Re: [PATCH] rebase: add `--update-refs=interactive`

>
> In rebase-heavy workflows involving multiple interdependent feature
> branches, typing out `--update-refs` quickly becomes tiring, which
> can be mitigated with setting the `rebase.updateRefs` git-config option
> to perform update-refs by default.
>
> However, the utility of `rebase.updateRefs` is somewhat limited because
> you rarely want it in a non-interactive rebase (as it does not give you
> the chance to review the update-refs candidates, likely leading to
> updating refs that you didn't want updated -- I made quite an amount
> of mess by setting this option and subsequently forgetting about it).
>
> Try to find a middle ground by introducing a third value,
> `--update-refs=interactive` (and `rebase.updateRefs=interactive`)
> which means `--update-refs` when starting an interactive rebase and
> `--no-update-refs` otherwise. This option is primarily intended to be
> used in the gitconfig, but is also accepted on the command line
> for completeness.
>
> Signed-off-by: Ivan Shapovalov <intelfx@intelfx.name>
> ---
>  Documentation/config/rebase.txt |  7 +++-
>  Documentation/git-rebase.txt    |  8 +++-
>  builtin/rebase.c                | 72 +++++++++++++++++++++++++++++----
>  3 files changed, 77 insertions(+), 10 deletions(-)
>
> diff --git a/Documentation/config/rebase.txt b/Documentation/config/rebase.txt
> index c6187ab28b..d8bbaba69a 100644
> --- a/Documentation/config/rebase.txt
> +++ b/Documentation/config/rebase.txt
> @@ -24,7 +24,12 @@ rebase.autoStash::
>         Defaults to false.
>
>  rebase.updateRefs::
> -       If set to true enable `--update-refs` option by default.
> +       If set to true, enable the `--update-refs` option of
> +       linkgit:git-rebase[1] by default. When set to 'interactive',
> +       only enable `--update-refs` by default for interactive mode
> +       (equivalent to `--update-refs=interactive`).
> +       This option can be overridden by specifying any form of
> +       `--update-refs` on the command line.
>
>  rebase.missingCommitsCheck::
>         If set to "warn", git rebase -i will print a warning if some
> diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
> index b18cdbc023..ae6939588d 100644
> --- a/Documentation/git-rebase.txt
> +++ b/Documentation/git-rebase.txt
> @@ -647,12 +647,18 @@ rebase --continue` is invoked. Currently, you cannot pass
>
>  --update-refs::
>  --no-update-refs::
> +--update-refs=interactive::

>         Automatically force-update any branches that point to commits that
>         are being rebased. Any branches that are checked out in a worktree
>         are not updated in this way.
>  +
> +If `--update-refs=interactive` is specified, the behavior is equivalent to
> +`--update-refs` if the rebase is interactive and `--no-update-refs` otherwise.
> +(This is mainly useful as a configuration setting, although it might also be
> +of use in aliases.)
> ++
>  If the configuration variable `rebase.updateRefs` is set, then this option
> -can be used to override and disable this setting.
> +can be used to override or disable the configuration.
>  +
>  See also INCOMPATIBLE OPTIONS below.
>
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index 6c9eaf3788..57b456599b 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -129,10 +129,17 @@ struct rebase_options {
>         int reschedule_failed_exec;
>         int reapply_cherry_picks;
>         int fork_point;
> -       int update_refs;
> +       // UPDATE_REFS_{UNKNOWN,NO,ALWAYS} numeric values must never
> +       // change as post-option-parsing code works with {,config_}update_refs
> +       // as if they were ints
> +       enum {
> +               UPDATE_REFS_UNKNOWN = -1,
> +               UPDATE_REFS_NO = 0,
> +               UPDATE_REFS_ALWAYS = 1,
> +               UPDATE_REFS_INTERACTIVE,
> +       } update_refs, config_update_refs;
>         int config_autosquash;
>         int config_rebase_merges;
> -       int config_update_refs;
>  };
>
>  #define REBASE_OPTIONS_INIT {                          \
> @@ -150,8 +157,8 @@ struct rebase_options {
>                 .autosquash = -1,                       \
>                 .rebase_merges = -1,                    \
>                 .config_rebase_merges = -1,             \
> -               .update_refs = -1,                      \
> -               .config_update_refs = -1,               \
> +               .update_refs = UPDATE_REFS_UNKNOWN,     \
> +               .config_update_refs = UPDATE_REFS_UNKNOWN, \
>                 .strategy_opts = STRING_LIST_INIT_NODUP,\
>         }
>
> @@ -412,6 +419,18 @@ static void imply_merge(struct rebase_options *opts, const char *option)
>         }
>  }
>
> +static int coerce_update_refs(const struct rebase_options *opts, int update_refs)
> +{
> +       /* coerce "=interactive" into "no" rather than "not set" when not interactive
> +        * this way, `git -c rebase.updateRefs=yes rebase --update-refs=interactive [without -i]`
> +        * will not inherit the "yes" from the config */
> +       if (update_refs == UPDATE_REFS_INTERACTIVE)
> +               return (opts->flags & REBASE_INTERACTIVE_EXPLICIT)
> +                      ? UPDATE_REFS_ALWAYS
> +                      : UPDATE_REFS_NO;
> +       return update_refs;
> +}
> +
>  /* Returns the filename prefixed by the state_dir */
>  static const char *state_dir_path(const char *filename, struct rebase_options *opts)
>  {
> @@ -779,6 +798,17 @@ static void parse_rebase_merges_value(struct rebase_options *options, const char
>                 die(_("Unknown rebase-merges mode: %s"), value);
>  }
>
> +static int parse_update_refs_value(const char *value, const char *desc)
> +{
> +       int v = git_parse_maybe_bool(value);
> +       if (v >= 0)
> +               return v ? UPDATE_REFS_ALWAYS : UPDATE_REFS_NO;
> +       else if (!strcmp("interactive", value))
> +               return UPDATE_REFS_INTERACTIVE;
> +
> +       die(_("bad %s value '%s'; valid values are boolean or \"interactive\""), desc, value);
> +}
> +
>  static int rebase_config(const char *var, const char *value,
>                          const struct config_context *ctx, void *data)
>  {
> @@ -821,7 +851,8 @@ static int rebase_config(const char *var, const char *value,
>         }
>
>         if (!strcmp(var, "rebase.updaterefs")) {
> -               opts->config_update_refs = git_config_bool(var, value);
> +               opts->config_update_refs = parse_update_refs_value(value,
> +                       "rebase.updateRefs");
>                 return 0;
>         }
>
> @@ -1042,6 +1073,19 @@ static int parse_opt_rebase_merges(const struct option *opt, const char *arg, in
>         return 0;
>  }
>
> +static int parse_opt_update_refs(const struct option *opt, const char *arg, int unset)
> +{
> +       struct rebase_options *options = opt->value;
> +
> +       if (arg)
> +               options->update_refs = parse_update_refs_value(arg,
> +                       "--update-refs");
> +       else
> +               options->update_refs = unset ? UPDATE_REFS_NO : UPDATE_REFS_ALWAYS;
> +
> +       return 0;
> +}
> +
>  static void NORETURN error_on_missing_default_upstream(void)
>  {
>         struct branch *current_branch = branch_get(NULL);
> @@ -1187,9 +1231,11 @@ int cmd_rebase(int argc,
>                 OPT_BOOL(0, "autosquash", &options.autosquash,
>                          N_("move commits that begin with "
>                             "squash!/fixup! under -i")),
> -               OPT_BOOL(0, "update-refs", &options.update_refs,
> -                        N_("update branches that point to commits "
> -                           "that are being rebased")),
> +               OPT_CALLBACK_F(0, "update-refs", &options,
> +                       N_("(bool|interactive)"),
> +                       N_("update branches that point to commits "
> +                          "that are being rebased"),
> +                       PARSE_OPT_OPTARG, parse_opt_update_refs),
>                 { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
>                         N_("GPG-sign commits"),
>                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
> @@ -1528,6 +1574,16 @@ int cmd_rebase(int argc,
>         if (isatty(2) && options.flags & REBASE_NO_QUIET)
>                 strbuf_addstr(&options.git_format_patch_opt, " --progress");
>
> +       /* coerce --update-refs=interactive into yes or no.
> +        * we do it here because there's just too much code below that handles
> +        * {,config_}update_refs in one way or another and modifying it to
> +        * account for the new state would be too invasive.
> +        * all further code uses {,config_}update_refs as a tristate. */
> +       options.update_refs =
> +               coerce_update_refs(&options, options.update_refs);
> +       options.config_update_refs =
> +               coerce_update_refs(&options, options.config_update_refs);
> +
>         if (options.git_am_opts.nr || options.type == REBASE_APPLY) {
>                 /* all am options except -q are compatible only with --apply */
>                 for (i = options.git_am_opts.nr - 1; i >= 0; i--)
> --
> 2.48.1.5.g9188e14f140
>
>