Warn if pub isn't up-to-date in the SDK repo.

lib/src/command_runner.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library pub.command_runner;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:args/command_runner.dart';
 import 'package:http/http.dart' as http;
+import 'package:path/path.dart' as p;
 
 import 'command/build.dart';
 import 'command/cache.dart';
 import 'command/deps.dart';
 import 'command/downgrade.dart';
 import 'command/get.dart';
 import 'command/global.dart';
 import 'command/lish.dart';
 import 'command/list_package_dirs.dart';
 import 'command/run.dart';
 import 'command/serve.dart';
 import 'command/upgrade.dart';
 import 'command/uploader.dart';
 import 'command/version.dart';
 import 'exceptions.dart';
 import 'exit_codes.dart' as exit_codes;
+import 'git.dart' as git;
 import 'http.dart';
 import 'io.dart';
 import 'log.dart' as log;
 import 'sdk.dart' as sdk;
 import 'solver/version_solver.dart';
 import 'utils.dart';
 
 class PubCommandRunner extends CommandRunner {
   String get usageFooter => "See http://dartlang.org/tools/pub for detailed "
       "documentation.";
@@ skipping 43 matching lines @@
     } on UsageException catch (error) {
       log.error(error.message);
       await flushThenExit(exit_codes.USAGE);
     }
     await runCommand(options);
   }
 
   Future runCommand(ArgResults options) async {
     log.withPrejudice = options['with-prejudice'];
 
+    _checkDepsSynced();
+
     if (options['version']) {
       log.message('Pub ${sdk.version}');
       return;
     }
 
     if (options['trace']) {
       log.recordTranscript();
     }
 
     switch (options['verbosity']) {
@@ skipping 41 matching lines @@
       }
 
       await flushThenExit(_chooseExitCode(error));
     }
   }
 
   void printUsage() {
     log.message(usage);
   }
 
+  /// Print a warning if we're running from the Dart SDK repo and pub isn't
+  /// up-to-date.
+  ///
+  /// This is otherwise hard to tell, and can produce confusing behavior issues.
+  void _checkDepsSynced() {
+    if (!runningFromDartRepo) return;
+
+    var deps = readTextFile(p.join(dartRepoRoot, 'DEPS'));
+    var pubRevRegExp = new RegExp(
+        r'^ +"pub_rev": +"@([^"]+)"', multiLine: true);
+    var match = pubRevRegExp.firstMatch(deps);
+    if (match == null) return;
+    var depsRev = match[1];
+
+    var actualRev = git.runSync(["rev-parse", "HEAD"], workingDir: pubRoot)
+        .single;
+
+    if (depsRev == actualRev) return;
+    log.warning(
+        "${log.yellow('Warning:')} the revision of pub in DEPS is "
+            "${log.bold(depsRev)},\n"
+        "but ${log.bold(actualRev)} is checked out in "
+            "${p.relative(pubRoot)}.\n\n");
+  }
+
   /// Returns the appropriate exit code for [exception], falling back on 1 if no
   /// appropriate exit code could be found.
   int _chooseExitCode(exception) {
     while (exception is WrappedException) exception = exception.innerError;
 
     if (exception is HttpException || exception is http.ClientException ||
         exception is SocketException || exception is PubHttpException ||
         exception is DependencyNotFoundException) {
       return exit_codes.UNAVAILABLE;
     } else if (exception is FormatException || exception is DataException) {
@@ skipping 12 matching lines @@
   Future _validatePlatform() async {
     if (Platform.operatingSystem != 'windows') return;
 
     var result = await runProcess('ver', []);
     if (result.stdout.join('\n').contains('XP')) {
       log.error('Sorry, but pub is not supported on Windows XP.');
       await flushThenExit(exit_codes.USAGE);
     }
   }
 }