tree f6cdd39e80c2c5695a2fd37fd53aa2d63f803455
parent e6ad7080098a0db0cb304812c8603856da2bebf2
author Gavin Mak <gavinmak@google.com> 1787769779 +0000
committer gerrit-scoped@luci-project-accounts.iam.gserviceaccount.com <gerrit-scoped@luci-project-accounts.iam.gserviceaccount.com> 1787859780 -0700

project: don't use dest-branch or tags as SHA-1 upstream fallback

https://gerrit-review.googlesource.com/614762 resolves a fallback
upstream for a SHA-1-pinned project that has no explicit upstream, so
--current-branch can narrow the fetch to one branch instead of fetching
all heads.

It drew that fallback from dest-branch and from the manifest <default>
upstream, dest-branch, and revision. dest-branch and tags are not valid
fallback candidates:

* dest-branch is the review destination for upload, not a fetch
  source.
* Tags are meant to be immutable snapshots of a single tagged commit,
  and fetching it cannot retrieve an arbitrary pinned SHA-1.

Restrict the fallback to branch heads resolved from the manifest
upstream and revision defaults, and drop dest-branch entirely.

Bug: 541240657
Bug: 544041102
Change-Id: I89ae86891ee166f4c340553ac5a9068efcc18461
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/622541
Tested-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>
Reviewed-by: Brian Gan <brgan@google.com>