commit: add a reword suboption to --fixup

`git commit --fixup=reword:<commit>` aliases
`--fixup=amend:<commit> --only`, where it creates an empty "amend!"
commit that will reword <commit> without changing its contents when
it is rebased with `--autosquash`.

Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Charvi Mendiratta <charvi077@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/commit.c b/builtin/commit.c
index 9697bba10bf45fd7ad2575bc35fec7feacd78ee6..b17e6e32f85d327bcc4e1300d334af8a8d88c01e 100644 (file)
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1188,6 +1188,19 @@ static void finalize_deferred_config(struct wt_status *s)
                s->ahead_behind_flags = AHEAD_BEHIND_FULL;
 }
 
+static void check_fixup_reword_options(int argc, const char *argv[]) {
+       if (whence != FROM_COMMIT) {
+               if (whence == FROM_MERGE)
+                       die(_("You are in the middle of a merge -- cannot reword."));
+               else if (is_from_cherry_pick(whence))
+                       die(_("You are in the middle of a cherry-pick -- cannot reword."));
+       }
+       if (argc)
+               die(_("cannot combine reword option of --fixup with path '%s'"), *argv);
+       if (patch_interactive || interactive || all || also || only)
+               die(_("reword option of --fixup is mutually exclusive with --patch/--interactive/--all/--include/--only"));
+}
+
 static int parse_and_validate_options(int argc, const char *argv[],
                                      const struct option *options,
                                      const char * const usage[],
@@ -1269,8 +1282,9 @@ static int parse_and_validate_options(int argc, const char *argv[],
                 * We limit --fixup's suboptions to only alpha characters.
                 * If the first character after a run of alpha is colon,
                 * then the part before the colon may be a known suboption
-                * name `amend` or a misspelt suboption name. In this case,
-                * we treat it as --fixup=<suboption>:<arg>.
+                * name like `amend` or `reword`, or a misspelt suboption
+                * name. In either case, we treat it as
+                * --fixup=<suboption>:<arg>.
                 *
                 * Otherwise, we are dealing with --fixup=<commit>.
                 */
@@ -1280,9 +1294,14 @@ static int parse_and_validate_options(int argc, const char *argv[],
                if (p > fixup_message && *p == ':') {
                        *p = '\0';
                        fixup_commit = p + 1;
-                       if (!strcmp("amend", fixup_message)) {
+                       if (!strcmp("amend", fixup_message) ||
+                           !strcmp("reword", fixup_message)) {
                                fixup_prefix = "amend";
                                allow_empty = 1;
+                               if (*fixup_message == 'r') {
+                                       check_fixup_reword_options(argc, argv);
+                                       only = 1;
+                               }
                        } else {
                                die(_("unknown option: --fixup=%s:%s"), fixup_message, fixup_commit);
                        }
@@ -1571,10 +1590,10 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
                OPT_STRING('c', "reedit-message", &edit_message, N_("commit"), N_("reuse and edit message from specified commit")),
                OPT_STRING('C', "reuse-message", &use_message, N_("commit"), N_("reuse message from specified commit")),
                /*
-                * TRANSLATORS: Leave "[amend:]" as-is, and
-                * only translate <commit>.
+                * TRANSLATORS: Leave "[(amend|reword):]" as-is,
+                * and only translate <commit>.
                 */
-               OPT_STRING(0, "fixup", &fixup_message, N_("[amend:]commit"), N_("use autosquash formatted message to fixup or amend specified commit")),
+               OPT_STRING(0, "fixup", &fixup_message, N_("[(amend|reword):]commit"), N_("use autosquash formatted message to fixup or amend/reword specified commit")),
                OPT_STRING(0, "squash", &squash_message, N_("commit"), N_("use autosquash formatted message to squash specified commit")),
                OPT_BOOL(0, "reset-author", &renew_authorship, N_("the commit is authored by me now (used with -C/-c/--amend)")),
                OPT_BOOL('s', "signoff", &signoff, N_("add a Signed-off-by trailer")),