lint: Require python3 shebangs.

This commit was originally from @fredfishgames, but it
needed a big rebase due to use letting it sit too long.
Also, we decided not to have shebangs at the top of test
files.

tools/custom_check.py

@@ -166,7 +166,11 @@ def build_custom_checkers(by_lang):
         # and comments which should be rewritten to avoid use of "python2", "python3", etc.
         {'pattern': 'python[23]',
          'exclude': set(['tools/provision']),
+         'include_only': set(['zulip/', 'tools/', 'zulip_botserver/']),
          'description': 'Explicit python invocations should not include a version'},
+        {'pattern': '#!/usr/bin/env python$',
+         'include_only': set(['zulip_bots/']),
+         'description': 'Python shebangs must be python3'},
         {'pattern': '(^|\s)open\s*\(',
          'description': 'open() should not be used in Zulip\'s bots. Use functions'
                         ' provided by the bots framework to access the filesystem.',

zulip_bots/generate_manifest.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import argparse
 import os

zulip_bots/setup.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 from __future__ import print_function

zulip_bots/zulip_bots/bots/chess/test_chess.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase
 
 class TestChessBot(StubBotTestCase):

zulip_bots/zulip_bots/bots/converter/test_converter.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase
 
 class TestConverterBot(StubBotTestCase):

zulip_bots/zulip_bots/bots/define/test_define.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase
 from unittest.mock import patch
 

zulip_bots/zulip_bots/bots/dialogflow/test_dialogflow.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase, read_bot_fixture_data
 
 from contextlib import contextmanager

zulip_bots/zulip_bots/bots/encrypt/test_encrypt.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase
 
 class TestEncryptBot(StubBotTestCase):

zulip_bots/zulip_bots/bots/followup/test_followup.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from __future__ import absolute_import
 from __future__ import print_function
 

zulip_bots/zulip_bots/bots/giphy/test_giphy.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from unittest.mock import patch
 from requests.exceptions import HTTPError, ConnectionError
 

zulip_bots/zulip_bots/bots/github_detail/test_github_detail.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import (
     StubBotHandler,
     StubBotTestCase,

zulip_bots/zulip_bots/bots/google_search/test_google_search.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase
 
 from unittest.mock import patch

zulip_bots/zulip_bots/bots/helloworld/test_helloworld.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase
 
 class TestHelpBot(StubBotTestCase):

zulip_bots/zulip_bots/bots/help/test_help.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase
 
 from typing import Any

zulip_bots/zulip_bots/bots/incrementor/test_incrementor.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 import mock
 
 from zulip_bots.test_lib import (

zulip_bots/zulip_bots/bots/tictactoe/test_tictactoe.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 from zulip_bots.test_lib import StubBotTestCase
 
 class TestTictactoeBot(StubBotTestCase):

zulip_bots/zulip_bots/bots/wikipedia/test_wikipedia.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from zulip_bots.test_lib import StubBotTestCase
 from zulip_bots.request_test_lib import mock_request_exception
 

zulip_bots/zulip_bots/bots/xkcd/test_xkcd.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 import mock
 from mock import MagicMock, patch
 from zulip_bots.test_lib import StubBotTestCase

zulip_bots/zulip_bots/bots/youtube/test_youtube.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from __future__ import absolute_import
 
 from unittest.mock import patch

zulip_bots/zulip_bots/provision.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 from __future__ import absolute_import
 

zulip_bots/zulip_bots/run.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 from __future__ import print_function
 from __future__ import absolute_import
 

zulip_bots/zulip_bots/terminal.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 import os
 import sys
 import argparse

zulip_bots/zulip_bots/test_run.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 from __future__ import absolute_import
 
 import importlib