git: fix git cache support

recipe_modules/git/api.py

 # Copyright 2013 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.
 
 import itertools
 import re
 
 from recipe_engine import recipe_api
 
 class GitApi(recipe_api.RecipeApi):
@@ skipping 195 matching lines @@
     self.m.python(
         'git setup%s' % step_suffix,
         self.resource('git_setup.py'),
         git_setup_args)
 
     # Some of the commands below require depot_tools to be in PATH.
     path = self.m.path.pathsep.join([
         str(self.package_repo_resource()), '%(PATH)s'])
 
     if use_git_cache:
-      self('retry', 'cache', 'fetch', '-c', self.m.path['git_cache'],
-           cwd=dir_path,
-           name='fetch cache',
-           can_fail_build=can_fail_build,
-           env={'PATH': path})
+      with self.m.step.context({'env': {'PATH': path}}):
+        self('retry', 'cache', 'populate', '-c', self.m.path['git_cache'], url,
+             name='populate cache',
+             can_fail_build=can_fail_build,
+             cwd=dir_path)
+        dir_cmd = self(
+            'cache', 'exists', '--quiet',
+            '--cache-dir', self.m.path['git_cache'], url,
+            can_fail_build=can_fail_build,
+            stdout=self.m.raw_io.output(),
+            step_test_data=lambda:
+                self.m.raw_io.test_api.stream_output('mirror_dir'),
+            cwd=dir_path)
+        mirror_dir = dir_cmd.stdout.strip()
+        self('remote', 'set-url', 'origin', mirror_dir,
+             can_fail_build=can_fail_build,
+             cwd=dir_path)
 
     # There are five kinds of refs we can be handed:
     # 0) None. In this case, we default to properties['branch'].
     # 1) A 40-character SHA1 hash.
     # 2) A fully-qualifed arbitrary ref, e.g. 'refs/foo/bar/baz'.
     # 3) A fully qualified branch name, e.g. 'refs/heads/master'.
     #    Chop off 'refs/heads' and now it matches case (4).
     # 4) A branch name, e.g. 'master'.
     # Note that 'FETCH_HEAD' can be many things (and therefore not a valid
     # checkout target) if many refs are fetched, but we only explicitly fetch
@@ skipping 158 matching lines @@
 
     Args:
       bundle_path (Path): The path of the output bundle.
       refs (list): The list of refs to include in the bundle. If None, all
           refs in the Git checkout will be bundled.
       kwargs: Forwarded to '__call__'.
     """
     if not rev_list_args:
       rev_list_args = ['--all']
     self('bundle', 'create', bundle_path, *rev_list_args, **kwargs)