
> +                           options, restore_files_usage);
> +       FREE_AND_NULL(options);
> +       return ret;
> +}
> diff --git a/command-list.txt b/command-list.txt
> index 3a9af104b5..4638802754 100644
> --- a/command-list.txt
> +++ b/command-list.txt
> @@ -151,6 +151,7 @@ git-replace                             ancillarymanipulators           complete
>  git-request-pull                        foreignscminterface             complete
>  git-rerere                              ancillaryinterrogators
>  git-reset                               mainporcelain           worktree
> +git-restore-files                       mainporcelain           worktree
>  git-revert                              mainporcelain
>  git-rev-list                            plumbinginterrogators
>  git-rev-parse                           plumbinginterrogators
> @@ -171,6 +172,7 @@ git-status                              mainporcelain           info
>  git-stripspace                          purehelpers
>  git-submodule                           mainporcelain
>  git-svn                                 foreignscminterface
> +git-switch-branch                       mainporcelain           history
>  git-symbolic-ref                        plumbingmanipulators
>  git-tag                                 mainporcelain           history
>  git-unpack-file                         plumbinginterrogators
> diff --git a/git.c b/git.c
> index 2f604a41ea..a2be6c3eb5 100644
> --- a/git.c
> +++ b/git.c
> @@ -542,6 +542,7 @@ static struct cmd_struct commands[] = {
>         { "replace", cmd_replace, RUN_SETUP },
>         { "rerere", cmd_rerere, RUN_SETUP },
>         { "reset", cmd_reset, RUN_SETUP },
> +       { "restore-files", cmd_restore_files, RUN_SETUP | NEED_WORK_TREE },
>         { "rev-list", cmd_rev_list, RUN_SETUP | NO_PARSEOPT },
>         { "rev-parse", cmd_rev_parse, NO_PARSEOPT },
>         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
> @@ -557,6 +558,7 @@ static struct cmd_struct commands[] = {
>         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
>         { "stripspace", cmd_stripspace },
>         { "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT },
> +       { "switch-branch", cmd_switch_branch, RUN_SETUP | NEED_WORK_TREE },
>         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
>         { "tag", cmd_tag, RUN_SETUP | DELAY_PAGER_CONFIG },
>         { "unpack-file", cmd_unpack_file, RUN_SETUP | NO_PARSEOPT },
> --
> 2.20.0.rc1.380.g3eb999425c.dirty
>

>> +Updates files in the working tree to match the version in the index
>> +or the specified tree.
>> +
>> +'git restore-files' [--from=<tree-ish>] <pathspec>...::
>
> <tree-ish> and <pathspec>?  I understand <commit-ish> and <pathspec>,
> or <tree-ish> but have no clue why it'd be okay to specify <tree-ish>
> and <pathspec> together.  What does that even mean?

>> +       Overwrite paths in the working tree by replacing with the
>> +       contents in the index or in the <tree-ish> (most often a
>> +       commit).  When a <tree-ish> is given, the paths that
>> +       match the <pathspec> are updated both in the index and in
>> +       the working tree.
>
> Is that the default we really want for this command?  Why do we
> automatically assume these files are ready for commit?  I understand
> that it's what checkout did, but I'd find it more natural to only
> affect the working tree by default.  We can give it an option for
> affecting the index instead (or perhaps in addition).

> > +'git restore-files' [--from=<tree-ish>] <pathspec>...
>
> Isn't this already inferred by the previous line?  Or was the
> inclusion of --from on the previous line in error?  Looking at the
> git-checkout manpage, it looks like you may have just been copying an
> existing weirdness, but it needs to be fixed.  ;-)

> > +'git restore-files' (-p|--patch) [--from=<tree-ish>] [<pathspec>...]
> > +
> > +DESCRIPTION
> > +-----------
> > +Updates files in the working tree to match the version in the index
> > +or the specified tree.
> > +
> > +'git restore-files' [--from=<tree-ish>] <pathspec>...::
>
> <tree-ish> and <pathspec>?  I understand <commit-ish> and <pathspec>,
> or <tree-ish> but have no clue why it'd be okay to specify <tree-ish>
> and <pathspec> together.  What does that even mean?
>
> Also, rather than fixing from <tree-ish> to <commit-ish> or <commit>,
> perhaps we should just use <revision> here?  (I'm thinking of git
> rev-parse's "Specifying revisions", which suggests "revisions" as a
> good substitute for "commit-ish" that isn't quite so weird for new
> users.)

> > +       Overwrite paths in the working tree by replacing with the
> > +       contents in the index or in the <tree-ish> (most often a
> > +       commit).  When a <tree-ish> is given, the paths that
> > +       match the <pathspec> are updated both in the index and in
> > +       the working tree.
>
> Is that the default we really want for this command?  Why do we
> automatically assume these files are ready for commit?  I understand
> that it's what checkout did, but I'd find it more natural to only
> affect the working tree by default.  We can give it an option for
> affecting the index instead (or perhaps in addition).

> > +--ours::
> > +--theirs::
> > +       Check out stage #2 ('ours') or #3 ('theirs') for unmerged
> > +       paths.
> > ++
> > +Note that during `git rebase` and `git pull --rebase`, 'ours' and
> > +'theirs' may appear swapped; `--ours` gives the version from the
> > +branch the changes are rebased onto, while `--theirs` gives the
> > +version from the branch that holds your work that is being rebased.
> > ++
> > +This is because `rebase` is used in a workflow that treats the
> > +history at the remote as the shared canonical one, and treats the
> > +work done on the branch you are rebasing as the third-party work to
> > +be integrated, and you are temporarily assuming the role of the
> > +keeper of the canonical history during the rebase.  As the keeper of
> > +the canonical history, you need to view the history from the remote
> > +as `ours` (i.e. "our shared canonical history"), while what you did
> > +on your side branch as `theirs` (i.e. "one contributor's work on top
> > +of it").
>
> Total aside because I'm not sure what you could change here, but man
> do I hate this.

> > +Part of the linkgit:git[1] suite
>
>
> My single biggest worry about this whole series is that I'm worried
> you're perpetuating and even further ingraining one of the biggest
> usability problems with checkout: people suggest and use it for
> reverting/restoring paths to a previous version, but it doesn't do
> that:
>
> git restore-files --from master~10 Documentation/
> <edit some non-documentation files>
> git add -u
> git commit -m "Rationale for changing files including reverting Documentation/"
>
> In particular, now you have a mixture of files in Documentation/ from
> master~10 (er, now likely master~11) and HEAD~1; any files and
> sub-directories that existed in HEAD~1 still remain and are mixed with
> all other files in Documentation/ from the older commit.
>
> You may think this is a special case, but this particular issue
> results in some pretty bad surprises.  Also, it was pretty surprising
> to me just how difficult it was to implement an svn-like revert in
> EasyGit, in large part because of this 'oversight' in git.  git
> checkout -- <paths> to me has always been fundamentally wrong, but I
> just wasn't sure if I wanted to fight the backward compatibility
> battle and suggest changing it.  With a new command, we definitely
> shouldn't be reinforcing this error.  (And maybe we should consider
> taking the time to fix git checkout too.)

> > +If the branch exists in multiple remotes and one of them is named by
> > +the `checkout.defaultRemote` configuration variable, we'll use that
> > +one for the purposes of disambiguation, even if the `<branch>` isn't
> > +unique across all remotes. Set it to
> > +e.g. `checkout.defaultRemote=origin` to always checkout remote
> > +branches from there if `<branch>` is ambiguous but exists on the
> > +'origin' remote. See also `checkout.defaultRemote` in
> > +linkgit:git-config[1].
>
> So switch-branch will be controlled by checkout.* config variables?
> That probably makes the most sense, but it does dilute the advantage
> of adding these simpler commands.
>
> Also, the fact that we're trying to make a simpler command makes me
> think that removing the auto-vivify behavior from the default and
> adding a simple flag which users can pass to request will allow this
> part of the documentation to be hidden behind the appropriate flag,
> which may make it easier for users to compartmentalize the command and
> it's options, enabling them to learn as they go.

> > +'git switch-branch' -c|-C <new_branch> [<start_point>]::
> > +
> > +       Specifying `-c` causes a new branch to be created as if
> > +       linkgit:git-branch[1] were called and then switched to. In
> > +       this case you can use the `--track` or `--no-track` options,
> > +       which will be passed to 'git branch'.  As a convenience,
> > +       `--track` without `-c` implies branch creation; see the
> > +       description of `--track` below.
>
> Can we get rid of --track/--no-track and just provide a flag (which
> takes no arguments) for the user to use?  Problems with --track:
>   * it's not even in your synopsis
>   * user has to repeat themselves (e.g. 'next' in two places from '-c
> next --track origin/next'); this repetition is BOTH laborious AND
> error-prone
>   * it's rather inconsistent: --track is the default due to
> auto-vivify when the user specifies nothing but a branch name that
> doesn't exist yet, but when the user realizes the branch doesn't exist
> yet and asks to have it created then suddenly tracking is not the
> default??

> I'm not sure what's best, but here's some food for thought:
>
>
>    git switch-branch <branch>
> switches to <branch>, if it exists.  Error cases:
>   * If <branch> isn't actually a branch but a <tag> or
> <remote-tracking-branch> or <revision>, error out and suggest using
> --detach.
>   * If <branch> isn't actually a branch but there is a similarly named
> <remote-tracking-branch> (e.g. origin/<branch>), then suggest using
> -c.

> > +If `-C` is given, <new_branch> is created if it doesn't exist;
> > +otherwise, it is reset. This is the transactional equivalent of
> > ++
> > +------------
> > +$ git branch -f <branch> [<start_point>]
> > +$ git switch-branch <branch>
> > +------------
> > ++
> > +that is to say, the branch is not reset/created unless "git
> > +switch-branch" is successful.
>
> ...and when exactly would it fail?  Reading this, it looks like the
> only possible error condition was removed due saying we'll reset the
> branch if it already exists, so it's rather confusing.

> > +'git switch-branch' --detach [<commit>]::
> > +
> > +       Prepare to work on a unnamed branch on top of <commit> (see
> > +       "DETACHED HEAD" section), and updating the index and the files
> > +       in the working tree.  Local modifications to the files in the
> > +       working tree are kept, so that the resulting working tree will
> > +       be the state recorded in the commit plus the local
> > +       modifications.
> > ++
> > +When the <commit> argument is a branch name, the `--detach` option can
> > +be used to detach HEAD at the tip of the branch (`git switch-branch
> > +<branch>` would check out that branch without detaching HEAD).
> > ++
> > +Omitting <commit> detaches HEAD at the tip of the current branch.
> > +
> > +OPTIONS
> > +-------
> > +-q::
> > +--quiet::
> > +       Quiet, suppress feedback messages.
> > +
> > +--[no-]progress::
> > +       Progress status is reported on the standard error stream
> > +       by default when it is attached to a terminal, unless `--quiet`
> > +       is specified. This flag enables progress reporting even if not
> > +       attached to a terminal, regardless of `--quiet`.
> > +
> > +-f::
> > +--force::
> > +       Proceed even if the index or the working tree differs from
> > +       HEAD.  This is used to throw away local changes.
>
> Haven't thought through this thoroughly, but do we really need an
> option for that instead of telling users to 'git reset --hard HEAD'
> before switching branches if they want their stuff thrown away?

> > +-c <new_branch>::
> > +--create <new_branch>::
> > +       Create a new branch named <new_branch> and start it at
> > +       <start_point>; see linkgit:git-branch[1] for details.
> > +
> > +-C <new_branch>::
> > +--force-create <new_branch>::
> > +       Creates the branch <new_branch> and start it at <start_point>;
> > +       if it already exists, then reset it to <start_point>. This is
> > +       equivalent to running "git branch" with "-f"; see
> > +       linkgit:git-branch[1] for details.
>
> Makes sense, but let's get the -b/-B vs. -c/-C consistent.

> > +-l::
> > +       Create the new branch's reflog; see linkgit:git-branch[1] for
> > +       details.
>
> ??  Jettison this.

> > +--orphan <new_branch>::
> > +       Create a new 'orphan' branch, named <new_branch>, started from
> > +       <start_point> and switch to it.  The first commit made on this
>
> What??  started from <start_point>?  The whole point of --orphan is
> you have no parent, i.e. no start point.  Also, why does the
> explanation reference an argument that wasn't in the immediately
> preceding synopsis?

> > +       new branch will have no parents and it will be the root of a new
> > +       history totally disconnected from all the other branches and
> > +       commits.
> > ++
> > +The index and the working tree are adjusted as if you had previously run
> > +"git checkout <start_point>".  This allows you to start a new history
> > +that records a set of paths similar to <start_point> by easily running
> > +"git commit -a" to make the root commit.
> > ++
> > +This can be useful when you want to publish the tree from a commit
> > +without exposing its full history. You might want to do this to publish
> > +an open source branch of a project whose current tree is "clean", but
> > +whose full history contains proprietary or otherwise encumbered bits of
> > +code.
> > ++
> > +If you want to start a disconnected history that records a set of paths
> > +that is totally different from the one of <start_point>, then you should
> > +clear the index and the working tree right after creating the orphan
> > +branch by running "git rm -rf ." from the top level of the working tree.
> > +Afterwards you will be ready to prepare your new files, repopulating the
> > +working tree, by copying them from elsewhere, extracting a tarball, etc.
>
> Ick.  Seems overly complex.  I'd rather that --orphan defaulted to
> clearing the index and working tree, and that one would need to pass
> HEAD for <start_point> if you wanted to start out with all those other
> files.  That would certainly make the explanation a little clearer to
> users, and more natural when they start experimenting with it.
>
> However, --orphan is pretty special case.  Do we perhaps want to leave
> it out of this new command and only include it in checkout?

> > +-m::
> > +--merge::
> > +       If you have local modifications to one or more files that are
> > +       different between the current branch and the branch to which
> > +       you are switching, the command refuses to switch branches in
> > +       order to preserve your modifications in context.  However,
> > +       with this option, a three-way merge between the current
> > +       branch, your working tree contents, and the new branch is
> > +       done, and you will be on the new branch.
> > ++
> > +When a merge conflict happens, the index entries for conflicting
> > +paths are left unmerged, and you need to resolve the conflicts
> > +and mark the resolved paths with `git add` (or `git rm` if the merge
> > +should result in deletion of the path).
> > +
> > +--conflict=<style>::
> > +       The same as --merge option above, but changes the way the
> > +       conflicting hunks are presented, overriding the
> > +       merge.conflictStyle configuration variable.  Possible values are
> > +       "merge" (default) and "diff3" (in addition to what is shown by
> > +       "merge" style, shows the original contents).
> > +
> > +--ignore-other-worktrees::
> > +       `git switch-branch` refuses when the wanted ref is already
> > +       checked out by another worktree. This option makes it check
> > +       the ref out anyway. In other words, the ref can be held by
> > +       more than one worktree.
>
> seems rather dangerous...is the goal to be an easier-to-use suggestion
> for new users while checkout continues to exist, or is this command
> meant to handle all branch switching functionality that checkout has?

> > +<branch>::
> > +       Branch to checkout; if it refers to a branch (i.e., a name that,
> > +       when prepended with "refs/heads/", is a valid ref), then that
> > +       branch is checked out. Otherwise, if it refers to a valid
> > +       commit, your HEAD becomes "detached" and you are no longer on
> > +       any branch (see below for details).
>
> I thought we requiring --detach in order to detach.  Does this
> paragraph need updating?  Also, if we require --detach when we'll be
> detaching HEAD, then this paragraph gets a LOT simpler.

> > +You can use the `"@{-N}"` syntax to refer to the N-th last
> > +branch/commit checked out using "git checkout" operation. You may
> > +also specify `-` which is synonymous to `"@{-1}`.
> > ++
> > +As a special case, you may use `"A...B"` as a shortcut for the
> > +merge base of `A` and `B` if there is exactly one merge base. You can
> > +leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
>
> I actually didn't know about the A...B special case for checkout.
> Interesting...but I'm starting to wonder if this is too much info for
> a "simplified command".

>
> Thanks for all the comments! There are still some I haven't replied
> (either I'll agree and do it anyway, or I'll need some more time to
> digest)
>
> On Tue, Dec 4, 2018 at 1:45 AM Elijah Newren <newren@gmail.com> wrote:
> > > +'git restore-files' [--from=<tree-ish>] <pathspec>...
> >
> > Isn't this already inferred by the previous line?  Or was the
> > inclusion of --from on the previous line in error?  Looking at the
> > git-checkout manpage, it looks like you may have just been copying an
> > existing weirdness, but it needs to be fixed.  ;-)
>
> Hehe.
>
> > > +'git restore-files' (-p|--patch) [--from=<tree-ish>] [<pathspec>...]
> > > +
> > > +DESCRIPTION
> > > +-----------
> > > +Updates files in the working tree to match the version in the index
> > > +or the specified tree.
> > > +
> > > +'git restore-files' [--from=<tree-ish>] <pathspec>...::
> >
> > <tree-ish> and <pathspec>?  I understand <commit-ish> and <pathspec>,
> > or <tree-ish> but have no clue why it'd be okay to specify <tree-ish>
> > and <pathspec> together.  What does that even mean?
> >
> > Also, rather than fixing from <tree-ish> to <commit-ish> or <commit>,
> > perhaps we should just use <revision> here?  (I'm thinking of git
> > rev-parse's "Specifying revisions", which suggests "revisions" as a
> > good substitute for "commit-ish" that isn't quite so weird for new
> > users.)
>
> tree-ish is technically more accurate. But I'm ok with just
> <revision>. If you give it a blob oid then you should get a nice
> explanation what you're doing wrong anyway.

> > > +       Overwrite paths in the working tree by replacing with the
> > > +       contents in the index or in the <tree-ish> (most often a
> > > +       commit).  When a <tree-ish> is given, the paths that
> > > +       match the <pathspec> are updated both in the index and in
> > > +       the working tree.
> >
> > Is that the default we really want for this command?  Why do we
> > automatically assume these files are ready for commit?  I understand
> > that it's what checkout did, but I'd find it more natural to only
> > affect the working tree by default.  We can give it an option for
> > affecting the index instead (or perhaps in addition).
>
> Yeah, that behavior of updating the index always bothers me when I use
> it but I seemed to forget when working on this.
>
> > > +--ours::
> > > +--theirs::
> > > +       Check out stage #2 ('ours') or #3 ('theirs') for unmerged
> > > +       paths.
> > > ++
> > > +Note that during `git rebase` and `git pull --rebase`, 'ours' and
> > > +'theirs' may appear swapped; `--ours` gives the version from the
> > > +branch the changes are rebased onto, while `--theirs` gives the
> > > +version from the branch that holds your work that is being rebased.
> > > ++
> > > +This is because `rebase` is used in a workflow that treats the
> > > +history at the remote as the shared canonical one, and treats the
> > > +work done on the branch you are rebasing as the third-party work to
> > > +be integrated, and you are temporarily assuming the role of the
> > > +keeper of the canonical history during the rebase.  As the keeper of
> > > +the canonical history, you need to view the history from the remote
> > > +as `ours` (i.e. "our shared canonical history"), while what you did
> > > +on your side branch as `theirs` (i.e. "one contributor's work on top
> > > +of it").
> >
> > Total aside because I'm not sure what you could change here, but man
> > do I hate this.
>
> Uh it's actually documented? I'm always confused by this too. --ours
> and --theirs at this point are pretty much tied to stage 2 and 3.
> Nothing I can do about it. But if you could come up with some other
> option names, then we could make "new ours" to be stage 3 during
> rebase, for example.

> > > +Part of the linkgit:git[1] suite
> >
> >
> > My single biggest worry about this whole series is that I'm worried
> > you're perpetuating and even further ingraining one of the biggest
> > usability problems with checkout: people suggest and use it for
> > reverting/restoring paths to a previous version, but it doesn't do
> > that:
> >
> > git restore-files --from master~10 Documentation/
> > <edit some non-documentation files>
> > git add -u
> > git commit -m "Rationale for changing files including reverting Documentation/"
> >
> > In particular, now you have a mixture of files in Documentation/ from
> > master~10 (er, now likely master~11) and HEAD~1; any files and
> > sub-directories that existed in HEAD~1 still remain and are mixed with
> > all other files in Documentation/ from the older commit.
> >
> > You may think this is a special case, but this particular issue
> > results in some pretty bad surprises.  Also, it was pretty surprising
> > to me just how difficult it was to implement an svn-like revert in
> > EasyGit, in large part because of this 'oversight' in git.  git
> > checkout -- <paths> to me has always been fundamentally wrong, but I
> > just wasn't sure if I wanted to fight the backward compatibility
> > battle and suggest changing it.  With a new command, we definitely
> > shouldn't be reinforcing this error.  (And maybe we should consider
> > taking the time to fix git checkout too.)
>
> What would be the right behavior for
>
>  git restore-files --from=master~10 Documentation/
>
> then? Consider it an error? I often use "git checkout HEAD" and "git
> checkout HEAD^" (usually with -p) but not very far back like
> master~10.

> > > +If the branch exists in multiple remotes and one of them is named by
> > > +the `checkout.defaultRemote` configuration variable, we'll use that
> > > +one for the purposes of disambiguation, even if the `<branch>` isn't
> > > +unique across all remotes. Set it to
> > > +e.g. `checkout.defaultRemote=origin` to always checkout remote
> > > +branches from there if `<branch>` is ambiguous but exists on the
> > > +'origin' remote. See also `checkout.defaultRemote` in
> > > +linkgit:git-config[1].
> >
> > So switch-branch will be controlled by checkout.* config variables?
> > That probably makes the most sense, but it does dilute the advantage
> > of adding these simpler commands.
> >
> > Also, the fact that we're trying to make a simpler command makes me
> > think that removing the auto-vivify behavior from the default and
> > adding a simple flag which users can pass to request will allow this
> > part of the documentation to be hidden behind the appropriate flag,
> > which may make it easier for users to compartmentalize the command and
> > it's options, enabling them to learn as they go.
>
> Sounds good. I don't know a good name for this new option though so
> unless anybody comes up with some suggestion, I'll just disable
> checkout.defaultRemote in switch-branch. If it comes back as a new
> option, it can always be added later.
>
> > > +'git switch-branch' -c|-C <new_branch> [<start_point>]::
> > > +
> > > +       Specifying `-c` causes a new branch to be created as if
> > > +       linkgit:git-branch[1] were called and then switched to. In
> > > +       this case you can use the `--track` or `--no-track` options,
> > > +       which will be passed to 'git branch'.  As a convenience,
> > > +       `--track` without `-c` implies branch creation; see the
> > > +       description of `--track` below.
> >
> > Can we get rid of --track/--no-track and just provide a flag (which
> > takes no arguments) for the user to use?  Problems with --track:
> >   * it's not even in your synopsis
> >   * user has to repeat themselves (e.g. 'next' in two places from '-c
> > next --track origin/next'); this repetition is BOTH laborious AND
> > error-prone
> >   * it's rather inconsistent: --track is the default due to
> > auto-vivify when the user specifies nothing but a branch name that
> > doesn't exist yet, but when the user realizes the branch doesn't exist
> > yet and asks to have it created then suddenly tracking is not the
> > default??
>
> I don't think --track is default anymore (maybe I haven't updated the
> man page correctly). The dwim behavior is only activated in
> switch-branch when you specify --guess to reduce the amount of magic
> we throw at the user. With that in mind, do we still hide
> --track/--no-track from switch-branch?

> > I'm not sure what's best, but here's some food for thought:
> >
> >
> >    git switch-branch <branch>
> > switches to <branch>, if it exists.  Error cases:
> >   * If <branch> isn't actually a branch but a <tag> or
> > <remote-tracking-branch> or <revision>, error out and suggest using
> > --detach.
> >   * If <branch> isn't actually a branch but there is a similarly named
> > <remote-tracking-branch> (e.g. origin/<branch>), then suggest using
> > -c.
>
> I would make these advice so I can hide them. Or if I manage to make
> all these hints one line then I'll make it unconditional.
>
> >   git switch-branch -c <branch>
> > creates <branch> and, if a relevant-remote-tracking branch exists,
> > base the branch on that revision and set the new branch up to track
>
> Hmm.. this is a bit magical and could be surprising. If I create (and
> switch to) a new branch foo, I don't necessarily mean tracking
> origin/foo (I may not even think about origin/foo when I type the
> command). So tentatively no.

>
> > > +If `-C` is given, <new_branch> is created if it doesn't exist;
> > > +otherwise, it is reset. This is the transactional equivalent of
> > > ++
> > > +------------
> > > +$ git branch -f <branch> [<start_point>]
> > > +$ git switch-branch <branch>
> > > +------------
> > > ++
> > > +that is to say, the branch is not reset/created unless "git
> > > +switch-branch" is successful.
> >
> > ...and when exactly would it fail?  Reading this, it looks like the
> > only possible error condition was removed due saying we'll reset the
> > branch if it already exists, so it's rather confusing.
>
> Yeah probably just scrape it. The atomic nature is not worth highlighting.
>
>
> > > +'git switch-branch' --detach [<commit>]::
> > > +
> > > +       Prepare to work on a unnamed branch on top of <commit> (see
> > > +       "DETACHED HEAD" section), and updating the index and the files
> > > +       in the working tree.  Local modifications to the files in the
> > > +       working tree are kept, so that the resulting working tree will
> > > +       be the state recorded in the commit plus the local
> > > +       modifications.
> > > ++
> > > +When the <commit> argument is a branch name, the `--detach` option can
> > > +be used to detach HEAD at the tip of the branch (`git switch-branch
> > > +<branch>` would check out that branch without detaching HEAD).
> > > ++
> > > +Omitting <commit> detaches HEAD at the tip of the current branch.
> > > +
> > > +OPTIONS
> > > +-------
> > > +-q::
> > > +--quiet::
> > > +       Quiet, suppress feedback messages.
> > > +
> > > +--[no-]progress::
> > > +       Progress status is reported on the standard error stream
> > > +       by default when it is attached to a terminal, unless `--quiet`
> > > +       is specified. This flag enables progress reporting even if not
> > > +       attached to a terminal, regardless of `--quiet`.
> > > +
> > > +-f::
> > > +--force::
> > > +       Proceed even if the index or the working tree differs from
> > > +       HEAD.  This is used to throw away local changes.
> >
> > Haven't thought through this thoroughly, but do we really need an
> > option for that instead of telling users to 'git reset --hard HEAD'
> > before switching branches if they want their stuff thrown away?
>
> For me it's just a bit more convenient. Hit an error when switching
> branch? Recall the command from bash history, stick -f in it and run.
> Elsewhere I think both Junio and Thomas (or maybe only Junio) suggests
> moving the "git reset" functionality without moving HEAD to one of
> these commands, which goes the opposite direction...

> > > +-c <new_branch>::
> > > +--create <new_branch>::
> > > +       Create a new branch named <new_branch> and start it at
> > > +       <start_point>; see linkgit:git-branch[1] for details.
> > > +
> > > +-C <new_branch>::
> > > +--force-create <new_branch>::
> > > +       Creates the branch <new_branch> and start it at <start_point>;
> > > +       if it already exists, then reset it to <start_point>. This is
> > > +       equivalent to running "git branch" with "-f"; see
> > > +       linkgit:git-branch[1] for details.
> >
> > Makes sense, but let's get the -b/-B vs. -c/-C consistent.
>
> Another option I'm considering is -n/-N (for _new_ branch). Maybe
> -c/-C is good enough.

> > > +-l::
> > > +       Create the new branch's reflog; see linkgit:git-branch[1] for
> > > +       details.
> >
> > ??  Jettison this.
>
> Yep. It looks weird to me too. reflog is just behind the scene these
> days. Nobody need to explicitly ask for reflog anymore.
>
> > > +--orphan <new_branch>::
> > > +       Create a new 'orphan' branch, named <new_branch>, started from
> > > +       <start_point> and switch to it.  The first commit made on this
> >
> > What??  started from <start_point>?  The whole point of --orphan is
> > you have no parent, i.e. no start point.  Also, why does the
> > explanation reference an argument that wasn't in the immediately
> > preceding synopsis?
>
> I guess bad phrasing. It should be "switch to <start_point> first,
> then prepare the worktree so that the first commit will have no
> parent". Or something along that line.
>
> You should really review git-checkout.txt btw ;-)

> > > +       new branch will have no parents and it will be the root of a new
> > > +       history totally disconnected from all the other branches and
> > > +       commits.
> > > ++
> > > +The index and the working tree are adjusted as if you had previously run
> > > +"git checkout <start_point>".  This allows you to start a new history
> > > +that records a set of paths similar to <start_point> by easily running
> > > +"git commit -a" to make the root commit.
> > > ++
> > > +This can be useful when you want to publish the tree from a commit
> > > +without exposing its full history. You might want to do this to publish
> > > +an open source branch of a project whose current tree is "clean", but
> > > +whose full history contains proprietary or otherwise encumbered bits of
> > > +code.
> > > ++
> > > +If you want to start a disconnected history that records a set of paths
> > > +that is totally different from the one of <start_point>, then you should
> > > +clear the index and the working tree right after creating the orphan
> > > +branch by running "git rm -rf ." from the top level of the working tree.
> > > +Afterwards you will be ready to prepare your new files, repopulating the
> > > +working tree, by copying them from elsewhere, extracting a tarball, etc.
> >
> > Ick.  Seems overly complex.  I'd rather that --orphan defaulted to
> > clearing the index and working tree, and that one would need to pass
> > HEAD for <start_point> if you wanted to start out with all those other
> > files.  That would certainly make the explanation a little clearer to
> > users, and more natural when they start experimenting with it.
> >
> > However, --orphan is pretty special case.  Do we perhaps want to leave
> > it out of this new command and only include it in checkout?
>
> I started this by simply splitting git-checkout in two commands that,
> combined, can do everything git-checkout can. Then suggestions to have
> better default came in and I think we started to drift further to
> _removing_ options and falling back to git-checkout.
>
> I think we could still keep "complicated" options as long as they are
> clearly described and don't surprise users until they figure them out.
> That way I don't have to go back to git-checkout and deal with all the
> ambiguation it creates.

> > > +-m::
> > > +--merge::
> > > +       If you have local modifications to one or more files that are
> > > +       different between the current branch and the branch to which
> > > +       you are switching, the command refuses to switch branches in
> > > +       order to preserve your modifications in context.  However,
> > > +       with this option, a three-way merge between the current
> > > +       branch, your working tree contents, and the new branch is
> > > +       done, and you will be on the new branch.
> > > ++
> > > +When a merge conflict happens, the index entries for conflicting
> > > +paths are left unmerged, and you need to resolve the conflicts
> > > +and mark the resolved paths with `git add` (or `git rm` if the merge
> > > +should result in deletion of the path).
> > > +
> > > +--conflict=<style>::
> > > +       The same as --merge option above, but changes the way the
> > > +       conflicting hunks are presented, overriding the
> > > +       merge.conflictStyle configuration variable.  Possible values are
> > > +       "merge" (default) and "diff3" (in addition to what is shown by
> > > +       "merge" style, shows the original contents).
> > > +
> > > +--ignore-other-worktrees::
> > > +       `git switch-branch` refuses when the wanted ref is already
> > > +       checked out by another worktree. This option makes it check
> > > +       the ref out anyway. In other words, the ref can be held by
> > > +       more than one worktree.
> >
> > seems rather dangerous...is the goal to be an easier-to-use suggestion
> > for new users while checkout continues to exist, or is this command
> > meant to handle all branch switching functionality that checkout has?
>
> As explained above. I'm still thinking the latter, but with fewer
> surprises and confusion. Though I guess I could be convinced to go
> with the former (the problem with the former is, even as a
> no-longer-new user, I still find git-checkout not that pleasant to use
> and want a better replacement)
>
> > > +<branch>::
> > > +       Branch to checkout; if it refers to a branch (i.e., a name that,
> > > +       when prepended with "refs/heads/", is a valid ref), then that
> > > +       branch is checked out. Otherwise, if it refers to a valid
> > > +       commit, your HEAD becomes "detached" and you are no longer on
> > > +       any branch (see below for details).
> >
> > I thought we requiring --detach in order to detach.  Does this
> > paragraph need updating?  Also, if we require --detach when we'll be
> > detaching HEAD, then this paragraph gets a LOT simpler.
>
> Yep. I really need to read through the document and update all of it.
>
> > > +You can use the `"@{-N}"` syntax to refer to the N-th last
> > > +branch/commit checked out using "git checkout" operation. You may
> > > +also specify `-` which is synonymous to `"@{-1}`.
> > > ++
> > > +As a special case, you may use `"A...B"` as a shortcut for the
> > > +merge base of `A` and `B` if there is exactly one merge base. You can
> > > +leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
> >
> > I actually didn't know about the A...B special case for checkout.
> > Interesting...but I'm starting to wonder if this is too much info for
> > a "simplified command".
>
> I could just hint about A...B and send the user to git-checkout.txt if
> they need to know more. They can learn about git-checkout that way
> too.

> > > > +--ours::
> > > > +--theirs::
> > > > +       Check out stage #2 ('ours') or #3 ('theirs') for unmerged
> > > > +       paths.
> > > > ++
> > > > +Note that during `git rebase` and `git pull --rebase`, 'ours' and
> > > > +'theirs' may appear swapped; `--ours` gives the version from the
> > > > +branch the changes are rebased onto, while `--theirs` gives the
> > > > +version from the branch that holds your work that is being rebased.
> > > > ++
> > > > +This is because `rebase` is used in a workflow that treats the
> > > > +history at the remote as the shared canonical one, and treats the
> > > > +work done on the branch you are rebasing as the third-party work to
> > > > +be integrated, and you are temporarily assuming the role of the
> > > > +keeper of the canonical history during the rebase.  As the keeper of
> > > > +the canonical history, you need to view the history from the remote
> > > > +as `ours` (i.e. "our shared canonical history"), while what you did
> > > > +on your side branch as `theirs` (i.e. "one contributor's work on top
> > > > +of it").
> > >
> > > Total aside because I'm not sure what you could change here, but man
> > > do I hate this.
> >
> > Uh it's actually documented? I'm always confused by this too. --ours
> > and --theirs at this point are pretty much tied to stage 2 and 3.
> > Nothing I can do about it. But if you could come up with some other
> > option names, then we could make "new ours" to be stage 3 during
> > rebase, for example.
>
> I don't think it's a naming issue, personally.  Years ago we could
> have defined --ours and --theirs differently based on which kind of
> operation we were in the middle of, but you are probably right that
> they are now tied to stage 2 and 3.  But there's another place that we
> might still be able to address this; I think the brain-damage here may
> have just been due to the fact that the recursive merge machinery was
> rather inflexible and required HEAD to be stage 2.  If it were a
> little more flexible, then we might just be able to make this problem
> go away.  Maybe it can still be fixed (I haven't dug too deeply into
> it), but if so, the only fix needed here would be to remove this long
> explanation about why the tool gets things totally backward.

> > > > +'git switch-branch' -c|-C <new_branch> [<start_point>]::
> > > > +
> > > > +       Specifying `-c` causes a new branch to be created as if
> > > > +       linkgit:git-branch[1] were called and then switched to. In
> > > > +       this case you can use the `--track` or `--no-track` options,
> > > > +       which will be passed to 'git branch'.  As a convenience,
> > > > +       `--track` without `-c` implies branch creation; see the
> > > > +       description of `--track` below.
> > >
> > > Can we get rid of --track/--no-track and just provide a flag (which
> > > takes no arguments) for the user to use?  Problems with --track:
> > >   * it's not even in your synopsis
> > >   * user has to repeat themselves (e.g. 'next' in two places from '-c
> > > next --track origin/next'); this repetition is BOTH laborious AND
> > > error-prone
> > >   * it's rather inconsistent: --track is the default due to
> > > auto-vivify when the user specifies nothing but a branch name that
> > > doesn't exist yet, but when the user realizes the branch doesn't exist
> > > yet and asks to have it created then suddenly tracking is not the
> > > default??
> >
> > I don't think --track is default anymore (maybe I haven't updated the
> > man page correctly). The dwim behavior is only activated in
> > switch-branch when you specify --guess to reduce the amount of magic
> > we throw at the user. With that in mind, do we still hide
> > --track/--no-track from switch-branch?
>
> Ooh, you're adding --guess?  Cool, that addresses my concerns, just in
> a different manner.

> > > I'm not sure what's best, but here's some food for thought:
> > >
> > >
> > >    git switch-branch <branch>
> > > switches to <branch>, if it exists.  Error cases:
> > >   * If <branch> isn't actually a branch but a <tag> or
> > > <remote-tracking-branch> or <revision>, error out and suggest using
> > > --detach.
> > >   * If <branch> isn't actually a branch but there is a similarly named
> > > <remote-tracking-branch> (e.g. origin/<branch>), then suggest using
> > > -c.
> >
> > I would make these advice so I can hide them. Or if I manage to make
> > all these hints one line then I'll make it unconditional.
> >
> > >   git switch-branch -c <branch>
> > > creates <branch> and, if a relevant-remote-tracking branch exists,
> > > base the branch on that revision and set the new branch up to track
> >
> > Hmm.. this is a bit magical and could be surprising. If I create (and
> > switch to) a new branch foo, I don't necessarily mean tracking
> > origin/foo (I may not even think about origin/foo when I type the
> > command). So tentatively no.
>
> Yeah, if you're adding --guess then I'm happy.  I do think, though,
> that if the user runs switch-branch to a branch that doesn't exist, we
> should check if there is an associated remote-tracking branch so that
> we can provide a better error message and help users learn about
> --guess.  (Also, will there be a short -g form?)

> > > > +-f::
> > > > +--force::
> > > > +       Proceed even if the index or the working tree differs from
> > > > +       HEAD.  This is used to throw away local changes.
> > >
> > > Haven't thought through this thoroughly, but do we really need an
> > > option for that instead of telling users to 'git reset --hard HEAD'
> > > before switching branches if they want their stuff thrown away?
> >
> > For me it's just a bit more convenient. Hit an error when switching
> > branch? Recall the command from bash history, stick -f in it and run.
> > Elsewhere I think both Junio and Thomas (or maybe only Junio) suggests
> > moving the "git reset" functionality without moving HEAD to one of
> > these commands, which goes the opposite direction...
>
> Fair enough.

> > > > +--orphan <new_branch>::
> > > > +       Create a new 'orphan' branch, named <new_branch>, started from
> > > > +       <start_point> and switch to it.  The first commit made on this
> > >
> > > What??  started from <start_point>?  The whole point of --orphan is
> > > you have no parent, i.e. no start point.  Also, why does the
> > > explanation reference an argument that wasn't in the immediately
> > > preceding synopsis?
> >
> > I guess bad phrasing. It should be "switch to <start_point> first,
> > then prepare the worktree so that the first commit will have no
> > parent". Or something along that line.
> >
> > You should really review git-checkout.txt btw ;-)
>
> I did after writing several of these comments, and yeah, it really
> needs a clean up.  Seems like something someone would do when writing
> a (partial) replacement or simplified alternative.  ;-)

> > > > +       new branch will have no parents and it will be the root of a new
> > > > +       history totally disconnected from all the other branches and
> > > > +       commits.
> > > > ++
> > > > +The index and the working tree are adjusted as if you had previously run
> > > > +"git checkout <start_point>".  This allows you to start a new history
> > > > +that records a set of paths similar to <start_point> by easily running
> > > > +"git commit -a" to make the root commit.
> > > > ++
> > > > +This can be useful when you want to publish the tree from a commit
> > > > +without exposing its full history. You might want to do this to publish
> > > > +an open source branch of a project whose current tree is "clean", but
> > > > +whose full history contains proprietary or otherwise encumbered bits of
> > > > +code.
> > > > ++
> > > > +If you want to start a disconnected history that records a set of paths
> > > > +that is totally different from the one of <start_point>, then you should
> > > > +clear the index and the working tree right after creating the orphan
> > > > +branch by running "git rm -rf ." from the top level of the working tree.
> > > > +Afterwards you will be ready to prepare your new files, repopulating the
> > > > +working tree, by copying them from elsewhere, extracting a tarball, etc.
> > >
> > > Ick.  Seems overly complex.  I'd rather that --orphan defaulted to
> > > clearing the index and working tree, and that one would need to pass
> > > HEAD for <start_point> if you wanted to start out with all those other
> > > files.  That would certainly make the explanation a little clearer to
> > > users, and more natural when they start experimenting with it.
> > >
> > > However, --orphan is pretty special case.  Do we perhaps want to leave
> > > it out of this new command and only include it in checkout?
> >
> > I started this by simply splitting git-checkout in two commands that,
> > combined, can do everything git-checkout can. Then suggestions to have
> > better default came in and I think we started to drift further to
> > _removing_ options and falling back to git-checkout.
> >
> > I think we could still keep "complicated" options as long as they are
> > clearly described and don't surprise users until they figure them out.
> > That way I don't have to go back to git-checkout and deal with all the
> > ambiguation it creates.
>
> Fair enough...though I think it may make sense to also review the
> complicated options and determine if they are overly complicated.  I
> think --orphan qualifies (I stumbled with it a bit for years the
> occasional time I needed to use it), and my small suggestion above
> would simplify both it and its description.  We should probably also
> consider just removing <start_point> as an acceptable argument to
> --orphan; if people want files from some revision after creating an
> orphan branch that's a simple extra command.

> On Tue, Dec 4, 2018 at 6:43 PM Elijah Newren <newren@gmail.com> wrote:
>> > > > +--ours::
>> > > > +--theirs::
>> ...
>> go away.  Maybe it can still be fixed (I haven't dug too deeply into
>> it), but if so, the only fix needed here would be to remove this long
>> explanation about why the tool gets things totally backward.
>
> Aha. I' not really deep in this merge business to know if stages 2 and
> 3 can be swapped. This is right up your alley. I'll just leave it to
> you.

> I'm actually still not sure how to move it here (I guess 'here' is
> restore-files since we won't move HEAD). All the --mixed, --merge and
> --hard are confusing. But maybe we could just make 'git restore-files
> --from HEAD -f :/" behave just like "git reset --hard HEAD" (but with
> some safety net) But we can leave it for discussion in the next round.

>
> Duy Nguyen <pclouds@gmail.com> writes:
>
> > On Tue, Dec 4, 2018 at 6:43 PM Elijah Newren <newren@gmail.com> wrote:
> >> > > > +--ours::
> >> > > > +--theirs::
> >> ...
> >> go away.  Maybe it can still be fixed (I haven't dug too deeply into
> >> it), but if so, the only fix needed here would be to remove this long
> >> explanation about why the tool gets things totally backward.
> >
> > Aha. I' not really deep in this merge business to know if stages 2 and
> > 3 can be swapped. This is right up your alley. I'll just leave it to
> > you.
>
> Please don't show stage#2 and stage#3 swapped to the end user,
> unless that is protected behind an option (not per-repo config).
> It is pretty much ingrained that stage#2 is what came from the
> commit that will become the first parent of the commit being
> prepared, and changing it without an explicit command line option
> will break tools.

> > I'm actually still not sure how to move it here (I guess 'here' is
> > restore-files since we won't move HEAD). All the --mixed, --merge and
> > --hard are confusing. But maybe we could just make 'git restore-files
> > --from HEAD -f :/" behave just like "git reset --hard HEAD" (but with
> > some safety net) But we can leave it for discussion in the next round.
>
> Perhaps you two should pay a bit closer attention to what Thomas
> Gummerer is working on.  I've touched above in my earlier comments,
> too, e.g.  <xmqqefb3mhrs.fsf@gitster-ct.c.googlers.com>

>> My single biggest worry about this whole series is that I'm worried
>> you're perpetuating and even further ingraining one of the biggest
>> usability problems with checkout: people suggest and use it for
>> reverting/restoring paths to a previous version, but it doesn't do
>> that:
>
> ...
>
>  git restore-files --from=master~10 Documentation/

>> Also, the fact that we're trying to make a simpler command makes me
>> think that removing the auto-vivify behavior from the default and
>> adding a simple flag which users can pass to request will allow this
>> part of the documentation to be hidden behind the appropriate flag,
>> which may make it easier for users to compartmentalize the command and
>> it's options, enabling them to learn as they go.
>
> Sounds good. I don't know a good name for this new option though so
> unless anybody comes up with some suggestion, I'll just disable
> checkout.defaultRemote in switch-branch. If it comes back as a new
> option, it can always be added later.

>> > +-f::
>> > +--force::
>> > +       Proceed even if the index or the working tree differs from
>> > +       HEAD.  This is used to throw away local changes.
>>
>> Haven't thought through this thoroughly, but do we really need an
>> option for that instead of telling users to 'git reset --hard HEAD'
>> before switching branches if they want their stuff thrown away?
>
> For me it's just a bit more convenient. Hit an error when switching
> branch? Recall the command from bash history, stick -f in it and run.
> Elsewhere I think both Junio and Thomas (or maybe only Junio) suggests
> moving the "git reset" functionality without moving HEAD to one of
> these commands, which goes the opposite direction...

>> > +--orphan <new_branch>::
>> > +       Create a new 'orphan' branch, named <new_branch>, started from
>> > +       <start_point> and switch to it.  The first commit made on this
>>
>> What??  started from <start_point>?  The whole point of --orphan is
>> you have no parent, i.e. no start point.  Also, why does the
>> explanation reference an argument that wasn't in the immediately
>> preceding synopsis?
>
> I guess bad phrasing. It should be "switch to <start_point> first,
> then prepare the worktree so that the first commit will have no
> parent". Or something along that line.

>
> Duy Nguyen <pclouds@gmail.com> writes:
>
> >> My single biggest worry about this whole series is that I'm worried
> >> you're perpetuating and even further ingraining one of the biggest
> >> usability problems with checkout: people suggest and use it for
> >> reverting/restoring paths to a previous version, but it doesn't do
> >> that:
> >
> > ...
> >
> >  git restore-files --from=master~10 Documentation/
>
> The "single biggest worry" could be due to Elijah not being aware of
> other recent discussions.  My understanding of the plan is
>
>  - "git checkout" will learn a new "--[no-]overlay" option, where
>    the current behaviour, i.e. "take paths in master~10 that match
>    pathspec Documentation/, and overlay them on top of what is in
>    the index and the working tree", is explained as "the overlay
>    mode" and stays to be the default.  With "checkout --no-overlay
>    master~10 Documentation/", the command will become "replace paths
>    in the current index and the working tree that match the pathspec
>    Documentation/ with paths in master~10 that match pathspec
>    Documentation/".
>
>  - "git restore-files --from=<tree> <pathspec>" by default will use
>    "--no-overlay" semantics, but the users can still use "--overlay"
>    from the command line as an option.
>
> So "restore-files" would become truly "restore the state of
> Documentation/ to match that of master~10", I would think.

> >> Also, the fact that we're trying to make a simpler command makes me
> >> think that removing the auto-vivify behavior from the default and
> >> adding a simple flag which users can pass to request will allow this
> >> part of the documentation to be hidden behind the appropriate flag,
> >> which may make it easier for users to compartmentalize the command and
> >> it's options, enabling them to learn as they go.
> >
> > Sounds good. I don't know a good name for this new option though so
> > unless anybody comes up with some suggestion, I'll just disable
> > checkout.defaultRemote in switch-branch. If it comes back as a new
> > option, it can always be added later.
>
> Are you two discussing the "checkout --guess" option?  I am somewhat
> lost here.

> >> > +-f::
> >> > +--force::
> >> > +       Proceed even if the index or the working tree differs from
> >> > +       HEAD.  This is used to throw away local changes.
> >>
> >> Haven't thought through this thoroughly, but do we really need an
> >> option for that instead of telling users to 'git reset --hard HEAD'
> >> before switching branches if they want their stuff thrown away?
> >
> > For me it's just a bit more convenient. Hit an error when switching
> > branch? Recall the command from bash history, stick -f in it and run.
> > Elsewhere I think both Junio and Thomas (or maybe only Junio) suggests
> > moving the "git reset" functionality without moving HEAD to one of
> > these commands, which goes the opposite direction...
>
> Isn't there a huge difference?  "checkout --force <other-branch>"
> needs to clobber only the changes that are involved in the switch,
> i.e. if your README.txt is the same between master and maint while
> Makefile is different, after editing both files while on master, you
> can not "switch-branch" to maint without doing something to Makefile
> (i.e. either discard your local change or wiggle your local change
> to the context of 'maint' with "checkout -m").  But you can carry
> the changes to README.txt while checking out 'maint' branch.
> Running "git reset --hard HEAD" would mean that you will lose the
> changes to README.txt as well.

> >> > +--orphan <new_branch>::
> >> > +       Create a new 'orphan' branch, named <new_branch>, started from
> >> > +       <start_point> and switch to it.  The first commit made on this
> >>
> >> What??  started from <start_point>?  The whole point of --orphan is
> >> you have no parent, i.e. no start point.  Also, why does the
> >> explanation reference an argument that wasn't in the immediately
> >> preceding synopsis?
> >
> > I guess bad phrasing. It should be "switch to <start_point> first,
> > then prepare the worktree so that the first commit will have no
> > parent". Or something along that line.
>
> It should be a <tree-ish>, no?  It is not a "point" in history, but
> is "start with this tree".

> v3 sees switch-branch go back to switch-branch (in v2 it was
> checkout-branch). checkout-files is also renamed restore-files (v1 was
> restore-paths). Hopefully we won't see another rename.
>
> I'll try to summarize the differences between the new commands and
> 'git checkout' down here, but you're welcome to just head to 07/14 and
> read the new man pages.
>
> 'git switch-branch'
>
> - does not "do nothing", you have to either switch branch, create a
>   new branch, or detach. "git switch-branch" with no arguments is
>   rejected.
>
> - implicit detaching is rejected. If you need to detach, you need to
>   give --detach. Or stick to 'git checkout'.
>
> - -b/-B is renamed to -c/-C with long option names
>
> - of course does not accept pathspec
>
> 'git restore-files'
>
> - takes a ref from --from argument, not as a free ref. As a result,
>   '--' is no longer needed. All non-option arguments are pathspec
>
> - pathspec is mandatory, you can't do "git restore-files" without any
>   pathspec.
>
> - I just remember -p which is allowed to take no pathspec :( I'll fix
>   it later.
>
> - Two more fancy features (the "git checkout --index" being the
>   default mode and the backup log for accidental overwrites) are of
>   course still missing. But they are coming.
>
> I did not go replace "detached HEAD" with "unnamed branch" (or "no
> branch") everywhere because I think a unique term is still good to
> refer to this concept. Or maybe "no branch" is good enough. I dunno.

> On Thu, Nov 29 2018, Nguyễn Thái Ngọc Duy wrote:
>
>> v3 sees switch-branch go back to switch-branch (in v2 it was
>> checkout-branch). checkout-files is also renamed restore-files (v1 was
>> restore-paths). Hopefully we won't see another rename.
>>
>> I'll try to summarize the differences between the new commands and
>> 'git checkout' down here, but you're welcome to just head to 07/14 and
>> read the new man pages.
>>
>> 'git switch-branch'
>>
>> - does not "do nothing", you have to either switch branch, create a
>>   new branch, or detach. "git switch-branch" with no arguments is
>>   rejected.
>>
>> - implicit detaching is rejected. If you need to detach, you need to
>>   give --detach. Or stick to 'git checkout'.
>>
>> - -b/-B is renamed to -c/-C with long option names
>>
>> - of course does not accept pathspec
>>
>> 'git restore-files'
>>
>> - takes a ref from --from argument, not as a free ref. As a result,
>>   '--' is no longer needed. All non-option arguments are pathspec
>>
>> - pathspec is mandatory, you can't do "git restore-files" without any
>>   pathspec.
>>
>> - I just remember -p which is allowed to take no pathspec :( I'll fix
>>   it later.
>>
>> - Two more fancy features (the "git checkout --index" being the
>>   default mode and the backup log for accidental overwrites) are of
>>   course still missing. But they are coming.
>>
>> I did not go replace "detached HEAD" with "unnamed branch" (or "no
>> branch") everywhere because I think a unique term is still good to
>> refer to this concept. Or maybe "no branch" is good enough. I dunno.
>
> I finally tracked down
> https://redfin.engineering/two-commits-that-wrecked-the-user-experience-of-git-f0075b77eab1
> which I'd remembered reading and couldn't find again in these
> discussions. Re-reading it while one may not 100% agree with the
> author's opinion, it's an interesting rabbit hole.
>
> I also didn't know about EasyGit, or that Elijah Newren had written
> it. I haven't seen him chime in on this series, and would be interested
> to see what he thinks about it.
>
> Re the naming question in
> https://public-inbox.org/git/87o9abzv46.fsf@evledraar.gmail.com/ &
> seeing that eg-switch exists, I wonder if just s/switch-branch/switch/
> makes more sense.
>
> Assuming greenfield development (which we definitely don't have), I
> don't like the "restore-files" name, but the alternative that makes
> sense is "checkout". Then this "--from" argument could become "git
> checkout-tree <treeish> -- <pathspec>", and we'd have:
>
>     git switch <branchish>
>     git checkout <pathspec>
>     git checkout-tree <treeish> -- <pathspec>
>
> Or maybe that sucks, anyway what I was going to suggest is *if* others
> think that made sense as a "if we designed git today" endgame whether we
> could have an opt-in setting where you set e.g. core.uiVersion=3 (in
> anticipation of Git 3.0) and you'd get that behavior. There could be
> some other setting where core.uiVersion would use the old behavior (or
> with another setting, only warn) if we weren't connected to a terminal.
>
> I.e. I'm thinking of this as step #2 in a #3 step series. Where this is
> the fully backwards compatible UI improvement, but someone who'd
> e.g. use EasyGit or didn't have backwards compatibility concerns could
> enable step #3 and opt-in to a mode where we'd fixed a bunch of UI warts
> in a backwards-incompatible way.
>
> What would that mode look like? I'd to work on piling that on top of
> this :)

> On Nov 29, 2018, at 3:05 PM, Ævar Arnfjörð Bjarmason <avarab@gmail.com> wrote:
> 
> 
> On Thu, Nov 29 2018, Nguyễn Thái Ngọc Duy wrote:
> 
>> v3 sees switch-branch go back to switch-branch (in v2 it was
>> checkout-branch). checkout-files is also renamed restore-files (v1 was
>> restore-paths). Hopefully we won't see another rename.
>> 
>> I'll try to summarize the differences between the new commands and
>> 'git checkout' down here, but you're welcome to just head to 07/14 and
>> read the new man pages.
>> 
>> 'git switch-branch'
>> 
>> - does not "do nothing", you have to either switch branch, create a
>>  new branch, or detach. "git switch-branch" with no arguments is
>>  rejected.
>> 
>> - implicit detaching is rejected. If you need to detach, you need to
>>  give --detach. Or stick to 'git checkout'.
>> 
>> - -b/-B is renamed to -c/-C with long option names
>> 
>> - of course does not accept pathspec
>> 
>> 'git restore-files'
>> 
>> - takes a ref from --from argument, not as a free ref. As a result,
>>  '--' is no longer needed. All non-option arguments are pathspec
>> 
>> - pathspec is mandatory, you can't do "git restore-files" without any
>>  pathspec.
>> 
>> - I just remember -p which is allowed to take no pathspec :( I'll fix
>>  it later.
>> 
>> - Two more fancy features (the "git checkout --index" being the
>>  default mode and the backup log for accidental overwrites) are of
>>  course still missing. But they are coming.
>> 
>> I did not go replace "detached HEAD" with "unnamed branch" (or "no
>> branch") everywhere because I think a unique term is still good to
>> refer to this concept. Or maybe "no branch" is good enough. I dunno.
> 
> I finally tracked down
> https://redfin.engineering/two-commits-that-wrecked-the-user-experience-of-git-f0075b77eab1
> which I'd remembered reading and couldn't find again in these
> discussions. Re-reading it while one may not 100% agree with the
> author's opinion, it's an interesting rabbit hole.
> 
> I also didn't know about EasyGit, or that Elijah Newren had written
> it. I haven't seen him chime in on this series, and would be interested
> to see what he thinks about it.
> 
> Re the naming question in
> https://public-inbox.org/git/87o9abzv46.fsf@evledraar.gmail.com/ &
> seeing that eg-switch exists, I wonder if just s/switch-branch/switch/
> makes more sense.
> 
> Assuming greenfield development (which we definitely don't have), I
> don't like the "restore-files" name, but the alternative that makes
> sense is "checkout". Then this "--from" argument could become "git
> checkout-tree <treeish> -- <pathspec>", and we'd have:
> 
>    git switch <branchish>
>    git checkout <pathspec>
>    git checkout-tree <treeish> -- <pathspec>
> 
> Or maybe that sucks, anyway what I was going to suggest is *if* others
> think that made sense as a "if we designed git today" endgame whether we
> could have an opt-in setting where you set e.g. core.uiVersion=3 (in
> anticipation of Git 3.0) and you'd get that behavior. There could be
> some other setting where core.uiVersion would use the old behavior (or
> with another setting, only warn) if we weren't connected to a terminal.
> 
> I.e. I'm thinking of this as step #2 in a #3 step series. Where this is
> the fully backwards compatible UI improvement, but someone who'd
> e.g. use EasyGit or didn't have backwards compatibility concerns could
> enable step #3 and opt-in to a mode where we'd fixed a bunch of UI warts
> in a backwards-incompatible way.
> 
> What would that mode look like? I'd to work on piling that on top of
> this :)

> On Nov 29, 2018, at 3:05 PM, Ævar Arnfjörð Bjarmason <avarab@gmail.com> wrote:
> 
> 
> On Thu, Nov 29 2018, Nguyễn Thái Ngọc Duy wrote:
> 
>> v3 sees switch-branch go back to switch-branch (in v2 it was
>> checkout-branch). checkout-files is also renamed restore-files (v1 was
>> restore-paths). Hopefully we won't see another rename.
>> 
>> I'll try to summarize the differences between the new commands and
>> 'git checkout' down here, but you're welcome to just head to 07/14 and
>> read the new man pages.
>> 
>> 'git switch-branch'
>> 
>> - does not "do nothing", you have to either switch branch, create a
>>  new branch, or detach. "git switch-branch" with no arguments is
>>  rejected.
>> 
>> - implicit detaching is rejected. If you need to detach, you need to
>>  give --detach. Or stick to 'git checkout'.
>> 
>> - -b/-B is renamed to -c/-C with long option names
>> 
>> - of course does not accept pathspec
>> 
>> 'git restore-files'
>> 
>> - takes a ref from --from argument, not as a free ref. As a result,
>>  '--' is no longer needed. All non-option arguments are pathspec
>> 
>> - pathspec is mandatory, you can't do "git restore-files" without any
>>  pathspec.
>> 
>> - I just remember -p which is allowed to take no pathspec :( I'll fix
>>  it later.
>> 
>> - Two more fancy features (the "git checkout --index" being the
>>  default mode and the backup log for accidental overwrites) are of
>>  course still missing. But they are coming.
>> 
>> I did not go replace "detached HEAD" with "unnamed branch" (or "no
>> branch") everywhere because I think a unique term is still good to
>> refer to this concept. Or maybe "no branch" is good enough. I dunno.
> 
> I finally tracked down
> https://redfin.engineering/two-commits-that-wrecked-the-user-experience-of-git-f0075b77eab1
> which I'd remembered reading and couldn't find again in these
> discussions. Re-reading it while one may not 100% agree with the
> author's opinion, it's an interesting rabbit hole.
> 
> I also didn't know about EasyGit, or that Elijah Newren had written
> it. I haven't seen him chime in on this series, and would be interested
> to see what he thinks about it.
> 
> Re the naming question in
> https://public-inbox.org/git/87o9abzv46.fsf@evledraar.gmail.com/ &
> seeing that eg-switch exists, I wonder if just s/switch-branch/switch/
> makes more sense.
> 
> Assuming greenfield development (which we definitely don't have), I
> don't like the "restore-files" name, but the alternative that makes
> sense is "checkout". Then this "--from" argument could become "git
> checkout-tree <treeish> -- <pathspec>", and we'd have:
> 
>    git switch <branchish>
>    git checkout <pathspec>
>    git checkout-tree <treeish> -- <pathspec>
> 
> Or maybe that sucks, anyway what I was going to suggest is *if* others
> think that made sense as a "if we designed git today" endgame whether we
> could have an opt-in setting where you set e.g. core.uiVersion=3 (in
> anticipation of Git 3.0) and you'd get that behavior. There could be
> some other setting where core.uiVersion would use the old behavior (or
> with another setting, only warn) if we weren't connected to a terminal.
> 
> I.e. I'm thinking of this as step #2 in a #3 step series. Where this is
> the fully backwards compatible UI improvement, but someone who'd
> e.g. use EasyGit or didn't have backwards compatibility concerns could
> enable step #3 and opt-in to a mode where we'd fixed a bunch of UI warts
> in a backwards-incompatible way.
> 
> What would that mode look like? I'd to work on piling that on top of
> this :)

>
> Other thoughts on a global UI rethink:
>
> One of the most common complaints I hear about git is the conceptual difficulty required in undoing changes. https://ohshitgit.com/
>
> > Git is hard: screwing up is easy, and figuring out how to fix your mistakes is fucking impossible. Git documentation has this chicken and egg problem where you can't search for how to get yourself out of a mess, unless you *already know the name of the thing you need to know about* in order to fix your problem.
>
> A significant fraction of the top-voted questions on StackOverflow are about undoing changes. https://stackoverflow.com/questions/tagged/git
>
> What if there were a 'git undo' command that could unify the answers to all of these questions?
>
> git undo stage
> git undo rm
> git undo edit (checkout files from the stage)
>
> git undo commit (prompt the user whether to revert or reset)
> git undo reset
> git undo checkout
>
> git undo merge
> git undo pull
> git undo push (prompt the user whether to force push back to the past or whether to revert pushed commits)
> git undo rebase
>
> git undo undo
>
> git undo clean
> git undo delete-branch
> git undo delete-stash
>
> Some of these would be trivial effort, but a lot of them would require fundamental changes in the way git operates. (You can't undo a clean right now because the files are just destroyed.)

> Assuming greenfield development (which we definitely don't have), I
> don't like the "restore-files" name, but the alternative that makes
> sense is "checkout". Then this "--from" argument could become "git
> checkout-tree <treeish> -- <pathspec>", and we'd have:
>
>     git switch <branchish>
>     git checkout <pathspec>
>     git checkout-tree <treeish> -- <pathspec>
>
> Or maybe that sucks, anyway what I was going to suggest is *if* others
> think that made sense as a "if we designed git today" endgame whether we
> could have an opt-in setting where you set e.g. core.uiVersion=3 (in
> anticipation of Git 3.0) and you'd get that behavior. There could be
> some other setting where core.uiVersion would use the old behavior (or
> with another setting, only warn) if we weren't connected to a terminal.

> On Fri, Nov 30, 2018 at 12:05 AM Ævar Arnfjörð Bjarmason
> <avarab@gmail.com> wrote:
>> Assuming greenfield development (which we definitely don't have), I
>> don't like the "restore-files" name, but the alternative that makes
>> sense is "checkout". Then this "--from" argument could become "git
>> checkout-tree <treeish> -- <pathspec>", and we'd have:
>>
>>     git switch <branchish>
>>     git checkout <pathspec>
>>     git checkout-tree <treeish> -- <pathspec>
>>
>> Or maybe that sucks, anyway what I was going to suggest is *if* others
>> think that made sense as a "if we designed git today" endgame whether we
>> could have an opt-in setting where you set e.g. core.uiVersion=3 (in
>> anticipation of Git 3.0) and you'd get that behavior. There could be
>> some other setting where core.uiVersion would use the old behavior (or
>> with another setting, only warn) if we weren't connected to a terminal.
>
> core.uiVersion is a big no no to me. I don't want to go to someone's
> terminal, type something and have a total surprise because they set
> different ui version. If you want a total UI redesign, go with a new
> prefix, like "ng" (for new git) or something instead of "git".

>
>
> On Fri, Nov 30 2018, Duy Nguyen wrote:
>
> > On Fri, Nov 30, 2018 at 12:05 AM Ævar Arnfjörð Bjarmason
> > <avarab@gmail.com> wrote:
> >> Assuming greenfield development (which we definitely don't have), I
> >> don't like the "restore-files" name, but the alternative that makes
> >> sense is "checkout". Then this "--from" argument could become "git
> >> checkout-tree <treeish> -- <pathspec>", and we'd have:
> >>
> >>     git switch <branchish>
> >>     git checkout <pathspec>
> >>     git checkout-tree <treeish> -- <pathspec>
> >>
> >> Or maybe that sucks, anyway what I was going to suggest is *if* others
> >> think that made sense as a "if we designed git today" endgame whether we
> >> could have an opt-in setting where you set e.g. core.uiVersion=3 (in
> >> anticipation of Git 3.0) and you'd get that behavior. There could be
> >> some other setting where core.uiVersion would use the old behavior (or
> >> with another setting, only warn) if we weren't connected to a terminal.
> >
> > core.uiVersion is a big no no to me. I don't want to go to someone's
> > terminal, type something and have a total surprise because they set
> > different ui version. If you want a total UI redesign, go with a new
> > prefix, like "ng" (for new git) or something instead of "git".
>
> I don't think that's a viable way forward. First, we're not talking
> about a total change of the UI. Most the main porcelain will stay the
> same. So we'd have a "ng" that's >98% the same UI, and then if we
> discover warts in in 10 years we'd like to fix then what do wo do? Ship
> "nng" and so forth?

> We already have this UI problem with various config variables that
> change things. I think we should just solve this general issue by a
> combination of:
>
>  a) Accepting that over the long term we will have Git's UI changing,
>     sometimes in breaking ways (with sensible phase-in), hopefully for
>     the better. E.g. we had this with "git-init" v.s. "git init". This
>     is similar, there'd be an error due to ambiguity with a "hint"
>     saying use the new thing if you e.g. feed "git checkout" a branch
>     name.

> - pathspec is mandatory, you can't do "git restore-files" without any
>   pathspec.
>
> - I just remember -p which is allowed to take no pathspec :( I'll fix
>   it later.

>
> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
>
> > 'git switch-branch'
> >
> > - implicit detaching is rejected. If you need to detach, you need to
> >   give --detach. Or stick to 'git checkout'.
>
> OK.  Is "auto-vivify the named branch based on a remote-tracking"
> also rejected, as it is a confusing behaviour that is a too subtle
> and implicit, just like the detaching head is, and require --guess
> or sticking to 'git checkout'?  I think it should.

> > - -b/-B is renamed to -c/-C with long option names
>
> I did not expect that these two are the only options that would be
> out of place with the command name split, but presumably you looked
> at all options for both of the two new commands to see if they made
> sense in the new context?

>>
>> OK.  Is "auto-vivify the named branch based on a remote-tracking"
>> also rejected, as it is a confusing behaviour that is a too subtle
>> and implicit, just like the detaching head is, and require --guess
>> or sticking to 'git checkout'?  I think it should.
>
> This touches the "remote" concept which I think is another confusing
> thing for new people (your "master" is not the same as the server's
> "master", aka origin/master) and perhaps this dwim thing helps.
> Frankly I don't do dwim much so I don't know if it's that often used.

> 
> I am unsure about the wisdom of calling it "--index", though.
> 
> The "--index" option is "the command can work only on the index, or
> only on the working tree files, or on both the index and the working
> tree files, and this option tells it to work in the 'both the index
> and the working tree files' mode", but when "restore-files" touches
> paths, it always modifies both the index and the working tree, so
> the "--index" option does not capture the differences well in this
> context [*1*].  As I saw this was described as "not using the usual
> 'overlay' semantics [*2*]", perhaps --overlay/--no-overlay option
> that defaults to --no-overlay is easier to explain.

>     side note 1.  I think the original mention of "--index" came in
>     the context of contrasting "git reset" with "git checkout".
>     "git reset (--hard|--mixed) -- <pathspec>" (that does not move
>     HEAD), which does not but perhaps should exist, is very much
>     like "git checkout -- <pathspec>", and if "reset" were written
>     after the "--index/--cached" convention was established, "reset
>     --hard" would have called "reset --index" while "reset --mixed"
>     would have been "reset --cached" (i.e. only work on the index
>     and not on the working tree).  And "reset --index <directory>"
>     would have worked by removing paths in <directory> that are not
>     in the HEAD and updating paths in <directory> that are in the
>     HEAD, i.e. identical to the non overlay behaviour proposed for
>     the "git checkout" command.  So calling the non overlay mode
>     "--index" makes sense in the context of discussing "git reset",
>     and not in the context of "git checkout".
> 
>     side note 2.  "git checkout <tree-ish> <pathspec>" grabs entries
>     from the <tree-ish> that patch <pathspec> and adds them to the
>     index and checks them out to the working tree.  If the original
>     index has entries that match <pathspec> but do not appear in
>     <tree-ish>, they are left in the result.  That is "overlaying
>     what was taken from the <tree-ish> on top of what is in the
>     index".
> 
> Having said all that, I will not be looking at the series until 2.20
> final.  And I hope more people do the same to concentrate on helping
> us prevent the last minute glitch slipping in the final release.
> 
> Thanks.

> I'll try to summarize the differences between the new commands and
> 'git checkout' down here, but you're welcome to just head to 07/14 and
> read the new man pages.
>
> 'git switch-branch'
>
> - does not "do nothing", you have to either switch branch, create a
>   new branch, or detach. "git switch-branch" with no arguments is
>   rejected.
>
> - implicit detaching is rejected. If you need to detach, you need to
>   give --detach. Or stick to 'git checkout'.
>
> - -b/-B is renamed to -c/-C with long option names
>
> - of course does not accept pathspec
>
> 'git restore-files'
>
> - takes a ref from --from argument, not as a free ref. As a result,
>   '--' is no longer needed. All non-option arguments are pathspec
>
> - pathspec is mandatory, you can't do "git restore-files" without any
>   pathspec.
>
> - I just remember -p which is allowed to take no pathspec :( I'll fix
>   it later.

> - Two more fancy features (the "git checkout --index" being the
>   default mode and the backup log for accidental overwrites) are of
>   course still missing. But they are coming.
>
> I did not go replace "detached HEAD" with "unnamed branch" (or "no
> branch") everywhere because I think a unique term is still good to
> refer to this concept. Or maybe "no branch" is good enough. I dunno.

>
> On Thu, Nov 29, 2018 at 2:01 PM Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> >
> > v3 sees switch-branch go back to switch-branch (in v2 it was
> > checkout-branch). checkout-files is also renamed restore-files (v1 was
> > restore-paths). Hopefully we won't see another rename.
>
> I started reading through the patches.  I also tried to apply them
> locally, but they had conflicts or missing base file version on both
> master and next.  What version did you base it on?

> > - Two more fancy features (the "git checkout --index" being the
> >   default mode and the backup log for accidental overwrites) are of
> >   course still missing. But they are coming.
> >
> > I did not go replace "detached HEAD" with "unnamed branch" (or "no
> > branch") everywhere because I think a unique term is still good to
> > refer to this concept. Or maybe "no branch" is good enough. I dunno.
>
> I personally like "unnamed branch", but "no branch" would still be
> better than "detached HEAD".

>
> On Tue, Dec 4, 2018 at 2:29 AM Elijah Newren <newren@gmail.com> wrote:
> >
> > On Thu, Nov 29, 2018 at 2:01 PM Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> > >
> > > v3 sees switch-branch go back to switch-branch (in v2 it was
> > > checkout-branch). checkout-files is also renamed restore-files (v1 was
> > > restore-paths). Hopefully we won't see another rename.
> >
> > I started reading through the patches.  I also tried to apply them
> > locally, but they had conflicts or missing base file version on both
> > master and next.  What version did you base it on?
>
> I think nd/checkout-dwim-fix because of a non-trivial conflict there
> (but I don't remember when I noticed it and rebased on that). Anyway
> you can get the whole series at
>
> https://gitlab.com/pclouds/git/tree/switch-branch-and-checkout-files
>
> It fixes some of your comments already, a couple of bug fixes here and
> there and in a good-enough shape that I start actually using it.

> > > - Two more fancy features (the "git checkout --index" being the
> > >   default mode and the backup log for accidental overwrites) are of
> > >   course still missing. But they are coming.
> > >
> > > I did not go replace "detached HEAD" with "unnamed branch" (or "no
> > > branch") everywhere because I think a unique term is still good to
> > > refer to this concept. Or maybe "no branch" is good enough. I dunno.
> >
> > I personally like "unnamed branch", but "no branch" would still be
> > better than "detached HEAD".
>
> Haven't really worked on killing the term "detached HEAD" yet. But I
> noticed the other day that git-branch reports
>
> * (HEAD detached from 703266f6e4)
>
> and I didn't know how to rephrase that. I guess "unnamed branch from
> 703266f6e4" is probably good enough but my old-timer brain screams no.

> > > > - Two more fancy features (the "git checkout --index" being the
> > > >   default mode and the backup log for accidental overwrites) are of
> > > >   course still missing. But they are coming.
> > > >
> > > > I did not go replace "detached HEAD" with "unnamed branch" (or "no
> > > > branch") everywhere because I think a unique term is still good to
> > > > refer to this concept. Or maybe "no branch" is good enough. I dunno.
> > >
> > > I personally like "unnamed branch", but "no branch" would still be
> > > better than "detached HEAD".
> >
> > Haven't really worked on killing the term "detached HEAD" yet. But I
> > noticed the other day that git-branch reports
> >
> > * (HEAD detached from 703266f6e4)
> >
> > and I didn't know how to rephrase that. I guess "unnamed branch from
> > 703266f6e4" is probably good enough but my old-timer brain screams no.
>
> Perhaps "* (On an unnamed branch, at 703266f6e4)"?

>
> On Tue, Dec 4, 2018 at 6:45 PM Elijah Newren <newren@gmail.com> wrote:
> > > > > - Two more fancy features (the "git checkout --index" being the
> > > > >   default mode and the backup log for accidental overwrites) are of
> > > > >   course still missing. But they are coming.
> > > > >
> > > > > I did not go replace "detached HEAD" with "unnamed branch" (or "no
> > > > > branch") everywhere because I think a unique term is still good to
> > > > > refer to this concept. Or maybe "no branch" is good enough. I dunno.
> > > >
> > > > I personally like "unnamed branch", but "no branch" would still be
> > > > better than "detached HEAD".
> > >
> > > Haven't really worked on killing the term "detached HEAD" yet. But I
> > > noticed the other day that git-branch reports
> > >
> > > * (HEAD detached from 703266f6e4)
> > >
> > > and I didn't know how to rephrase that. I guess "unnamed branch from
> > > 703266f6e4" is probably good enough but my old-timer brain screams no.
> >
> > Perhaps "* (On an unnamed branch, at 703266f6e4)"?
>
> This 703266f6e4 is the fork point. Once you start adding more commits
> on top of this unnamed branch, I find it hard to define it "at"
> 703266f6e4 anymore. "forked from 703266f6e4" (or even starting/growing
> from...) is probably clearest but also a bit longer.

>
> On Tue, Dec 4, 2018 at 10:22 AM Duy Nguyen <pclouds@gmail.com> wrote:
> >
> > On Tue, Dec 4, 2018 at 6:45 PM Elijah Newren <newren@gmail.com> wrote:
> > > > > > - Two more fancy features (the "git checkout --index" being the
> > > > > >   default mode and the backup log for accidental overwrites) are of
> > > > > >   course still missing. But they are coming.
> > > > > >
> > > > > > I did not go replace "detached HEAD" with "unnamed branch" (or "no
> > > > > > branch") everywhere because I think a unique term is still good to
> > > > > > refer to this concept. Or maybe "no branch" is good enough. I dunno.
> > > > >
> > > > > I personally like "unnamed branch", but "no branch" would still be
> > > > > better than "detached HEAD".
> > > >
> > > > Haven't really worked on killing the term "detached HEAD" yet. But I
> > > > noticed the other day that git-branch reports
> > > >
> > > > * (HEAD detached from 703266f6e4)
> > > >
> > > > and I didn't know how to rephrase that. I guess "unnamed branch from
> > > > 703266f6e4" is probably good enough but my old-timer brain screams no.
> > >
> > > Perhaps "* (On an unnamed branch, at 703266f6e4)"?
> >
> > This 703266f6e4 is the fork point. Once you start adding more commits
> > on top of this unnamed branch, I find it hard to define it "at"
> > 703266f6e4 anymore. "forked from 703266f6e4" (or even starting/growing
> > from...) is probably clearest but also a bit longer.
>
> It reports the fork point rather than the commit HEAD points to?  Ah,
> I guess I never payed that close of attention before.  I actually
> think "on an unnamed branch" is good enough, but if others gain value
> from the extra info, then I understand the conundrum.  I'm not sure
> what the use or rationale is for the fork point, though, so I feel
> slightly at a loss to try to describe this extra piece of info.

> Haven't really worked on killing the term "detached HEAD" yet. But I
> noticed the other day that git-branch reports
>
> * (HEAD detached from 703266f6e4)
>
> and I didn't know how to rephrase that. I guess "unnamed branch from
> 703266f6e4" is probably good enough but my old-timer brain screams no.

>
> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
>
> > One of the problems with "git checkout" is that it does so many
> > different things and could confuse people specially when we fail to
> > handle ambiguation correctly.
>
> You would have realized that this is way too noisy if you ran "make
> test", which may have spewed something like this on the screen.

> [19:09:19] t4120-apply-popt.sh ................................ ok     1624 ms ( 0.26 usr  0.21 sys +  5.31 cusr  3.51 csys =  9.29 CPU)
> [19:09:20] t9164-git-svn-dcommit-concurrent.sh ................ skipped: Perl SVN libraries not found or unusable
> [19:09:20] t1310-config-default.sh ............................ ok      177 ms ( 0.07 usr  0.01 sys +  0.89 cusr  0.66 csys =  1.63 CPU)
> ===(   20175;154  1297/?  155/?  6/?  3/3  2/?  4/?  4/?  3/?  5... )===Checked out 1 path out of the index
> Checked out 1 path out of the index
> Checked out 1 path out of the index
> Checked out 1 path out of the index
> Checked out 1 path out of the index
> [19:09:20] t1408-packed-refs.sh ............................... ok      310 ms ( 0.06 usr  0.00 sys +  0.69 cusr  0.52 csys =  1.27 CPU)
> [19:09:20] t0025-crlf-renormalize.sh .......................... ok      246 ms ( 0.03 usr  0.01 sys +  0.34 cusr  0.22 csys =  0.60 CPU)
>
> I am very tempted to suggest to treat this as a training wheel and
> enable only when checkout.showpathcount is set to true, or something
> like that.

> One of the problems with "git checkout" is that it does so many
> different things and could confuse people specially when we fail to
> handle ambiguation correctly.
>
> One way to help with that is tell the user what sort of operation is
> actually carried out. When switching branches, we always print
> something unless --quiet, either
>
>  - "HEAD is now at ..."
>  - "Reset branch ..."
>  - "Already on ..."
>  - "Switched to and reset ..."
>  - "Switched to a new branch ..."
>  - "Switched to branch ..."
>
> Checking out paths however is silent. Print something so that if we
> got the user intention wrong, they won't waste too much time to find
> that out. For the remaining cases of checkout we now print either
>
>  - "Checked out ... paths out of the index"
>  - "Checked out ... paths out of <abbrev hash>"
>
> Since the purpose of printing this is to help disambiguate. Only do it
> when "--" is missing.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  v2 updates the messages a bit but it does not check isatty or add
>  --count-paths, for consistency reason with how messages are printed
>  in the branch switching case.
>  
>  Consistency is not always a good reason to follow. But I haven't
>  seen a strong reason to go against it.

> One small bug I saw since this was merged is that the message that
> is given when unmerging, i.e.
>
>         git merge other-branch   ;# conflicts
>         git checkout --m <path>
>
> is misleading.  It gives the same "checked out ... out of the index",
> but it should be made a lot more distinct, perhaps "unmerged N paths".

>
> I think users have problems with detached heads for several reasons:
>
> 1. Users often enter the detached head state unexpectedly (for example, by mistyping a "checkout" command or not understanding its multipurpose nature, or as a side-effect of running a submodule command). The change described here will go in the right direction towards addressing this, since you won't be able to accidentally detach your head by mistyping checkout. If detaching was always an intentional action by the user, it would be much less intimidating.
>
> 2. Git shows a lot of scary error messages when running in a detached head state. They tell you you're doing something dangerous, which dissuades users from experimenting with the feature. IMO, it would be better to replace the scary warning messages with instructions on where to get more information about detached heads (and those instructions should frontload info on how to reattach to a branch and how to recover commits from the reflog).
>
> 3. When in a detached head state, a lot of commands add extra confirmation prompts, which are unnecessary and intimidating.
>
> Basically, the current user interface implies to the user that a detached head is an error condition they'll need to recover from rather than the normal and useful mode of working that it is.
>
>   - Stefan
>
> On Wed, Nov 28, 2018 at 12:01 PM Duy Nguyen <pclouds@gmail.com> wrote:
>>
>> On Tue, Nov 27, 2018 at 5:53 PM Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
>> >
>> > v2 is just a bit better to look at than v1. This is by no means final.
>> > If you think the command name is bad, the default behavior should
>> > change, or something else, speak up. It's still very "RFC".
>> >
>> > v2 breaks down the giant patch in v1 and starts adding some changes in
>> > these new commands:
>> >
>> > - restore-paths is renamed to checkout-paths. I wrote I didn't like
>> >   "checkout" because of completion conflict. But who am I kidding,
>> >   I'll use aliases anyway. "-files" instead of "-paths" because we
>> >   already have ls-files.
>> > - both commands will not accept no arguments. There is no "git
>> >   checkout" equivalent.
>> > - ambiguation rules are now aware that "switch-branch" for example
>> >   can't take pathspec...
>>
>> Another thing. Since we start with a clean slate, should we do
>> something about detached HEAD in this switch-branch command (or
>> whatever its name will be)?
>>
>> This is usually a confusing concept to new users and I've seen some
>> users have a hard time getting out of it. I'm too comfortable with
>> detached HEAD to see this from new user's perspective and a better way
>> to deal with it.
>> --
>> Duy