Initial validation of build_runner dependency and version

webdev/bin/webdev.dart

@@ -12,11 +12,21 @@ import 'package:webdev/src/webdev_command_runner.dart';
 
 Future main(List<String> args) async {
   try {
-    await webdevCommandRunner().run(args);
+    exitCode = await run(args);
   } on UsageException catch (e) {
     print(yellow.wrap(e.message));
     print(' ');
     print(e.usage);
     exitCode = ExitCode.usage.code;
+  } on PackageException catch (e) {
+    print(yellow.wrap('Could not run in the current directory.'));
+    for (var detail in e.details) {
+      print(detail.error);
+      if (detail.description != null) {
+        print('  ${detail.description}');
+      }
+    }
+
+    exitCode = ExitCode.config.code;
   }
 }

webdev/lib/src/command/build_command.dart

@@ -14,5 +14,5 @@ class BuildCommand extends BuildRunnerCommandBase {
   final description = 'Run builders to build a package.';
 
   @override
-  Future run() => runCore('build');
+  Future<int> run() => runCore('build');
 }

webdev/lib/src/command/build_runner_command_base.dart

@@ -3,15 +3,17 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:io';
+import 'dart:io' hide exitCode, exit;
 import 'dart:isolate';
 
 import 'package:args/command_runner.dart';
 import 'package:stack_trace/stack_trace.dart';
 
+import '../pubspec.dart';
+
 /// Extend to get a command with the arguments common to all build_runner
 /// commands.
-abstract class BuildRunnerCommandBase extends Command {
+abstract class BuildRunnerCommandBase extends Command<int> {
   BuildRunnerCommandBase() {
     // TODO(nshahan) Expose more common args passed to build_runner commands.
     // build_runner might expose args for use in wrapping scripts like this one.
@@ -25,9 +27,13 @@ abstract class BuildRunnerCommandBase extends Command {
           help: 'Enables verbose logging.');
   }
 
-  Future runCore(String command) async {
+  Future<int> runCore(String command) async {
+    await checkPubspecLock();
+
     final arguments = [command]..addAll(argResults.arguments);
 
+    var exitCode = 0;
+
     // Heavily inspired by dart-lang/build @ 0c77443dd7
     // /build_runner/bin/build_runner.dart#L58-L85
     var exitPort = new ReceivePort();
@@ -62,6 +68,8 @@ abstract class BuildRunnerCommandBase extends Command {
     await exitPort.first;
     await errorListener.cancel();
     await exitCodeListener?.cancel();
+
+    return exitCode;
   }
 }
 

webdev/lib/src/command/serve_command.dart

@@ -31,5 +31,5 @@ class ServeCommand extends BuildRunnerCommandBase {
   }
 
   @override
-  Future run() => runCore('serve');
+  Future<int> run() => runCore('serve');
 }

webdev/lib/src/pubspec.dart

@@ -0,0 +1,90 @@
+// Copyright (c) 2018, 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.
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:pub_semver/pub_semver.dart';
+import 'package:yaml/yaml.dart';
+
+import 'util.dart';
+
+class PackageException implements Exception {
+  final List<PackageExceptionDetails> details;
+
+  PackageException._(this.details);
+}
+
+class PackageExceptionDetails {
+  final String error;
+  final String description;
+
+  const PackageExceptionDetails._(this.error, {this.description});
+
+  static const noPubspecLock = const PackageExceptionDetails._(
+      '`pubspec.lock` does not exist.',
+      description:
+          'Run `webdev` in a Dart package directory. Run `pub get` first.');
+
+  static const noBuildRunnerDep = const PackageExceptionDetails._(
+      'A dependency on `build_runner` was not found.',
+      description:
+          'You must have a dependency on `build_runner` in `pubspec.yaml`. '
+          'It can be in either `dependencies` or `dev_dependencies`.');
+
+  @override
+  String toString() => [error, description].join('\n');
+}
+
+Future checkPubspecLock() async {
+  var file = new File('pubspec.lock');
+  if (!file.existsSync()) {
+    throw new PackageException._([PackageExceptionDetails.noPubspecLock]);
+  }
+
+  var pubspecLock = loadYaml(await file.readAsString()) as YamlMap;
+
+  var packages = pubspecLock['packages'] as YamlMap;
+
+  var issues = <PackageExceptionDetails>[];
+
+  var buildRunner = packages['build_runner'] as YamlMap;
+  if (buildRunner == null) {
+    issues.add(PackageExceptionDetails.noBuildRunnerDep);
+  } else {
+    var dependency = buildRunner['dependency'] as String;
+    if (!dependency.startsWith('direct ')) {
+      issues.add(PackageExceptionDetails.noBuildRunnerDep);
+    }
+
+    var version = buildRunner['version'] as String;
+    if (version == null) {
+      // TODO: warning?
+    } else {
+      var buildRunnerVersion = new Version.parse(version);
+
+      if (!supportedBuildRunnerVersionRange.allows(buildRunnerVersion)) {
+        var error = 'The `build_runner` version – $buildRunnerVersion – is not '
+            'within the supported range – $supportedBuildRunnerVersionRange.';
+        issues.add(new PackageExceptionDetails._(error));
+      }
+    }
+
+    var source = buildRunner['source'] as String;
+    if (source == 'hosted') {
+      //var description = buildRunner['description'] as YamlMap;
+      // TODO: check for `{url: https://pub.dartlang.org, name: build_runner}`
+      // If not, print a warning
+    } else {
+      // TODO: print a warning that we're assuming hosted
+    }
+  }
+
+  // TODO: validate build_web_compilers
+  //var buldWebCompilers = packages['build_web_compilers'];
+
+  if (issues.isNotEmpty) {
+    throw new PackageException._(issues);
+  }
+}

webdev/lib/src/util.dart

@@ -0,0 +1,11 @@
+// Copyright (c) 2018, 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.
+
+import 'package:pub_semver/pub_semver.dart';
+
+final supportedBuildRunnerVersionRange = new VersionRange(
+    min: new Version(0, 8, 0),
+    includeMin: true,
+    max: new Version(0, 9, 0),
+    includeMax: false);

webdev/lib/src/webdev_command_runner.dart

@@ -2,13 +2,21 @@
 // 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.
 
+import 'dart:async';
+
 import 'package:args/command_runner.dart';
 
 import 'command/build_command.dart';
 import 'command/serve_command.dart';
 
-/// All available top level commands.
-CommandRunner webdevCommandRunner() =>
-    new CommandRunner('webdev', 'A tool to develop Dart web projects.')
-      ..addCommand(new BuildCommand())
-      ..addCommand(new ServeCommand());
+export 'pubspec.dart' show PackageException;
+
+Future<int> run(List<String> args) async {
+  var runner =
+      new CommandRunner<int>('webdev', 'A tool to develop Dart web projects.')
+        ..addCommand(new BuildCommand())
+        ..addCommand(new ServeCommand());
+
+  // In the case of `help`, `null` is returned. Treat that as success.
+  return await runner.run(args) ?? 0;
+}

webdev/pubspec.yaml

@@ -10,10 +10,14 @@ environment:
 dependencies:
   args: ^1.2.0
   io: ^0.3.2+1
+  pub_semver: ^1.3.2
   stack_trace: ^1.9.2
+  yaml: ^2.1.13
 
 dev_dependencies:
+  path: ^1.5.1
   test: ^0.12.0
+  test_descriptor: ^1.0.3
   test_process: ^1.0.1
 
 executables:

webdev/test/integration_test.dart

@@ -4,12 +4,16 @@
 
 import 'dart:io';
 
+import 'package:path/path.dart' as p;
 import 'package:test/test.dart';
+import 'package:test_descriptor/test_descriptor.dart' as d;
 import 'package:test_process/test_process.dart';
 
+final _webdevBin = p.absolute('bin/webdev.dart');
+
 void main() {
   test('README contains help output', () async {
-    var process = await TestProcess.start('dart', ['bin/webdev.dart']);
+    var process = await TestProcess.start('dart', [_webdevBin]);
 
     var output = (await process.stdoutStream().join('\n')).trim();
 
@@ -22,8 +26,7 @@ void main() {
   });
 
   test('non-existant commands create errors', () async {
-    var process =
-        await TestProcess.start('dart', ['bin/webdev.dart', 'monkey']);
+    var process = await TestProcess.start('dart', [_webdevBin, 'monkey']);
 
     var output = (await process.stdoutStream().join('\n')).trim();
 
@@ -33,7 +36,40 @@ void main() {
   });
 
   test('should fail in a package without a build_runner dependency', () async {
-    var process = await TestProcess.start('dart', ['bin/webdev.dart', 'serve']);
-    await process.shouldExit(255);
+    var process = await TestProcess.start('dart', [_webdevBin, 'serve']);
+    var output = (await process.stdoutStream().join('\n')).trim();
+
+    expect(output, contains(r'''Could not run in the current directory.
+A dependency on `build_runner` was not found.'''));
+    await process.shouldExit(78);
+  });
+
+  group('should fail when `build_runner` is the wrong version', () {
+    for (var version in ['0.7.13+1', '0.9.0']) {
+      test(version, () async {
+        await d.file('pubspec.lock', '''
+# Copy-pasted from a valid run
+packages:
+  build_runner:
+    dependency: "direct main"
+    description:
+      name: build_runner
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "$version"
+''').create();
+
+        var process = await TestProcess.start('dart', [_webdevBin, 'build'],
+            workingDirectory: d.sandbox);
+        var output = (await process.stdoutStream().join('\n')).trim();
+
+        expect(output, contains('Could not run in the current directory.'));
+        expect(
+            output,
+            contains('The `build_runner` version – $version – '
+                'is not within the supported range – >=0.8.0 <0.9.0.'));
+        await process.shouldExit(78);
+      });
+    }
   });
 }