tree 8ca77dd2aa718648a449107c0b264d4d7127288c
parent 0ea57e2eedbeae43e03c50b3aca4b890238d639f
author Rahul Yadav <yadavrah@google.com> 1788277532 +0000
committer gerrit-scoped@luci-project-accounts.iam.gserviceaccount.com <gerrit-scoped@luci-project-accounts.iam.gserviceaccount.com> 1788426923 -0700

project: check upstream ref ancestry for non-shallow clones

In _CheckForImmutableRevision, commit d9cc0a15 restricted upstream ref
validation strictly to superprojects (if use_superproject) to prevent
shallow clones with an upstream attribute from failing ancestry checks
and falling back to full clones.

However, restricting this check exclusively to superprojects broke
non-shallow projects with pinned immutable revisions (such as in Smart
Sync, `repo sync -t <BUILD_ID>`, or pinned manifests): When the target
commit already exists in the local Git object store (for instance,
prefetched into refs/prefetch/ by a background daemon or via shared
object dirs), _CheckForImmutableRevision returned True without verifying
that the local tracking ref (refs/remotes/<remote>/<upstream>) is
present and reaches the revision. As a result, _RemoteFetch skipped
fetching the upstream branch, leaving the local tracking ref stale or
missing. Subsequent `repo start` branches tracking that remote branch
diverged, causing `repo upload` to attempt uploading all intermediate
commits between the stale tracking ref and HEAD.

Restore upstream ancestry validation in _CheckForImmutableRevision for
non-shallow projects when upstream is specified. Also pass the sync
depth into _CheckForImmutableRevision call sites so shallow checkouts
continue to skip upstream verification and avoid triggering un-shallow
fallbacks.

Test: PYTHONPATH=. pytest tests/test_project.py
Change-Id: Ib5bdf41810bb06c8ed053447209ddc2e488f3913
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/624361
Tested-by: Rahul Yadav <yadavrah@google.com>
Commit-Queue: Rahul Yadav <yadavrah@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>