Make PRESUBMIT.py run checks via 'pcg' if it is available in PATH.

PRESUBMIT.py

-# Copyright (c) 2015 The Chromium Authors. All rights reserved.
+# 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.
 
-"""Top-level presubmit script for client-go.
+"""Top-level presubmit script.
 
-See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
-details on the presubmit API built into gcl.
+See https://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
+details on the presubmit API built into depot_tools.
 """
 
+import os
+import sys
+
+
+def PreCommitGo(input_api, output_api, pcg_mode):
+  """Run go-specific checks via pre-commit-go (pcg) if it's in PATH."""
+  if input_api.is_committing:
+    error_type = output_api.PresubmitError
+  else:
+    error_type = output_api.PresubmitPromptWarning
+
+  exe = 'pcg.exe' if sys.platform == 'win32' else 'pcg'
+  pcg = None
+  for p in os.environ['PATH'].split(os.pathsep):
+    pcg = os.path.join(p, exe)
+    if os.access(pcg, os.X_OK):
+      break
+  else:
+    return [
+      error_type(
+        'pre-commit-go executable (pcg) could not be found in PATH. All Go '
+        'checks are skipped. See https://github.com/maruel/pre-commit-go.')
+    ]
+
+  # pcg can figure out what files to check on its own based on upstream ref.
+  cmd = [pcg, 'run', '-m', ','.join(pcg_mode)]
+  if input_api.verbose:
+    cmd.append('-v')
+  return input_api.RunTests([
+    input_api.Command(
+      name='pre-commit-go: %s' % ', '.join(pcg_mode),
+      cmd=cmd,
+      kwargs={},
+      message=error_type),
+  ])
+
+
+def header(input_api):
+  """Returns the expected license header regexp for this project."""
+  current_year = int(input_api.time.strftime('%Y'))
+  allowed_years = (str(s) for s in reversed(xrange(2011, current_year + 1)))
+  years_re = '(' + '|'.join(allowed_years) + ')'
+  license_header = (
+    r'.*? Copyright %(year)s The Chromium Authors\. '

[M-A Ruel, 2015/09/14 20:14:11]

I think we should standardize to LUCI Authors ASAP.

+    r'All rights reserved\.\n'
+    r'.*? Use of this source code is governed by a BSD-style license '
+    r'that can be\n'
+    r'.*? found in the LICENSE file\.(?: \*/)?\n'
+  ) % {
+    'year': years_re,
+  }
+  return license_header
+
+
+def source_file_filter(input_api):
+  """Returns filter that selects source code files only."""
+  bl = list(input_api.DEFAULT_BLACK_LIST) + [
+    r'.+\.pb\.go$',
+    r'.+_string\.go$',
+  ]
+  wl = list(input_api.DEFAULT_WHITE_LIST) + [
+    r'.+\.go$',
+  ]
+  return lambda x: input_api.FilterSourceFile(x, white_list=wl, black_list=bl)
+
 
 def CommonChecks(input_api, output_api):
-  return []
+  results = []
+  results.extend(
+    input_api.canned_checks.CheckChangeHasNoStrayWhitespace(
+      input_api, output_api,
+      source_file_filter=source_file_filter(input_api)))
+  results.extend(
+    input_api.canned_checks.CheckLicense(
+      input_api, output_api, header(input_api),
+      source_file_filter=source_file_filter(input_api)))
+  return results
 
 
 def CheckChangeOnUpload(input_api, output_api):
-  return CommonChecks(input_api, output_api)
+  results = CommonChecks(input_api, output_api)
+  results.extend(PreCommitGo(input_api, output_api, ['lint', 'pre-commit']))
+  return results
 
 
 def CheckChangeOnCommit(input_api, output_api):
-  return CommonChecks(input_api, output_api)
+  results = CommonChecks(input_api, output_api)
+  results.extend(input_api.canned_checks.CheckChangeHasDescription(
+      input_api, output_api))
+  results.extend(input_api.canned_checks.CheckDoNotSubmitInDescription(
+      input_api, output_api))
+  results.extend(input_api.canned_checks.CheckDoNotSubmitInFiles(
+      input_api, output_api))
+  results.extend(PreCommitGo(
+      input_api, output_api, ['lint', 'pre-commit', 'pre-push']))
+  return results