Under normal circumstances, it shouldn't ever happen that a repository
has no HEAD reference. In fact, git-update-ref(1) would fail any request
to delete the HEAD reference, and a newly initialized repository always
pre-creates it, too.
But in the next commit, we are going to change git-clone(1) to partially
initialize the refdb just up to the point where remote helpers can find
the repository. With that change, we are going to run into a situation
where repositories have no refs at all.
Now there is a very particular edge case in this situation: when
preparing an empty ref transacton, we end up returning whatever value
`read_ref_without_reload()` returned to the caller. Under normal
conditions this would be fine: "HEAD" should usually exist, and thus the
function would return `0`. But if "HEAD" doesn't exist, the function
returns a positive value which we end up returning to the caller.
Fix this bug by resetting the return code to `0` and add a test.
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
refs/reftable-backend.c | 1 +
t/t0610-reftable-basics.sh | 13 +++++++++++++
2 files changed, 14 insertions(+)
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index a14f2ad7f4..45568818f0 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -821,6 +821,7 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
&head_referent, &head_type);
if (ret < 0)
goto done;
+ ret = 0;
for (i = 0; i < transaction->nr; i++) {
struct ref_update *u = transaction->updates[i];
diff --git a/t/t0610-reftable-basics.sh b/t/t0610-reftable-basics.sh
index 6a131e40b8..c5f4d23433 100755
--- a/t/t0610-reftable-basics.sh
+++ b/t/t0610-reftable-basics.sh
@@ -328,6 +328,19 @@ test_expect_success 'ref transaction: writes are synced' '
EOF
'
+test_expect_success 'ref transaction: empty transaction in empty repo' '
+ test_when_finished "rm -rf repo" &&
+ git init repo &&
+ test_commit -C repo --no-tag A &&
+ COMMIT=$(git -C repo rev-parse HEAD) &&
+ git -C repo update-ref -d refs/heads/main &&
+ test-tool -C repo ref-store main delete-refs REF_NO_DEREF msg HEAD &&
+ git -C repo update-ref --stdin <<-EOF
+ prepare
+ commit
+ EOF
+'
+
test_expect_success 'pack-refs: compacts tables' '
test_when_finished "rm -rf repo" &&
git init repo &&
--
2.44.0
Attachment:
signature.asc
Description: PGP signature
