When using git-cherry-pick(1) with `--allow-empty` while on an unborn
branch, an error is thrown. This is inconsistent with the same
cherry-pick when `--allow-empty` is not specified.
Detect unborn branches in `is_index_unchanged`. When on an unborn
branch, use the `empty_tree` as the tree to compare against.
Add a new test to cover this scenario. While modelled off of the
existing 'cherry-pick on unborn branch' test, some improvements can be
made:
- Use `git switch --orphan unborn` instead of `git checkout --orphan
unborn` to avoid the need for a separate `rm -rf *` call
- Avoid using `--quiet` in the `git diff` call to make debugging easier
in the event of a failure. Use simply `--exit-code` instead.
Make these improvements to the existing test as well as the new test.
Helped-by: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
Helped-by: Junio C Hamano <gitster@xxxxxxxxx>
Signed-off-by: Brian Lyles <brianmlyles@xxxxxxxxx>
---
Changes from v4:
- Use single-line block comment style since the comment is a single line
of text.
- Wrap two longer lines of code.
sequencer.c | 43 +++++++++++++++++++++++------------
t/t3501-revert-cherry-pick.sh | 14 +++++++++---
2 files changed, 39 insertions(+), 18 deletions(-)
diff --git a/sequencer.c b/sequencer.c
index f49a871ac0..e3f0a52f72 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -770,29 +770,42 @@ static struct object_id *get_cache_tree_oid(struct index_state *istate)
static int is_index_unchanged(struct repository *r)
{
struct object_id head_oid, *cache_tree_oid;
+ const struct object_id *head_tree_oid;
struct commit *head_commit;
struct index_state *istate = r->index;
+ const char *head_name;
+
+ if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL)) {
+ /* Check to see if this is an unborn branch */
+ head_name = resolve_ref_unsafe("HEAD",
+ RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+ &head_oid, NULL);
+ if (!head_name ||
+ !starts_with(head_name, "refs/heads/") ||
+ !is_null_oid(&head_oid))
+ return error(_("could not resolve HEAD commit"));
+ head_tree_oid = the_hash_algo->empty_tree;
+ } else {
+ head_commit = lookup_commit(r, &head_oid);
- if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
- return error(_("could not resolve HEAD commit"));
-
- head_commit = lookup_commit(r, &head_oid);
+ /*
+ * If head_commit is NULL, check_commit, called from
+ * lookup_commit, would have indicated that head_commit is not
+ * a commit object already. repo_parse_commit() will return failure
+ * without further complaints in such a case. Otherwise, if
+ * the commit is invalid, repo_parse_commit() will complain. So
+ * there is nothing for us to say here. Just return failure.
+ */
+ if (repo_parse_commit(r, head_commit))
+ return -1;
- /*
- * If head_commit is NULL, check_commit, called from
- * lookup_commit, would have indicated that head_commit is not
- * a commit object already. repo_parse_commit() will return failure
- * without further complaints in such a case. Otherwise, if
- * the commit is invalid, repo_parse_commit() will complain. So
- * there is nothing for us to say here. Just return failure.
- */
- if (repo_parse_commit(r, head_commit))
- return -1;
+ head_tree_oid = get_commit_tree_oid(head_commit);
+ }
if (!(cache_tree_oid = get_cache_tree_oid(istate)))
return -1;
- return oideq(cache_tree_oid, get_commit_tree_oid(head_commit));
+ return oideq(cache_tree_oid, head_tree_oid);
}
static int write_author_script(const char *message)
diff --git a/t/t3501-revert-cherry-pick.sh b/t/t3501-revert-cherry-pick.sh
index aeab689a98..af73227512 100755
--- a/t/t3501-revert-cherry-pick.sh
+++ b/t/t3501-revert-cherry-pick.sh
@@ -104,11 +104,19 @@ test_expect_success 'revert forbidden on dirty working tree' '
'
test_expect_success 'cherry-pick on unborn branch' '
- git checkout --orphan unborn &&
+ git switch --orphan unborn &&
git rm --cached -r . &&
- rm -rf * &&
git cherry-pick initial &&
- git diff --quiet initial &&
+ git diff --exit-code initial &&
+ test_cmp_rev ! initial HEAD
+'
+
+test_expect_success 'cherry-pick on unborn branch with --allow-empty' '
+ git checkout --detach &&
+ git branch -D unborn &&
+ git switch --orphan unborn &&
+ git cherry-pick initial --allow-empty &&
+ git diff --exit-code initial &&
test_cmp_rev ! initial HEAD
'
--
2.43.2
