detect flutter and use default analysis options for flutter

pkg/analyzer/lib/src/context/builder.dart

 // Copyright (c) 2016, 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 analyzer.src.context.context_builder;
 
 import 'dart:collection';
 import 'dart:core';
 
 import 'package:analyzer/context/declared_variables.dart';
@@ skipping 385 matching lines @@
     Map<String, YamlNode> optionMap;
 
     if (optionsFile != null) {
       try {
         optionMap = optionsProvider.getOptionsFromFile(optionsFile);
       } catch (_) {
         // Ignore exceptions thrown while trying to load the options file.
       }
     } else {
       // Search for the default analysis options
-      // TODO(danrubel) check for flutter and use default flutter options
-      Source source =
-          sourceFactory.forUri('package:dart.analysis_options/default.yaml');
+      Source source;
+      // TODO(danrubel) determine if bazel or gn project depends upon flutter
+      if (workspace.hasFlutterDependency) {
+        source =
+            sourceFactory.forUri('package:flutter/analysis_options_user.yaml');
+      }
+      if (source == null || !source.exists()) {
+        source =
+            sourceFactory.forUri('package:dart.analysis_options/default.yaml');
+      }
       if (source.exists()) {
         try {
           optionMap = optionsProvider.getOptionsFromSource(source);
         } catch (_) {
           // Ignore exceptions thrown while trying to load the options file.
         }
       }
     }
 
     if (optionMap != null) {
@@ skipping 308 matching lines @@
   Packages _packages;
 
   _BasicWorkspace._(this.provider, this.root, this._builder);
 
   @override
   Map<String, List<Folder>> get packageMap {
     _packageMap ??= _builder.convertPackagesToMap(packages);
     return _packageMap;
   }
 
+  @override
+  // Alternately, we could check the pubspec for "sdk: flutter"

[Brian Wilkerson, 2017/01/30 20:40:47]

Personally, I think checking the package map is better. We don't currently have
support for reading the pubspec.yaml file, while we do have a package map.

[danrubel, 2017/01/30 20:47:11]

Agreed.

+  bool get hasFlutterDependency => packageMap.containsKey('flutter');
+
   Packages get packages {
     _packages ??= _builder.createPackageMap(root);
     return _packages;
   }
 
   @override
   UriResolver get packageUriResolver =>
       new PackageMapUriResolver(provider, packageMap);
 
   @override
   SourceFactory createSourceFactory(DartSdk sdk) {
     List<UriResolver> resolvers = <UriResolver>[];
     if (sdk != null) {
       resolvers.add(new DartUriResolver(sdk));
     }
     resolvers.add(packageUriResolver);
     resolvers.add(new ResourceUriResolver(provider));
     return new SourceFactory(resolvers, packages, provider);
   }
 
   /**
    * Find the basic workspace that contains the given [path].
    */
   static _BasicWorkspace find(
       ResourceProvider resourceProvider, String path, ContextBuilder builder) {
     return new _BasicWorkspace._(resourceProvider, path, builder);
   }
 }