commit: give correct advice for empty commit during a rebase

In dcb500dc16c (cherry-pick/revert: advise using --skip, 2019-07-02),
`git commit` learned to suggest to run `git cherry-pick --skip` when
trying to cherry-pick an empty patch.

However, it was overlooked that there are more conditions than just a
`git cherry-pick` when this advice is printed (which originally
suggested the neutral `git reset`): the same can happen during a rebase.

Let's suggest the correct command, even during a rebase.

While at it, we adjust more places in `builtin/commit.c` that
incorrectly assumed that the presence of a `CHERRY_PICK_HEAD` meant that
surely this must be a `cherry-pick` in progress.

Note: we take pains to handle the situation when a user runs a `git
cherry-pick` _during_ a rebase. This is quite valid (e.g. in an `exec`
line in an interactive rebase). On the other hand, it is not possible to
run a rebase during a cherry-pick, meaning: if both `rebase-merge/` and
`sequencer/` exist or CHERRY_PICK_HEAD and REBASE_HEAD point to the same
commit , we still want to advise to use `git cherry-pick --skip`.

Original-patch-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/wt-status.h b/wt-status.h
index e38e0942dc..73ab5d4da1 100644
--- a/wt-status.h
+++ b/wt-status.h
@@ -39,7 +39,8 @@ enum commit_whence {
 	FROM_COMMIT,     /* normal */
 	FROM_MERGE,      /* commit came from merge */
 	FROM_CHERRY_PICK_SINGLE, /* commit came from cherry-pick */
-	FROM_CHERRY_PICK_MULTI /* commit came from a sequence of cherry-picks */
+	FROM_CHERRY_PICK_MULTI, /* commit came from a sequence of cherry-picks */
+	FROM_REBASE_PICK /* commit came from a pick/reword/edit */
 };
 
 static inline int is_from_cherry_pick(enum commit_whence whence)
@@ -48,6 +49,11 @@ static inline int is_from_cherry_pick(enum commit_whence whence)
 		whence == FROM_CHERRY_PICK_MULTI;
 }
 
+static inline int is_from_rebase(enum commit_whence whence)
+{
+	return whence == FROM_REBASE_PICK;
+}
+
 struct wt_status_change_data {
 	int worktree_status;
 	int index_status;