[PATCH 3/5] describe: catch unborn branch in describe_blob()
- From
Jeff King <peff@peff.net>
- Date
- Aug 18, 2025, 21:01 UTC
- Message-ID
- <20250818210154.GC1024556@coredump.intra.peff.net>
- In-Reply-To
- <20250818205812.GA1018043@coredump.intra.peff.net>
When describing a blob, we search for it by traversing from HEAD. We do this by feeding the name HEAD to setup_revisions(). But if we are on an unborn branch, this will fail with a confusing message:
$ git describe $blob fatal: ambiguous argument 'HEAD': unknown revision or path not in the working tree. Use '--' to separate paths from revisions, like this: 'git <command> [<revision>...] -- [<file>...]'
It is OK for this to be an error (we cannot find $blob in an empty traversal, so we'd eventually complain about that). But the error message could be more helpful.
Let's resolve HEAD ourselves and pass the resolved object id to setup_revisions(). If resolving fails, then we can print a more useful message.
Signed-off-by: Jeff King <peff@peff.net> --- builtin/describe.c | 8 +++++++- t/t6120-describe.sh | 8 ++++++++ 2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/builtin/describe.c b/builtin/describe.c index 06e413d937..f7bea3c8c5 100644 --- a/builtin/describe.c +++ b/builtin/describe.c @@ -518,10 +518,16 @@ static void describe_blob(const struct object_id *oid, struct strbuf *dst) { struct rev_info revs; struct strvec args = STRVEC_INIT; + struct object_id head_oid; struct process_commit_data pcd = { *null_oid(the_hash_algo), oid, dst, &revs}; + if (repo_get_oid(the_repository, "HEAD", &head_oid)) + die(_("cannot search for blob '%s' on an unborn branch"), + oid_to_hex(oid)); + strvec_pushl(&args, "internal: The first arg is not parsed", - "--objects", "--in-commit-order", "--reverse", "HEAD", + "--objects", "--in-commit-order", "--reverse", + oid_to_hex(&head_oid), NULL); repo_init_revisions(the_repository, &revs, NULL); diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh index 470631d17d..feec57bcbc 100755 --- a/t/t6120-describe.sh +++ b/t/t6120-describe.sh @@ -415,6 +415,14 @@ test_expect_success 'describe an unreachable blob' ' test_grep "blob .$blob. not reachable from HEAD" actual ' +test_expect_success 'describe blob on an unborn branch' ' + oldbranch=$(git symbolic-ref HEAD) && + test_when_finished "git symbolic-ref HEAD $oldbranch" && + git symbolic-ref HEAD refs/heads/does-not-exist && + test_must_fail git describe test-blob 2>actual && + test_grep "cannot search .* on an unborn branch" actual +' + test_expect_success ULIMIT_STACK_SIZE 'name-rev works in a deep repo' ' i=1 && while test $i -lt 8000
-- 2.51.0.326.gecbb38d78e