Re: [PATCH v4 2/3] worktree add: add --orphan flag

>
> > +static int make_worktree_orphan(const char * ref, const struct add_opts *opts,
> > +				struct strvec *child_env)
> > +{
> > +	int ret;
>
> You can avoid this variable entirely....
>
> > +
> > +	validate_new_branchname(ref, &symref, 0);
> > +	strvec_pushl(&cp.args, "symbolic-ref", "HEAD", symref.buf, NULL);
>
> ...by just calling strbuf_release(&symref); right after this line, we'll
> never need it again, and the strvec will have its own copy.
>
> > +	if (opts->quiet)
> > +		strvec_push(&cp.args, "--quiet");
> > +	strvec_pushv(&cp.env, child_env->v);
>
> So:
>
> > +	ret = run_command(&cp);
> > +	strbuf_release(&symref);
> > +	return ret;
>
> We don't have to carry the "ret" here, and can just do:
>
> 	return run_command(&cp);
>

>
> > +	struct strbuf symref = STRBUF_INIT;
> > +	struct child_process cp = CHILD_PROCESS_INIT;
> > +	cp.git_cmd = 1;
>
> (aside: We usually split up variables & decls, I think this is better
> right before the run_command() line).

> > +}
> > +
> >  static int add_worktree(const char *path, const char *refname,
> >  			const struct add_opts *opts)
> >  {
> > @@ -393,8 +415,9 @@ static int add_worktree(const char *path, const char *refname,
> >  			die_if_checked_out(symref.buf, 0);
> >  	}
> >  	commit = lookup_commit_reference_by_name(refname);
> > -	if (!commit)
> > +	if (!commit && !opts->orphan) {
> >  		die(_("invalid reference: %s"), refname);
> > +	}
>
> We don't add {}'s for one-statement if's like this, see
> CodingGuidelines. So skip the {}'s.
>

> >
> >  	name = worktree_basename(path, &len);
> >  	strbuf_add(&sb, name, path + len - name);
> > @@ -482,10 +505,10 @@ static int add_worktree(const char *path, const char *refname,
> >  	strvec_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);
> >  	cp.git_cmd = 1;
> >
> > -	if (!is_branch)
> > +	if (!is_branch && commit) {
> >  		strvec_pushl(&cp.args, "update-ref", "HEAD",
> >  			     oid_to_hex(&commit->object.oid), NULL);
> > -	else {
> > +	} else {
>
> Here that style change is good, even if it inflates the diff size a
> litte bit with the while-at-it fixu-up.
>
> > +	/*
> > +	 * When creating a new branch, new_branch now contains the branch to
> > +	 * create.
> > +	 *
> > +	 * Past this point, new_branch_force can be treated solely as a
> > +	 * boolean flag to indicate whether `-B` was selected.
> > +	 */
> >  	if (new_branch_force) {
> >  		struct strbuf symref = STRBUF_INIT;
> >
>
> I think I commented on this commentary in an earlier round. IMO it could
> just be omitted, as the code is rather self-explanatory.
>
> To the extent that it isn't this commentary just makes things more
> confusing, at least to my reading. It's not explaining what the code is
> doing now, because the very next line after this context (omitted here) is:
>
> 	new_branch = new_branch_force
>
> So we're saying it "can be treated solely as a boolean flag", but it
> isn't being treated as such by the code now.
>
> And the "new_branch now contains the branch to create" is also
> inaccurate, we're about to make it true with that assignment, but (and
> again, I don't think a comment is needed at all) *if* we think that's
> worth commenting on then surely the first paragraph of the comment
> should be split off, and come just before that assignment.

>
> > -	if (new_branch) {
> > +	if (opts.orphan) {
> > +		branch = new_branch;
> > +	} else if (!lookup_commit_reference_by_name(branch)) {
> > +		/*
> > +		 * If `branch` does not reference a valid commit, a new
> > +		 * worktree (and/or branch) cannot be created based off of it.
> > +		 */
>
> I think with the advice added in 3/3 this comment can also just be
> omitted here, as the end result is that the comment will be
> re-explaining something which should be obvious from the inline advice
> string (and if it isn't, that inline string needs improving).

>
> > -test_expect_success '"add" -b/-B mutually exclusive' '
> > -	test_must_fail git worktree add -b poodle -B poodle bamboo main
> > -'
> > -
> > -test_expect_success '"add" -b/--detach mutually exclusive' '
> > -	test_must_fail git worktree add -b poodle --detach bamboo main
> > -'
> > +# Helper function to test mutually exclusive options.
> > +test_wt_add_excl() {
> > +	local opts="$@" &&
> > +	test_expect_success "'worktree add' with '$opts' has mutually exclusive options" '
> > +		test_must_fail git worktree add $opts
> > +	'
> > +}
> >
> > -test_expect_success '"add" -B/--detach mutually exclusive' '
> > -	test_must_fail git worktree add -B poodle --detach bamboo main
> > -'
> > +test_wt_add_excl -b poodle -B poodle bamboo main
> > +test_wt_add_excl -b poodle --orphan poodle bamboo
> > +test_wt_add_excl -b poodle --detach bamboo main
> > +test_wt_add_excl -B poodle --detach bamboo main
> > +test_wt_add_excl -B poodle --detach bamboo main
> > +test_wt_add_excl -B poodle --orphan poodle bamboo
> > +test_wt_add_excl --orphan poodle --detach bamboo
> > +test_wt_add_excl --orphan poodle --no-checkout bamboo
> > +test_wt_add_excl --orphan poodle bamboo main
>
> It's good to see this as a helper function, but I think it would be nice
> to have this split up into its own pre-refactoring commit.
>
> As here we're changing some existing tests that are per-se unrelated,
> just so that they can use this new helper.
>
> This commit could then add tests that use the helper, and which are new
> for --orphan.