project: run fetch --refetch onacould not parse commit

git may gc reachable objects in partial clone repository due to a bug
(report:
https://lore.kernel.org/git/20240802073143.56731-1-hanyang.tony@bytedance.com/
). Until git is properly patched and released, force --refetch iff
"could not parse commit" is part of git output. --refetch will will
ensure that gc'ed objects are retrieved.

Bug: b/360889369
Change-Id: I0fc911c591060f859235dcd8d019881106f0858e
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/437017
Commit-Queue: Josip Sokcevic <sokcevic@google.com>
Reviewed-by: Sam Saccone <samccone@google.com>
Tested-by: Josip Sokcevic <sokcevic@google.com>

project.py

@@ -2659,6 +2659,17 @@ class Project:
                 # Fallthru to sleep+retry logic at the bottom.
                 pass
 
+            # TODO(b/360889369#comment24): git may gc commits incorrectly.
+            # Until the root cause is fixed, retry fetch with --refetch which
+            # will bring the repository into a good state.
+            elif gitcmd.stdout and "could not parse commit" in gitcmd.stdout:
+                cmd.insert(1, "--refetch")
+                print(
+                    "could not parse commit error, retrying with refetch",
+                    file=output_redir,
+                )
+                continue
+
             # Try to prune remote branches once in case there are conflicts.
             # For example, if the remote had refs/heads/upstream, but deleted
             # that and now has refs/heads/upstream/foo.