rebase -r: don't write .git/MERGE_MSG when fast-forwarding
When fast-forwarding we do not create a new commit so .git/MERGE_MSG
is not removed and can end up seeding the message of a commit made
after the rebase has finished. Avoid writing .git/MERGE_MSG when we
are fast-forwarding by writing the file after the fast-forward
checks. Note that there are no changes to the fast-forward code, it is
simply moved.
Note that the way this change is implemented means we no longer write
the author script when fast-forwarding either. I believe this is safe
for the reasons below but it is a departure from what we do when
fast-forwarding a non-merge commit. If we reword the merge then 'git
commit --amend' will keep the authorship of the commit we're rewording
as it ignores GIT_AUTHOR_* unless --reset-author is passed. It will
also export the correct GIT_AUTHOR_* variables to any hooks and we
already test the authorship of the reworded commit. If we are not
rewording then we no longer call spilt_ident() which means we are no
longer checking the commit author header looks sane. However this is
what we already do when fast-forwarding non-merge commits in
skip_unnecessary_picks() so I don't think we're breaking any promises
by not checking the author here.
Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/sequencer.c b/sequencer.c
index cc8a361..c2cba5e 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -983,7 +983,8 @@ static int run_git_commit(const char *defmsg,
cmd.git_cmd = 1;
- if (is_rebase_i(opts) && read_env_script(&cmd.env_array)) {
+ if (is_rebase_i(opts) && !(!defmsg && (flags & AMEND_MSG)) &&
+ read_env_script(&cmd.env_array)) {
const char *gpg_opt = gpg_sign_opt_quoted(opts);
return error(_(staged_changes_advice),
@@ -3815,6 +3816,45 @@ static int do_merge(struct repository *r,
goto leave_merge;
}
+ /*
+ * If HEAD is not identical to the first parent of the original merge
+ * commit, we cannot fast-forward.
+ */
+ can_fast_forward = opts->allow_ff && commit && commit->parents &&
+ oideq(&commit->parents->item->object.oid,
+ &head_commit->object.oid);
+
+ /*
+ * If any merge head is different from the original one, we cannot
+ * fast-forward.
+ */
+ if (can_fast_forward) {
+ struct commit_list *p = commit->parents->next;
+
+ for (j = to_merge; j && p; j = j->next, p = p->next)
+ if (!oideq(&j->item->object.oid,
+ &p->item->object.oid)) {
+ can_fast_forward = 0;
+ break;
+ }
+ /*
+ * If the number of merge heads differs from the original merge
+ * commit, we cannot fast-forward.
+ */
+ if (j || p)
+ can_fast_forward = 0;
+ }
+
+ if (can_fast_forward) {
+ rollback_lock_file(&lock);
+ ret = fast_forward_to(r, &commit->object.oid,
+ &head_commit->object.oid, 0, opts);
+ if (flags & TODO_EDIT_MERGE_MSG)
+ goto fast_forward_edit;
+
+ goto leave_merge;
+ }
+
if (commit) {
const char *encoding = get_commit_output_encoding();
const char *message = logmsg_reencode(commit, NULL, encoding);
@@ -3864,45 +3904,6 @@ static int do_merge(struct repository *r,
}
}
- /*
- * If HEAD is not identical to the first parent of the original merge
- * commit, we cannot fast-forward.
- */
- can_fast_forward = opts->allow_ff && commit && commit->parents &&
- oideq(&commit->parents->item->object.oid,
- &head_commit->object.oid);
-
- /*
- * If any merge head is different from the original one, we cannot
- * fast-forward.
- */
- if (can_fast_forward) {
- struct commit_list *p = commit->parents->next;
-
- for (j = to_merge; j && p; j = j->next, p = p->next)
- if (!oideq(&j->item->object.oid,
- &p->item->object.oid)) {
- can_fast_forward = 0;
- break;
- }
- /*
- * If the number of merge heads differs from the original merge
- * commit, we cannot fast-forward.
- */
- if (j || p)
- can_fast_forward = 0;
- }
-
- if (can_fast_forward) {
- rollback_lock_file(&lock);
- ret = fast_forward_to(r, &commit->object.oid,
- &head_commit->object.oid, 0, opts);
- if (flags & TODO_EDIT_MERGE_MSG)
- goto fast_forward_edit;
-
- goto leave_merge;
- }
-
if (strategy || to_merge->next) {
/* Octopus merge */
struct child_process cmd = CHILD_PROCESS_INIT;
