Embedded options discovery (#24943).

pkg/analysis_server/lib/src/context_manager.dart

Index: pkg/analysis_server/lib/src/context_manager.dart
diff --git a/pkg/analysis_server/lib/src/context_manager.dart b/pkg/analysis_server/lib/src/context_manager.dart
index 767875ba42fafd915ecd96970444a459b825f228..aa34cf96f7e30e336bf06dde429e721ca1055a99 100644
--- a/pkg/analysis_server/lib/src/context_manager.dart
+++ b/pkg/analysis_server/lib/src/context_manager.dart
@@ -29,6 +29,7 @@ import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/task/options.dart';
 import 'package:analyzer/src/util/absolute_path.dart';
+import 'package:analyzer/src/util/yaml.dart';
 import 'package:package_config/packages.dart';
 import 'package:package_config/packages_file.dart' as pkgfile show parse;
 import 'package:package_config/src/packages_impl.dart' show MapPackages;
@@ -500,15 +501,28 @@ class ContextManagerImpl implements ContextManager {
       }
     });
 
-    // In case options files are removed, revert to default options.
+    // In case options files are removed, revert to defaults.
     if (optionsRemoved) {
+      // Start with defaults.
       info.context.analysisOptions = new AnalysisOptionsImpl();
+
+      // Apply inherited options.
+      YamlMap embeddedOptions = _getEmbeddedOptions(info.context);
+      if (embeddedOptions != null) {
+        configureContextOptions(info.context, embeddedOptions);
+      }
       return;
     }
 
+    // Check for embedded options.
+    YamlMap embeddedOptions = _getEmbeddedOptions(info.context);
+    if (embeddedOptions != null) {
+      options = new Merger().merge(embeddedOptions, options);
+    }
+
     // Analysis options are processed 'in-line'.
     var analyzer = options[AnalyzerOptions.analyzer];
-    if (analyzer is! YamlMap) {
+    if (analyzer is! Map) {
       // No options for analyzer.
       return;
     }
@@ -1008,6 +1022,20 @@ class ContextManagerImpl implements ContextManager {
     return packageSpec;
   }
 
+  /// Get analysis options associated with an `_embedder.yaml`. If there is
+  /// more than one `_embedder.yaml` associated with the given context, `null`
+  /// is returned.
+  YamlMap _getEmbeddedOptions(AnalysisContext context) {
+    if (context is InternalAnalysisContext) {
+      EmbedderYamlLocator locator = context.embedderYamlLocator;
+      Iterable<YamlMap> maps = locator.embedderYamls.values;
+      if (maps.length == 1) {
+        return maps.first;
+      }
+    }
+    return null;
+  }
+
   /**
    * Return the [ContextInfo] for the "innermost" context whose associated
    * folder is or contains the given path.  ("innermost" refers to the nesting
@@ -1454,6 +1482,11 @@ class PackagesFileDisposition extends FolderDisposition {
   @override
   final Packages packages;
 
+  PackagesFileDisposition(this.packages) {}
+
+  @override
+  String get packageRoot => null;
+
   Map<String, List<Folder>> buildPackageMap(ResourceProvider resourceProvider) {
     Map<String, List<Folder>> packageMap = <String, List<Folder>>{};
     if (packages == null) {
@@ -1468,18 +1501,12 @@ class PackagesFileDisposition extends FolderDisposition {
     return packageMap;
   }
 
-  PackagesFileDisposition(this.packages) {}
-
-  @override
-  String get packageRoot => null;
-
   @override
   Iterable<UriResolver> createPackageUriResolvers(
       ResourceProvider resourceProvider) {
     if (packages != null) {
       // Construct package map for the SdkExtUriResolver.
-      Map<String, List<Folder>> packageMap =
-          buildPackageMap(resourceProvider);
+      Map<String, List<Folder>> packageMap = buildPackageMap(resourceProvider);
       return <UriResolver>[new SdkExtUriResolver(packageMap)];
     } else {
       return const <UriResolver>[];