setup the correct version of Xcode

scripts/slave/recipes/flutter/flutter.py

 # Copyright 2016 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 contextlib
 
 DEPS = [
   'depot_tools/git',
   'file',
   'gsutil',
+  'recipe_engine/json',
   'recipe_engine/path',
   'recipe_engine/platform',
   'recipe_engine/properties',
   'recipe_engine/step',
+  'recipe_engine/python',
 ]
 
 BUCKET_NAME = 'flutter_infra'
 
 
 def GetCloudPath(api, git_hash, path):
   return 'flutter/%s/%s' % (git_hash, path)
 
 
 def AnalyzeFlutter(api):
@@ skipping 95 matching lines @@
     if api.platform.is_linux:
       cloud_path = GetCloudPath(api, git_hash, 'examples/%s' % apk_name)
       api.gsutil.upload(app_path.join('build/app.apk'), BUCKET_NAME, cloud_path,
           link_name=apk_name, name='upload %s' % apk_name)
 
   # TODO(eseidel): We should not have to hard-code the desired apk name here.
   ArchiveAPK(api, 'examples/stocks', 'Stocks.apk')
   ArchiveAPK(api, 'examples/material_gallery', 'Gallery.apk')
 
 
+def RunFindXcode(api, step_name, target_version=None):
+  """Runs the `build/scripts/slave/ios/find_xcode.py` utility.
+
+     Retrieves information about xcode installations and to activate a specific
+     version of Xcode.
+  """
+  args = ['--json-file', api.json.output()]
+
+  if target_version is not None:
+    args.extend(['--version', target_version])
+
+  result = api.python(step_name, api.path['build'].join('scripts', 'slave',
+    'ios', 'find_xcode.py'), args)
+
+  return result.json.output
+
+
+def SetupXcode(api):
+  xcode_json = RunFindXcode(api, 'enumerate_xcode_installations')
+  installations = xcode_json["installations"]
+  activate_version = None
+  for key in installations:
+    version = installations[key].split()[0]
+    if version.startswith('7.'):
+      activate_version = version
+      break
+  if not activate_version:
+    raise api.step.StepFailure('Xcode version 7 or above not found')
+  RunFindXcode(api, 'set_xcode_version', target_version=activate_version)
+
+
 def RunSteps(api):
   # buildbot sets 'clobber' to the empty string which is falsey, check with 'in'
   if 'clobber' in api.properties:
     api.file.rmcontents('everything', api.path['slave_build'])
 
   git_hash = api.git.checkout(
       'https://chromium.googlesource.com/external/github.com/flutter/flutter',
       recursive=True, set_got_revision=True)
   checkout = api.path['checkout']
 
   api.step('download android tools',
       [checkout.join('infra', 'download_android_tools.py')])
 
   dart_bin = checkout.join('bin', 'cache', 'dart-sdk', 'bin')
   flutter_bin = checkout.join('bin')
   # TODO(eseidel): This is named exactly '.pub-cache' as a hack around
   # a regexp in flutter_tools analyze.dart which is in turn a hack around:
   # https://github.com/dart-lang/sdk/issues/25722
   pub_cache = api.path['slave_build'].join('.pub-cache')
   env = {
     'PATH': api.path.pathsep.join((str(flutter_bin), str(dart_bin),
         '%(PATH)s')),
     # Setup our own pub_cache to not affect other slaves on this machine.
     'PUB_CACHE': pub_cache,
     'ANDROID_HOME': checkout.join('infra', 'android_tools'),
   }
 
   # The context adds dart-sdk tools to PATH sets PUB_CACHE.
   with api.step.context({'env': env}):
+    if api.platform.is_mac:
+      SetupXcode(api)
+
     # Must be first to download dependencies for later steps.
     api.step('flutter doctor', ['flutter', 'doctor'])
     api.step('update packages', ['flutter', 'update-packages'])
     AnalyzeFlutter(api)
     TestFlutterPackagesAndExamples(api)
     BuildExamples(api, git_hash)
 
     # TODO(yjbanov): we do not yet have Android devices hooked up, nor do we
     # support the Android emulator. For now, only run on iOS Simulator.
     if api.platform.is_mac:
       TestCreateAndLaunch(api)
 
     # TODO(eseidel): We only want to generate one copy of the docs at a time
     # otherwise multiple rsyncs could race, causing badness. We'll eventually
     # need both a lock on the bucket, as well as some assurance that we're
     # always moving the docs forward. Possibly by using a separate builder.
     # Until then, only generate on linux to reduce the chance of race.
     if api.platform.is_linux:
       # TODO(eseidel): Is there a way for GenerateDocs to read PUB_CACHE from
       # the env instead of me passing it in?
       GenerateDocs(api, pub_cache)
 
 
 def GenTests(api):
   for platform in ('mac', 'linux'):
-    yield (api.test(platform) + api.platform(platform, 64) +
+    test = (api.test(platform) + api.platform(platform, 64) +
         api.properties(clobber=''))
+
+    if platform == 'mac':
+      test += (
+        api.step_data('enumerate_xcode_installations', api.json.output({
+          'installations': {
+            '/some/path': '7.2.1 build_number'
+          }
+        })) +
+        api.step_data('set_xcode_version', api.json.output({}))
+      )
+
+    yield test
+
+  yield (
+    api.test('mac_cannot_find_xcode') +
+    api.platform('mac', 64) +
+    api.properties(clobber='') +
+    api.step_data('enumerate_xcode_installations', api.json.output({
+      'installations': {}
+    }))
+  )