Add checkdeps presubmit check. Warns on new #includes of dependencies

PRESUBMIT.py

Index: PRESUBMIT.py
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 8954faedd6d18cd25d80ff94c40da06c75a787d6..05fd28b2cc1ea9b9a981bb69102e9f394c5e3134 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -10,6 +10,7 @@ for more details about the presubmit API built into gcl.
 
 
 import re
+import sys
 
 
 _EXCLUDED_PATHS = (
@@ -374,6 +375,59 @@ def _CheckNoPragmaOnce(input_api, output_api):
   return []
 
 
+def _CheckUnwantedDependencies(input_api, output_api):
+  """Runs checkdeps on #include statements added in this
+  change. Breaking - rules is an error, breaking ! rules is a
+  warning.
+  """
+  # We need to wait until we have an input_api object and use this
+  # roundabout construct to import checkdeps because this file is
+  # eval-ed and thus doesn't have __file__.
+  original_sys_path = sys.path
+  try:
+    sys.path = sys.path + [input_api.os_path.join(
+        input_api.PresubmitLocalPath(), 'tools', 'checkdeps')]
+    import checkdeps
+    from cpp_checker import CppChecker
+    from rules import Rule
+  finally:
+    # Restore sys.path to what it was before.
+    sys.path = original_sys_path
+
+  added_includes = []
+  for f in input_api.AffectedFiles():
+    if not CppChecker.IsCppFile(f.LocalPath()):
+      continue
+
+    changed_lines = [line for line_num, line in f.ChangedContents()]
+    added_includes.append([f.LocalPath(), changed_lines])
+
+  deps_checker = checkdeps.DepsChecker()
+
+  error_descriptions = []
+  warning_descriptions = []
+  for path, rule_type, rule_description in deps_checker.CheckAddedCppIncludes(
+      added_includes):
+    description_with_path = '%s\n    %s' % (path, rule_description)
+    if rule_type == Rule.DISALLOW:
+      error_descriptions.append(description_with_path)
+    else:
+      warning_descriptions.append(description_with_path)
+
+  results = []
+  if error_descriptions:
+    results.append(output_api.PresubmitError(
+        'You added one or more #includes that violate checkdeps rules.',
+        error_descriptions))
+  if warning_descriptions:
+    results.append(output_api.PresubmitPromptWarning(
+        'You added one or more #includes of files that are temporarily\n'
+        'allowed but being removed. Can you avoid introducing the\n'
+        '#include? See relevant DEPS file(s) for details and contacts.',
+        warning_descriptions))
+  return results
+
+
 def _CommonChecks(input_api, output_api):
   """Checks common to both upload and commit."""
   results = []
@@ -388,6 +442,7 @@ def _CommonChecks(input_api, output_api):
   results.extend(_CheckNoDEPSGIT(input_api, output_api))
   results.extend(_CheckNoBannedFunctions(input_api, output_api))
   results.extend(_CheckNoPragmaOnce(input_api, output_api))
+  results.extend(_CheckUnwantedDependencies(input_api, output_api))
   return results