Add presubmit check for package_config.json .

Change-Id: Ida784b6e73601e0309e10b2808f46e70926eabc0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/183045
Commit-Queue: Leaf Petersen <leafp@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>
Reviewed-by: Bob Nystrom <rnystrom@google.com>

PRESUBMIT.py

@@ -213,6 +213,34 @@ def _CheckStatusFiles(input_api, output_api):
     return []
 
 
+def _CheckPackageConfigUpToDate(input_api, output_api):
+    """Checks that .dart_tool/package_config.json is up to date."""
+    # Run only if DEPS file or package_config.json have been modified.
+    if not any(p == 'DEPS' or p == '.dart_tool/package_config.json' or
+               p.endswith('pubspec.yaml') for p in input_api.LocalPaths()):
+        return []
+    local_root = input_api.change.RepositoryRoot()
+    utils = imp.load_source('utils',
+                            os.path.join(local_root, 'tools', 'utils.py'))
+
+    dart = utils.CheckedInSdkExecutable()
+    generate = os.path.join(local_root, 'tools', 'generate_package_config.dart')
+    cmd = [dart, generate, '--check']
+    pipe = subprocess.Popen(cmd,
+                            stdout=subprocess.PIPE,
+                            stderr=subprocess.PIPE,
+                            shell=utils.IsWindows())
+    output = pipe.communicate()
+    if pipe.returncode != 0:
+        return [
+            output_api.PresubmitError(
+                'File .dart_tool/package_config.json is out of date.\n'
+                'Fix these issues with:\n'
+                '%s tools/generate_package_config.dart' % (dart))
+        ]
+    return []
+
+
 def _CheckValidHostsInDEPS(input_api, output_api):
     """Checks that DEPS file deps are from allowed_hosts."""
     # Run only if DEPS file has been modified to annoy fewer bystanders.
@@ -333,6 +361,7 @@ def _CommonChecks(input_api, output_api):
     results.extend(_CheckLayering(input_api, output_api))
     results.extend(_CheckClangTidy(input_api, output_api))
     results.extend(_CheckTestMatrixValid(input_api, output_api))
+    results.extend(_CheckPackageConfigUpToDate(input_api, output_api))
     results.extend(
         input_api.canned_checks.CheckPatchFormatted(input_api, output_api))
     return results

tools/generate_package_config.dart

@@ -7,14 +7,43 @@
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:args/args.dart';
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 import 'package:yaml/yaml.dart';
 
+bool _parseOptions(List<String> args) {
+  const usage = "Usage: dart generate_package_config.dart [flags...]";
+
+  var parser = ArgParser();
+
+  parser.addFlag("help", abbr: "h");
+
+  parser.addFlag("check",
+      abbr: "c",
+      help: "Return with a non-zero exit code if not up-to-date",
+      negatable: false);
+
+  var results = parser.parse(args);
+
+  if (results["help"] as bool) {
+    print("Regenerate the .dart_tool/package_config.json file.");
+    print("");
+    print(usage);
+    print("");
+    print(parser.usage);
+    exit(0);
+  }
+
+  return results["check"] as bool;
+}
+
 final repoRoot = p.dirname(p.dirname(p.fromUri(Platform.script)));
 final configFilePath = p.join(repoRoot, '.dart_tool/package_config.json');
 
 void main(List<String> args) {
+  bool checkOnly = _parseOptions(args);
+
   var packageDirs = [
     ...listSubdirectories('pkg'),
     ...listSubdirectories('third_party/pkg'),
@@ -60,6 +89,24 @@ void main(List<String> args) {
   ];
   packages.sort((a, b) => a["name"].compareTo(b["name"]));
 
+  var configFile = File(p.join(repoRoot, '.dart_tool', 'package_config.json'));
+
+  // Validate the packages entry only, to avoid spurious failures from changes
+  // in the dates embedded in the other entries.
+  if (checkOnly) {
+    var json =
+        jsonDecode(configFile.readAsStringSync()) as Map<dynamic, dynamic>;
+    var oldPackages = json['packages'] as List<dynamic>;
+    if (jsonEncode(packages) == jsonEncode(oldPackages)) {
+      print("Package config up to date");
+      exit(0);
+    } else {
+      print("Package config out of date");
+      print("Run `dart tools/generate_package_config.dart` to update");
+      exit(1);
+    }
+  }
+
   var year = DateTime.now().year;
   var config = <String, dynamic>{
     'copyright': [
@@ -81,8 +128,7 @@ void main(List<String> args) {
 
   // TODO(rnystrom): Consider using package_config_v2 to generate this instead.
   var json = JsonEncoder.withIndent('  ').convert(config);
-  File(p.join(repoRoot, '.dart_tool', 'package_config.json'))
-      .writeAsStringSync(json);
+  configFile.writeAsStringSync(json);
   print('Generated .dart_tool/package_config.dart containing '
       '${packages.length} packages.');
 }