drover win: Use --stdin so update-index doesn't fail on long cmdline

tests/git_drover_test.py

 #!/usr/bin/env python
 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """Tests for git_drover."""
 
 import os
 import shutil
 import subprocess
 import sys
@@ skipping 19 matching lines @@
     with open(os.path.join(self._parent_repo, '.git', 'HEAD'), 'w') as f:
       f.write('HEAD')
     os.mkdir(os.path.join(self._parent_repo, '.git', 'info'))
     with open(
         os.path.join(self._parent_repo, '.git', 'info', 'refs'), 'w') as f:
       f.write('refs')
     self.mock(tempfile, 'mkdtemp', self._mkdtemp)
     self.mock(__builtins__, 'raw_input', self._get_input)
     self.mock(subprocess, 'check_call', self._check_call)
     self.mock(subprocess, 'check_output', self._check_call)
+    self.real_popen = subprocess.Popen
+    self.mock(subprocess, 'Popen', self._Popen)
     self._commands = []
     self._input = []
     self._fail_on_command = None
 
     self.REPO_CHECK_COMMANDS = [
         (['git', '--help'], self._parent_repo),
         (['git', 'status'], self._parent_repo),
         (['git', 'fetch', 'origin'], self._parent_repo),
         (['git', 'rev-parse', 'refs/remotes/branch-heads/branch^{commit}'],
          self._parent_repo),
@@ skipping 18 matching lines @@
       self.BRANCH_CLEANUP_COMMANDS = [
           (['rmdir', '/s', '/q', self._target_repo], None),
           (['git', 'branch', '-D', 'drover_branch_123'], self._parent_repo),
       ]
     else:
       self.BRANCH_CLEANUP_COMMANDS = [
           (['git', 'branch', '-D', 'drover_branch_123'], self._parent_repo),
       ]
     self.MANUAL_RESOLVE_PREPARATION_COMMANDS = [
         (['git', 'status', '--porcelain'], self._target_repo),
-        (['git', 'update-index', '--skip-worktree', '--', 'foo', 'bar'],
+        (['git', 'update-index', '--skip-worktree', '--stdin'],
          self._target_repo),
     ]
     self.FINISH_MANUAL_RESOLVE_COMMANDS = [
         (['git', 'commit', '--no-edit'], self._target_repo),
     ]
 
   def tearDown(self):
     shutil.rmtree(self._temp_directory)
     super(GitDroverTest, self).tearDown()
 
@@ skipping 17 matching lines @@
     if (self._fail_on_command is not None and
         self._fail_on_command == len(self._commands)):
       self._fail_on_command = None
       raise subprocess.CalledProcessError(1, args[0])
     if args == ['git', 'rev-parse', '--git-dir']:
       return os.path.join(self._parent_repo, '.git')
     if args == ['git', 'status', '--porcelain']:
       return ' D foo\nUU baz\n D bar\n'
     return ''
 
+  def _Popen(self, args, shell=False, cwd=None, stdin=None, stdout=None,
+             stderr=None):
+    if args == ['git', 'update-index', '--skip-worktree', '--stdin']:
+      self._commands.append((args, cwd))
+      self.assertFalse(shell)
+      self.assertEqual(stdin, subprocess.PIPE)
+      class MockPopen(object):
+        def __init__(self, *args, **kwargs):
+          self.returncode = -999
+        def communicate(self, stdin):
+          if stdin == 'foo\nbar\n':
+            self.returncode = 0
+          else:
+            self.returncode = 1
+      return MockPopen()
+    else:
+      return self.real_popen(args, shell=shell, cwd=cwd, stdin=stdin,
+                             stdout=stdout, stderr=stderr)
+
   def testSuccess(self):
     self._input = ['y', 'y']
     git_drover.cherry_pick_change('branch', 'cl', self._parent_repo, False)
     self.assertEqual(
         self.REPO_CHECK_COMMANDS + self.LOCAL_REPO_COMMANDS +
         self.UPLOAD_COMMANDS + self.LAND_COMMAND + self.BRANCH_CLEANUP_COMMANDS,
         self._commands)
     self.assertFalse(os.path.exists(self._target_repo))
     self.assertFalse(self._input)
 
@@ skipping 166 matching lines @@
     self.assertRaises(git_drover.Error, git_drover.continue_cherry_pick,
                       self._parent_repo)
 
   def testAbortInvalidWorkdir(self):
     self.assertRaises(git_drover.Error, git_drover.abort_cherry_pick,
                       self._parent_repo)
 
 
 if __name__ == '__main__':
   unittest.main()