Move git revision fetching

Author: zanderso

.gitignore

@@ -142,3 +142,8 @@ app.*.symbols
 
 # The gn-sdk from Chromium and managed by DEPS and gclient.
 /tools/fuchsia/gn-sdk
+
+# Git revision files created by gclient runhooks
+engine.revision
+dart.revision
+skia.revision

DEPS

@@ -1236,5 +1236,41 @@ hooks = [
       '--as-gclient-hook',
       Var('mac_sdk_min')
     ]
+  },
+  {
+    'name': 'Get Engine git revision',
+    'pattern': '.',
+    'action': [
+      'python3',
+      'src/flutter/build/git_revision.py',
+      '--repository',
+      'src/flutter',
+      '--output',
+      'src/flutter/engine.revision',
+    ]
+  },
+  {
+    'name': 'Get Skia git revision',
+    'pattern': '.',
+    'action': [
+      'python3',
+      'src/flutter/build/git_revision.py',
+      '--repository',
+      'src/flutter/third_party/skia',
+      '--output',
+      'src/flutter/skia.revision',
+    ]
+  },
+  {
+    'name': 'Get Dart git revision',
+    'pattern': '.',
+    'action': [
+      'python3',
+      'src/flutter/build/git_revision.py',
+      '--repository',
+      'src/third_party/dart',
+      '--output',
+      'src/flutter/dart.revision',
+    ]
   }
 ]

build/git_revision.py

@@ -42,10 +42,18 @@ def main():
   parser.add_argument(
       '--repository', action='store', help='Path to the Git repository.', required=True
   )
+  parser.add_argument(
+      '--output', action='store', help='Write revision to a file at this path instead of printing.'
+  )
 
   args = parser.parse_args()
   repository = os.path.abspath(args.repository)
   version = get_repository_version(repository)
+
+  if args.output:
+    with open(args.output, 'w') as file:
+      file.write(version.strip())
+
   print(version.strip())
 
   return 0

tools/gn

@@ -344,6 +344,24 @@ def setup_apple_sdks():
   return sdks_gn_args
 
 
+def setup_git_versions():
+  revision_args = {}
+
+  engine_version_file = os.path.join(SRC_ROOT, 'flutter', 'engine.revision')
+  with open(engine_version_file, encoding='utf-8') as file:
+    revision_args['engine_version'] = file.read().strip()
+
+  skia_version_file = os.path.join(SRC_ROOT, 'flutter', 'skia.revision')
+  with open(skia_version_file, encoding='utf-8') as file:
+    revision_args['skia_version'] = file.read().strip()
+
+  dart_version_file = os.path.join(SRC_ROOT, 'flutter', 'dart.revision')
+  with open(dart_version_file, encoding='utf-8') as file:
+    revision_args['dart_version'] = file.read().strip()
+
+  return revision_args
+
+
 def to_gn_args(args):
   if args.simulator:
     if args.target_os != 'ios':
@@ -355,6 +373,8 @@ def to_gn_args(args):
 
   gn_args['is_debug'] = args.unoptimized
 
+  gn_args.update(setup_git_versions())
+
   gn_args.update(setup_goma(args))
 
   gn_args.update(setup_rbe(args))

tools/licenses/lib/paths.dart

@@ -22,12 +22,15 @@ final Set<String> skippedPaths = <String>{
   r'buildtools', // only used by build
   r'flutter/build',
   r'flutter/ci',
+  r'flutter/dart.revision', // only used by build
   r'flutter/docs',
+  r'flutter/engine.revision', // only used by build
   r'flutter/flutter_frontend_server',
   r'flutter/impeller/docs',
   r'flutter/lib/web_ui/build', // this is compiler-generated output
   r'flutter/lib/web_ui/dev', // these are build tools; they do not end up in Engine artifacts
   r'flutter/prebuilts',
+  r'flutter/skia.revision', // only used by build
   r'flutter/sky/packages/sky_engine/LICENSE',
   r'flutter/third_party/benchmark', // only used by tests
   r'flutter/third_party/boringssl/src/crypto/err/err_data_generate.go',