superproject: Skip updating of superproject when -l is used with sync.

Skip updating the superproject when -l is present and use the existing
superproject, if available (this would make sync -l work as it's
intended to do), and fall back to sync without superproject when not
(this would catch the case when superproject is enabled by automatic
rollout).

Tested:
$ repo sync -j 20 -n
NOTICE: --use-superproject is in beta; report any issues to the address described in `repo version`
/usr/local/google/home/rtenneti/work/android/src/aosp/.repo/exp-superproject/925043f706ba64db713e9bf3b55987e2-superproject.git: Initial setup for superproject completed.
Fetching: 100% (1032/1032), done in 41.184s
...

$ repo_dev sync -j 20 -l
prebuilts/asuite/: discarding 1 commits
prebuilts/runtime/: discarding 1 commits
...
repo sync has finished successfully.

+ With superproject-override.xml and test it.

  $ ls -l .repo/exp-superproject/
  total 176
  drwxr-xr-x 7 rtenneti primarygroup   4096 Jul 27 14:10 925043f706ba64db713e9bf3b55987e2-superproject.git
  -rw-r--r-- 1 rtenneti primarygroup 172742 Jul 27 14:10 superproject_override.xml
  rtenneti@rtenneti:~/work/android/src/aosp$ repo_dev sync -j 20 -l
  ...
  repo sync has finished successfully.

+ Rename the file superproject-override.xml and test it.
  $ ls -l .repo/exp-superproject/
  total 176
  drwxr-xr-x 7 rtenneti primarygroup   4096 Jul 27 14:10 925043f706ba64db713e9bf3b55987e2-superproject.git
  -rw-r--r-- 1 rtenneti primarygroup 172742 Jul 27 14:10 temp.xml

  $ repo_dev sync -j 20 -l
  Checking out:  1% (12/1031) platform/external/rust/crates/fallible-streaming-iteexternal/linux-kselftest/: discarding 1 commits
  prebuilts/remoteexecution-client/: discarding 1 commits
  Checking out: 51% (536/1031) platform/prebuilts/gcc/darwin-x86/aarch64/....
  ....
  Checking out: 100% (1031/1031), done in 5.478s
  repo sync has finished successfully.

Bug: [google internal] b/184368268
Change-Id: I3aba5872e4f7c299977b92c2a39847ef28698c5a
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/312962
Reviewed-by: Mike Frysinger <vapier@google.com>
Reviewed-by: Jonathan Nieder <jrn@google.com>
Tested-by: Raman Tenneti <rtenneti@google.com>

2 files changed, 11 insertions, 0 deletions

diff --git a/git_superproject.py b/git_superproject.py
index 86100960..8769355c 100644
--- a/git_superproject.py
+++ b/git_superproject.py
@@ -106,6 +106,11 @@ class Superproject(object):
     """Returns a dictionary of projects and their commit ids."""
     return self._project_commit_ids
 
+  @property
+  def manifest_path(self):
+    """Returns the manifest path if the path exists or None."""
+    return self._manifest_path if os.path.exists(self._manifest_path) else None
+
   def _GetBranch(self):
     """Returns the branch name for getting the approved manifest."""
     p = self._manifest.manifestProject
diff --git a/subcmds/sync.py b/subcmds/sync.py
index a770c253..74617544 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -301,6 +301,12 @@ later is required to fix a server side protocol bug.
                                                  self.repodir,
                                                  self.git_event_log,
                                                  quiet=opt.quiet)
+    if opt.local_only:
+      manifest_path = superproject.manifest_path
+      if manifest_path:
+        self._ReloadManifest(manifest_path, load_local_manifests)
+      return manifest_path
+
     all_projects = self.GetProjects(args,
                                     missing_ok=True,
                                     submodules_ok=opt.fetch_submodules)