revert: introduce --abort to cancel a failed cherry-pick

[git.git] / builtin / revert.c

diff --git a/builtin/revert.c b/builtin/revert.c
index f5ba67a50578b257c713b0d69d5c022f4e5f483b..70a5fbb672f14bec432447b37ce9b012577fe510 100644 (file)
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -40,7 +40,12 @@ static const char * const cherry_pick_usage[] = {
 };
 
 enum replay_action { REVERT, CHERRY_PICK };
-enum replay_subcommand { REPLAY_NONE, REPLAY_REMOVE_STATE, REPLAY_CONTINUE };
+enum replay_subcommand {
+       REPLAY_NONE,
+       REPLAY_REMOVE_STATE,
+       REPLAY_CONTINUE,
+       REPLAY_ROLLBACK
+};
 
 struct replay_opts {
        enum replay_action action;
@@ -135,9 +140,11 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
        const char *me = action_name(opts);
        int remove_state = 0;
        int contin = 0;
+       int rollback = 0;
        struct option options[] = {
                OPT_BOOLEAN(0, "quit", &remove_state, "end revert or cherry-pick sequence"),
                OPT_BOOLEAN(0, "continue", &contin, "resume revert or cherry-pick sequence"),
+               OPT_BOOLEAN(0, "abort", &rollback, "cancel revert or cherry-pick sequence"),
                OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
                OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
                OPT_NOOP_NOARG('r', NULL),
@@ -173,6 +180,7 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
        verify_opt_mutually_compatible(me,
                                "--quit", remove_state,
                                "--continue", contin,
+                               "--abort", rollback,
                                NULL);
 
        /* Set the subcommand */
@@ -180,6 +188,8 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
                opts->subcommand = REPLAY_REMOVE_STATE;
        else if (contin)
                opts->subcommand = REPLAY_CONTINUE;
+       else if (rollback)
+               opts->subcommand = REPLAY_ROLLBACK;
        else
                opts->subcommand = REPLAY_NONE;
 
@@ -188,8 +198,12 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
                char *this_operation;
                if (opts->subcommand == REPLAY_REMOVE_STATE)
                        this_operation = "--quit";
-               else
+               else if (opts->subcommand == REPLAY_CONTINUE)
                        this_operation = "--continue";
+               else {
+                       assert(opts->subcommand == REPLAY_ROLLBACK);
+                       this_operation = "--abort";
+               }
 
                verify_opt_compatible(me, this_operation,
                                "--no-commit", opts->no_commit,
@@ -850,7 +864,7 @@ static int create_seq_dir(void)
 
        if (file_exists(seq_dir)) {
                error(_("a cherry-pick or revert is already in progress"));
-               advise(_("try \"git cherry-pick (--continue | --quit)\""));
+               advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
                return -1;
        }
        else if (mkdir(seq_dir, 0777) < 0)
@@ -873,6 +887,71 @@ static void save_head(const char *head)
                die(_("Error wrapping up %s."), head_file);
 }
 
+static int reset_for_rollback(const unsigned char *sha1)
+{
+       const char *argv[4];    /* reset --merge <arg> + NULL */
+       argv[0] = "reset";
+       argv[1] = "--merge";
+       argv[2] = sha1_to_hex(sha1);
+       argv[3] = NULL;
+       return run_command_v_opt(argv, RUN_GIT_CMD);
+}
+
+static int rollback_single_pick(void)
+{
+       unsigned char head_sha1[20];
+
+       if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
+           !file_exists(git_path("REVERT_HEAD")))
+               return error(_("no cherry-pick or revert in progress"));
+       if (!resolve_ref("HEAD", head_sha1, 0, NULL))
+               return error(_("cannot resolve HEAD"));
+       if (is_null_sha1(head_sha1))
+               return error(_("cannot abort from a branch yet to be born"));
+       return reset_for_rollback(head_sha1);
+}
+
+static int sequencer_rollback(struct replay_opts *opts)
+{
+       const char *filename;
+       FILE *f;
+       unsigned char sha1[20];
+       struct strbuf buf = STRBUF_INIT;
+
+       filename = git_path(SEQ_HEAD_FILE);
+       f = fopen(filename, "r");
+       if (!f && errno == ENOENT) {
+               /*
+                * There is no multiple-cherry-pick in progress.
+                * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
+                * a single-cherry-pick in progress, abort that.
+                */
+               return rollback_single_pick();
+       }
+       if (!f)
+               return error(_("cannot open %s: %s"), filename,
+                                               strerror(errno));
+       if (strbuf_getline(&buf, f, '\n')) {
+               error(_("cannot read %s: %s"), filename, ferror(f) ?
+                       strerror(errno) : _("unexpected end of file"));
+               goto fail;
+       }
+       if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
+               error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
+                       filename);
+               goto fail;
+       }
+       if (reset_for_rollback(sha1))
+               goto fail;
+       strbuf_release(&buf);
+       fclose(f);
+       return 0;
+fail:
+       strbuf_release(&buf);
+       fclose(f);
+       return -1;
+}
+
 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 {
        const char *todo_file = git_path(SEQ_TODO_FILE);
@@ -977,6 +1056,8 @@ static int pick_revisions(struct replay_opts *opts)
                remove_sequencer_state(1);
                return 0;
        }
+       if (opts->subcommand == REPLAY_ROLLBACK)
+               return sequencer_rollback(opts);
        if (opts->subcommand == REPLAY_CONTINUE) {
                if (!file_exists(git_path(SEQ_TODO_FILE)))
                        return error(_("No %s in progress"), action_name(opts));