Add post upload Python 3 option

Adds --no-python2-post-upload-hooks to git_cl.py. This causes any
post upload hooks to only run under Python 3. Without this, uploading
CLs from builders that omit Python 2 causes the CL the step to fail
after the CL is uploaded.

Bug: 1340617
Change-Id: I5fb45922fb05b28ad570091f9e285dd533d92336
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3996467
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Joanna Wang <jojwang@chromium.org>
Reviewed-by: Joanna Wang <jojwang@chromium.org>

git_cl.py

@@ -1455,17 +1455,19 @@ class Changelist(object):
             py2_results.get('warnings', []) + py3_results.get('warnings', []))
     }
 
-  def RunPostUploadHook(self, verbose, upstream, description):
+  def RunPostUploadHook(self, verbose, upstream, description, py3_only):
     args = self._GetCommonPresubmitArgs(verbose, upstream)
     args.append('--post_upload')
 
     with gclient_utils.temporary_file() as description_file:
       gclient_utils.FileWrite(description_file, description)
       args.extend(['--description_file', description_file])
-      p_py2 = subprocess2.Popen(['vpython', PRESUBMIT_SUPPORT] + args)
+      if not py3_only:
+        p_py2 = subprocess2.Popen(['vpython', PRESUBMIT_SUPPORT] + args)
       p_py3 = subprocess2.Popen(['vpython3', PRESUBMIT_SUPPORT] + args +
                                 ['--use-python3'])
-      p_py2.wait()
+      if not py3_only:
+        p_py2.wait()
       p_py3.wait()
 
   def _GetDescriptionForUpload(self, options, git_diff_args, files):
@@ -1599,8 +1601,9 @@ class Changelist(object):
           'last-upload-hash', scm.GIT.ResolveCommit(settings.GetRoot(), 'HEAD'))
       # Run post upload hooks, if specified.
       if settings.GetRunPostUploadHook():
-        self.RunPostUploadHook(
-            options.verbose, base_branch, change_desc.description)
+        self.RunPostUploadHook(options.verbose, base_branch,
+                               change_desc.description,
+                               options.no_python2_post_upload_hooks)
 
       # Upload all dependencies if specified.
       if options.dependencies:
@@ -4402,6 +4405,9 @@ def CMDupload(parser, args):
                     action='store_true',
                     dest='no_add_changeid',
                     help='Do not add change-ids to messages.')
+  parser.add_option('--no-python2-post-upload-hooks',
+                    action='store_true',
+                    help='Only run post-upload hooks in Python 3.')
 
   orig_args = args
   (options, args) = parser.parse_args(args)

tests/git_cl_test.py

@@ -3315,7 +3315,7 @@ class ChangelistTest(unittest.TestCase):
 
   def testRunPostUploadHook(self):
     cl = git_cl.Changelist()
-    cl.RunPostUploadHook(2, 'upstream', 'description')
+    cl.RunPostUploadHook(2, 'upstream', 'description', False)
 
     subprocess2.Popen.assert_any_call([
         'vpython',
@@ -3372,6 +3372,40 @@ class ChangelistTest(unittest.TestCase):
     gclient_utils.FileWrite.assert_called_once_with(
         '/tmp/fake-temp1', 'description')
 
+  def testRunPostUploadHookPy3Only(self):
+    cl = git_cl.Changelist()
+    cl.RunPostUploadHook(2, 'upstream', 'description', True)
+
+    subprocess2.Popen.assert_called_once_with([
+        'vpython3',
+        'PRESUBMIT_SUPPORT',
+        '--root',
+        'root',
+        '--upstream',
+        'upstream',
+        '--verbose',
+        '--verbose',
+        '--gerrit_url',
+        'https://chromium-review.googlesource.com',
+        '--gerrit_project',
+        'project',
+        '--gerrit_branch',
+        'refs/heads/main',
+        '--author',
+        'author',
+        '--issue',
+        '123456',
+        '--patchset',
+        '7',
+        '--post_upload',
+        '--description_file',
+        '/tmp/fake-temp1',
+        '--use-python3',
+    ])
+
+    gclient_utils.FileWrite.assert_called_once_with('/tmp/fake-temp1',
+                                                    'description')
+
   @mock.patch('git_cl.RunGit', _mock_run_git)
   def testDefaultTitleEmptyMessage(self):
     cl = git_cl.Changelist()