sync: Share self-update logic between sync modes

The logic for checking for repo self-updates lives in _FetchMain, which
is part of the "phased" sync path.

Extract this logic into a new _UpdateRepoProject helper method. Call
this common helper from _ExecuteHelper before either sync mode begins,
so the repo self-update check is always performed.

Bug: 421935613
Change-Id: I9a804f43fbf6239c4146be446040be531f12fc8a
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/484041
Reviewed-by: Scott Lee <ddoman@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>
Tested-by: Gavin Mak <gavinmak@google.com>

subcmds/sync.py

@@ -989,26 +989,16 @@ later is required to fix a server side protocol bug.
         Returns:
             List of all projects that should be checked out.
         """
-        rp = manifest.repoProject
-
         to_fetch = []
-        now = time.time()
-        if _ONE_DAY_S <= (now - rp.LastFetch):
-            to_fetch.append(rp)
         to_fetch.extend(all_projects)
         to_fetch.sort(key=self._fetch_times.Get, reverse=True)
 
         result = self._Fetch(to_fetch, opt, err_event, ssh_proxy, errors)
         success = result.success
         fetched = result.projects
-
         if not success:
             err_event.set()
 
-        # Call self update, unless requested not to
-        # TODO(b/42193561): Extract repo update logic to ExecuteHelper.
-        if os.environ.get("REPO_SKIP_SELF_UPDATE", "0") == "0":
-            _PostRepoFetch(rp, opt.repo_verify)
         if opt.network_only:
             # Bail out now; the rest touches the working tree.
             if err_event.is_set():
@@ -1369,6 +1359,61 @@ later is required to fix a server side protocol bug.
             t.join()
         pm.end()
 
+    def _UpdateRepoProject(self, opt, manifest, errors):
+        """Fetch the repo project and check for updates."""
+        if opt.local_only:
+            return
+
+        rp = manifest.repoProject
+        now = time.time()
+        # If we've fetched in the last day, don't bother fetching again.
+        if (now - rp.LastFetch) < _ONE_DAY_S:
+            return
+
+        with multiprocessing.Manager() as manager:
+            with ssh.ProxyManager(manager) as ssh_proxy:
+                ssh_proxy.sock()
+                start = time.time()
+                buf = TeeStringIO(sys.stdout if opt.verbose else None)
+                sync_result = rp.Sync_NetworkHalf(
+                    quiet=opt.quiet,
+                    verbose=opt.verbose,
+                    output_redir=buf,
+                    current_branch_only=self._GetCurrentBranchOnly(
+                        opt, manifest
+                    ),
+                    force_sync=opt.force_sync,
+                    clone_bundle=opt.clone_bundle,
+                    tags=opt.tags,
+                    archive=manifest.IsArchive,
+                    optimized_fetch=opt.optimized_fetch,
+                    retry_fetches=opt.retry_fetches,
+                    prune=opt.prune,
+                    ssh_proxy=ssh_proxy,
+                    clone_filter=manifest.CloneFilter,
+                    partial_clone_exclude=manifest.PartialCloneExclude,
+                    clone_filter_for_depth=manifest.CloneFilterForDepth,
+                )
+                if sync_result.error:
+                    errors.append(sync_result.error)
+
+                finish = time.time()
+                self.event_log.AddSync(
+                    rp,
+                    event_log.TASK_SYNC_NETWORK,
+                    start,
+                    finish,
+                    sync_result.success,
+                )
+                if not sync_result.success:
+                    logger.error("error: Cannot fetch repo tool %s", rp.name)
+                    return
+
+        # After fetching, check if a new version of repo is available and
+        # restart. This is only done if the user hasn't explicitly disabled it.
+        if os.environ.get("REPO_SKIP_SELF_UPDATE", "0") == "0":
+            _PostRepoFetch(rp, opt.repo_verify)
+
     def _ReloadManifest(self, manifest_name, manifest):
         """Reload the manfiest from the file specified by the |manifest_name|.
 
@@ -1871,6 +1916,9 @@ later is required to fix a server side protocol bug.
         # might be in the manifest.
         self._ValidateOptionsWithManifest(opt, mp)
 
+        # Update the repo project and check for new versions of repo.
+        self._UpdateRepoProject(opt, manifest, errors)
+
         superproject_logging_data = {}
         self._UpdateProjectsRevisionId(
             opt, args, superproject_logging_data, manifest