revert: allow single-pick in the middle of cherry-pick sequence

After messing up a difficult conflict resolution in the middle of a
cherry-pick sequence, it can be useful to be able to

	git checkout HEAD . && git cherry-pick that-one-commit

to restart the conflict resolution. The current code however errors out
saying that another cherry-pick is already in progress.

Suggested-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/revert.c b/builtin/revert.c
index f7f4bb35774db6445348b41c61dd2c27883d2381..5785ff9941e698eee7b6e480676a411d52076078 100644 (file)
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -1072,6 +1072,12 @@ static int sequencer_continue(struct replay_opts *opts)
        return pick_commits(todo_list, opts);
 }
 
+static int single_pick(struct commit *cmit, struct replay_opts *opts)
+{
+       setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
+       return do_pick_commit(cmit, opts);
+}
+
 static int pick_revisions(struct replay_opts *opts)
 {
        struct commit_list *todo_list = NULL;
@@ -1096,6 +1102,26 @@ static int pick_revisions(struct replay_opts *opts)
        if (opts->subcommand == REPLAY_CONTINUE)
                return sequencer_continue(opts);
 
+       /*
+        * If we were called as "git cherry-pick <commit>", just
+        * cherry-pick/revert it, set CHERRY_PICK_HEAD /
+        * REVERT_HEAD, and don't touch the sequencer state.
+        * This means it is possible to cherry-pick in the middle
+        * of a cherry-pick sequence.
+        */
+       if (opts->revs->cmdline.nr == 1 &&
+           opts->revs->cmdline.rev->whence == REV_CMD_REV &&
+           opts->revs->no_walk &&
+           !opts->revs->cmdline.rev->flags) {
+               struct commit *cmit;
+               if (prepare_revision_walk(opts->revs))
+                       die(_("revision walk setup failed"));
+               cmit = get_revision(opts->revs);
+               if (!cmit || get_revision(opts->revs))
+                       die("BUG: expected exactly one commit from walk");
+               return single_pick(cmit, opts);
+       }
+
        /*
         * Start a new cherry-pick/ revert sequence; but
         * first, make sure that an existing one isn't in

diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 56c95ec18c5061ef8ac760503dd6fd16f72779c3..98a27a23eaa22231ac33b0a32b6a18a1aa54b500 100755 (executable)
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -50,6 +50,18 @@ test_expect_success 'cherry-pick persists data on failure' '
        test_path_is_file .git/sequencer/opts
 '
 
+test_expect_success 'cherry-pick mid-cherry-pick-sequence' '
+       pristine_detach initial &&
+       test_must_fail git cherry-pick base..anotherpick &&
+       test_cmp_rev picked CHERRY_PICK_HEAD &&
+       # "oops, I forgot that these patches rely on the change from base"
+       git checkout HEAD foo &&
+       git cherry-pick base &&
+       git cherry-pick picked &&
+       git cherry-pick --continue &&
+       git diff --exit-code anotherpick
+'
+
 test_expect_success 'cherry-pick persists opts correctly' '
        pristine_detach initial &&
        test_must_fail git cherry-pick -s -m 1 --strategy=recursive -X patience -X ours base..anotherpick &&