From 3519492430ba26cadcdb215730a6c8e1bcf5b9cf Mon Sep 17 00:00:00 2001 From: Karthik Nayak Date: Thu, 23 Jan 2025 12:29:44 +0100 Subject: [PATCH] refs: fix creation of reflog entries for symrefs The commit 297c09eabb (refs: allow multiple reflog entries for the same refname, 2024-12-16) added logic to exit early in `lock_ref_for_update()` after obtaining the required lock. This was added as a performance optimization on a false assumption that no further processing was required for reflog-only updates. However the assumption was wrong. For a symref's reflog entry, the update needs to be populated with the old_oid value, but the early exit skipped this necessary step. This caused a bug in Git 2.48 in the files backend where target references of symrefs being updated would create a corrupted reflog entry for the symref since the old_oid is not populated. Everything the early exit skipped in the code path is necessary for both regular and symbolic ref, so eliminate the mistaken optimization, and also add a test to ensure that such an issue doesn't arise in the future. Reported-by: Nika Layzell Co-authored-by: Jeff King Signed-off-by: Jeff King Signed-off-by: Karthik Nayak Signed-off-by: Junio C Hamano --- refs/files-backend.c | 3 --- t/t1400-update-ref.sh | 9 +++++++++ 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/refs/files-backend.c b/refs/files-backend.c index 8953d1c6d3..1c0e24a855 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -2611,9 +2611,6 @@ static int lock_ref_for_update(struct files_ref_store *refs, update->backend_data = lock; - if (update->flags & REF_LOG_ONLY) - goto out; - if (update->type & REF_ISSYMREF) { if (update->flags & REF_NO_DEREF) { /* diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh index e2316f1dd4..29045aad43 100755 --- a/t/t1400-update-ref.sh +++ b/t/t1400-update-ref.sh @@ -2068,4 +2068,13 @@ do done +test_expect_success 'update-ref should also create reflog for HEAD' ' + test_commit to-rewind && + git rev-parse HEAD >expect && + head=$(git symbolic-ref HEAD) && + git update-ref --create-reflog "$head" HEAD~ && + git rev-parse HEAD@{1} >actual && + test_cmp expect actual +' + test_done