git cl: safe fallback for Gerrit RPCs even if gerrit project is unknown.

R=ehmaldonado

Bug: 876910
Change-Id: I258efa0a95f20b80819bc89cccfb5e0a29e09d5c
Reviewed-on: https://chromium-review.googlesource.com/1188989
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>

git_cl.py

@@ -2405,10 +2405,12 @@ class _GerritChangelistImpl(_ChangelistCodereviewBase):
         self._gerrit_server = 'https://%s' % self._gerrit_host
     return self._gerrit_server
 
-  def _GetGerritProject(self, remote_url=None):
+  def _GetGerritProject(self):
     """Returns Gerrit project name based on remote git URL."""
+    remote_url = self.GetRemoteUrl()
     if remote_url is None:
-      remote_url = self.GetRemoteUrl()
+      logging.warn('can\'t detect Gerrit project.')
+      return None
     project = urlparse.urlparse(remote_url).path.strip('/')
     if project.endswith('.git'):
       project = project[:-len('.git')]
@@ -2426,9 +2428,13 @@ class _GerritChangelistImpl(_ChangelistCodereviewBase):
     """Handy method for gerrit_util.ChangeIdentifier for a given CL.
 
     Not to be confused by value of "Change-Id:" footer.
+    If Gerrit project can be determined, this will speed up Gerrit HTTP API RPC.
     """
-    return gerrit_util.ChangeIdentifier(
-        self._GetGerritProject(), self.GetIssue())
+    project = self._GetGerritProject()
+    if project:
+      return gerrit_util.ChangeIdentifier(project, self.GetIssue())
+    # Fall back on still unique, but less efficient change number.
+    return str(self.GetIssue())
 
   @classmethod
   def IssueConfigKey(cls):

tests/git_cl_test.py

@@ -3450,7 +3450,7 @@ class TestGitCl(TestCase):
     self.assertEqual(cl.GetRemoteUrl(), url)
     self.assertEqual(cl.GetRemoteUrl(), url)  # Must be cached.
 
-  def test_gerrit_project_detection(self):
+  def test_gerrit_change_identifier_with_project(self):
     self.calls = [
       ((['git', 'symbolic-ref', 'HEAD'],), 'master'),
       ((['git', 'config', 'branch.master.merge'],), 'master'),
@@ -3458,8 +3458,18 @@ class TestGitCl(TestCase):
       ((['git', 'config', 'remote.origin.url'],),
        'https://chromium.googlesource.com/a/my/repo.git/'),
     ]
-    cl = git_cl.Changelist(codereview='gerrit', issue=1)
-    self.assertEqual(cl._GetGerritProject(), 'my/repo')
+    cl = git_cl.Changelist(codereview='gerrit', issue=123456)
+    self.assertEqual(cl._GerritChangeIdentifier(), 'my%2Frepo~123456')
+
+  def test_gerrit_change_identifier_without_project(self):
+    self.calls = [
+      ((['git', 'symbolic-ref', 'HEAD'],), 'master'),
+      ((['git', 'config', 'branch.master.merge'],), 'master'),
+      ((['git', 'config', 'branch.master.remote'],), 'origin'),
+      ((['git', 'config', 'remote.origin.url'],), CERR1),
+    ]
+    cl = git_cl.Changelist(codereview='gerrit', issue=123456)
+    self.assertEqual(cl._GerritChangeIdentifier(), '123456')
 
 
 if __name__ == '__main__':