Add PRESUBMIT script to enforce WebAPK shell apk version update

chrome/android/webapk/shell_apk/PRESUBMIT.py

+# Copyright (c) 2017 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.
+
+"""Presubmit script for changes affecting chrome/android/webapk/shell_apk
+
+See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
+for more details about the presubmit API built into depot_tools.
+"""
+
+
+SRC_LOCAL_PATH = r'src/org/chromium/webapk/shell_apk'
+ANDROID_MANIFEST_LOCAL_PATH = r'AndroidManifest.xml'
+SHELL_APK_VERSION_LOCAL_PATH = r'shell_apk_version.gni'
+
+
+def _CommonChecks(input_api, output_api):
+  """Checks common to both upload and commit."""
+  # affected_files is list of files affected by this change. The paths are
+  # relative to the directory containing PRESUBMIT.py.
+  affected_files = [
+      input_api.os_path.relpath(f, input_api.PresubmitLocalPath())
+      for f in input_api.AbsoluteLocalPaths()
+  ]
+
+  problems = []
+
+  shell_apk_version_update_needed = False
+  shell_apk_version_is_updated = False
+  for f in affected_files:
+    if f.startswith(SRC_LOCAL_PATH):

[pkotwicz, 2017/04/21 20:17:30]

We should also check whether any files in res/ were updated as well

[F, 2017/04/26 19:59:24]

Done.

+      shell_apk_version_update_needed = True
+      problems.append(f)
+    elif f == ANDROID_MANIFEST_LOCAL_PATH:
+      shell_apk_version_update_needed = True
+      problems.append(f)
+    elif f == SHELL_APK_VERSION_LOCAL_PATH:
+      shell_apk_version_is_updated = True
+
+  if shell_apk_version_update_needed and not shell_apk_version_is_updated:
+    return [output_api.PresubmitPromptWarning(
+        '%s needs to be updated for shell APK version due to changes in:' %
+        SHELL_APK_VERSION_LOCAL_PATH, items=problems)]

[pkotwicz, 2017/04/21 20:17:30]

This is not quite right.

The correct sequence of events:
1) Changes in shell_apk/ are landed
2) ShellAPK is updated on WAM server (hartmanng@'s magical script)
3) CL is landed which modifies shell_apk_version.gni

It would be nice if hartmanng@'s magical script submits a Chromium CL which
increments the version

This means:
- We should have a presubmit check which ensures that if shell_apk_version.gni
is modified that it is the only file in the CL
- We should change the text in the presubmit to reflect that
shell_apk_version.gni needs to be changed in a follow up CL
  How about: "After this CL lands, you will need to 1) Update the WebAPK Minting
Server's version of the shell_apk/ code 2) Submit a CL which increments the
version in shell_apk_version.gni The version should be incremented *after*
updating the code on the WebAPK Minting Server"

[hartmanng, 2017/04/21 20:34:28]

We could change things around to make this work, but the server is not currently
able to handle that flow. On the official buildbots, we hardcode a shell version
number into the templated AndroidManifest.xml file based on what's in
shell_apk_version.gni. So if we don't update shell_apk_version.gni, the server
will think that nothing has updated. The only thing that the magical script does
on the server side is copy files verbatim from the buildbot's storage bucket
into the server's backend storage.

+
+  return []
+
+
+def CheckChangeOnUpload(input_api, output_api):
+  return _CommonChecks(input_api, output_api)
+
+
+def CheckChangeOnCommit(input_api, output_api):
+  return _CommonChecks(input_api, output_api)