Handle case of deleted mojom file in Dart bindings presubmit script

mojo/dart/tools/presubmit/check_mojom_dart.py

 #!/usr/bin/env python
 # 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.
 
 """Checks that released mojom.dart files in the source tree are up to date"""
 
 import argparse
 import os
 import subprocess
@@ skipping 292 matching lines @@
 def presubmit_check(packages, affected_files):
   mojoms = filter_paths(affected_files, is_mojom)
   mojom_darts = filter_paths(affected_files, is_mojom_dart)
 
   if check_for_bindings_machinery_changes(affected_files):
     # Bindings machinery changed, perform global check instead.
     latest_mtime = bindings_machinery_latest_mtime(affected_files)
     return global_check(packages, latest_mtime)
 
   updated_mojom_dart_files = []
+  deleted_mojom_files = []
+  deleted_mojom_dart_files = []
   packages_with_failures = []
   check_failure = False
 
   # Check for updated .mojom without updated .mojom.dart
   for mojom_file in mojoms:
+    if not os.path.exists(mojom_file):
+      # File no longer exists. We cannot calculate the path of the associated
+      # .mojom.dart file, skip.
+      deleted_mojom_files.append(os.path.relpath(mojom_file, start=SRC_DIR))
+      continue
+
     try:
       mojom = _load_mojom(mojom_file)
     except Exception:
       # Could not load .mojom file
       print("Could not load mojom file: %s" % mojom_file)
       return True
 
     package = _mojom_package(mojom)
     # If a mojom doesn't have a package, ignore it.
     if not package:
       continue
     package_dir = packages.get(package)
     # If the package isn't a known package, ignore it.
     if not package_dir:
       continue
     # Expected output path relative to src.
     mojom_dart_path = os.path.relpath(
         os.path.join(package_dir, _mojom_output_path(mojom)), start=SRC_DIR)
 
     mojom_mtime = safe_mtime(mojom_file)
     mojom_dart_mtime = safe_mtime(os.path.join(SRC_DIR, mojom_dart_path))
 
     if mojom_mtime > mojom_dart_mtime:
       check_failure = True
-      print("Package %s has old %s" % (package, mojom_dart_path))
+      if mojom_dart_mtime == 0:
+        print("Package %s is missing %s" % (package, mojom_dart_path))
+      else:
+        print("Package %s has old %s" % (package, mojom_dart_path))
       if not (package in packages_with_failures):
         packages_with_failures.append(package)
       continue
+
     # Remember that this .mojom.dart file was updated after the .mojom file.
     # This list is used to verify that all updated .mojom.dart files were
     # updated because their source .mojom file changed.
     updated_mojom_dart_files.append(mojom_dart_path)
 
   # Check for updated .mojom.dart file without updated .mojom file.
   for mojom_dart_file in mojom_darts:
     # mojom_dart_file is not inside //mojo/dart/packages.
     if not mojom_dart_file.startswith(PACKAGES_DIR):
       continue
 
     # Path relative to //mojo/dart/packages/
     path_relative_to_packages = os.path.relpath(mojom_dart_file,
                                                 start=PACKAGES_DIR)
     # Package name is first element of split path.
     package = path_relative_to_packages.split(os.sep)[0]
     # Path relative to src.
     mojom_dart_path = os.path.relpath(mojom_dart_file, start=SRC_DIR)
+
     # If mojom_dart_path is not in updated_mojom_dart_files, a .mojom.dart
     # file was updated without updating the related .mojom file.
     if not (mojom_dart_path in updated_mojom_dart_files):
+      if not os.path.exists(mojom_dart_file):
+        deleted_mojom_dart_files.append(mojom_dart_path)
+        continue
       check_failure = True
       print("Package %s has new %s without updating source .mojom file." %
             (package, mojom_dart_path))
       if not (package in packages_with_failures):
         packages_with_failures.append(package)
 
+  # TODO(johnmccutchan): Fuzzy detection of a deleted .mojom file without a
+  # deleted .mojom.dart file.
+
   for package in packages_with_failures:
     _print_regenerate_message(package)
 
   return check_failure
 
 
 def main():
   parser = argparse.ArgumentParser(description='Generate a dart-pkg')
   parser.add_argument('--affected-files',
                       action='store',
@@ skipping 16 matching lines @@
   if args.affected_files:
     check_failure = presubmit_check(packages, args.affected_files)
   else:
     check_failure = global_check(packages)
   if check_failure:
     return 2
   return 0
 
 if __name__ == '__main__':
     sys.exit(main())