feat(change_detection): provide error context for change detection errors

modules/angular2/src/core/application_common.ts

@@ -128,7 +128,7 @@ function _injectorBindings(appComponentType): List<Type | Binding | List<any>> {
     DirectiveResolver,
     Parser,
     Lexer,
-    bind(ExceptionHandler).toFactory(() => new ExceptionHandler(DOM)),
+    bind(ExceptionHandler).toFactory(() => new ExceptionHandler(DOM), []),
     bind(XHR).toValue(new XHRImpl()),
     ComponentUrlMapper,
     UrlResolver,

modules/angular2/src/core/compiler/element_injector.ts

@@ -496,10 +496,9 @@ export class ElementInjector extends TreeNode<ElementInjector> implements Depend
 
   private _debugContext(): any {
     var p = this._preBuiltObjects;
-    var element = isPresent(p.elementRef) ? p.elementRef.nativeElement : null;
-    var hostRef = p.view.getHostElement();
-    var componentElement = isPresent(hostRef) ? hostRef.nativeElement : null;
-    return new _Context(element, componentElement, this._injector);
+    var index = p.elementRef.boundElementIndex - p.view.elementOffset;
+    var c = this._preBuiltObjects.view.getDebugContext(index, null);
+    return new _Context(c["element"], c["componentElement"], c["injector"]);
   }
 
   private _reattachInjectors(imperativelyCreatedInjector: Injector): void {
@@ -573,6 +572,8 @@ export class ElementInjector extends TreeNode<ElementInjector> implements Depend
 
   getComponent(): any { return this._strategy.getComponent(); }
 
+  getInjector(): Injector { return this._injector; }
+
   getElementRef(): ElementRef { return this._preBuiltObjects.elementRef; }
 
   getViewContainerRef(): ViewContainerRef {

modules/angular2/src/core/compiler/view.ts

@@ -1,4 +1,11 @@
-import {ListWrapper, MapWrapper, Map, StringMapWrapper, List} from 'angular2/src/facade/collection';
+import {
+  ListWrapper,
+  MapWrapper,
+  Map,
+  StringMapWrapper,
+  List,
+  StringMap
+} from 'angular2/src/facade/collection';
 import {
   AST,
   Locals,
@@ -202,7 +209,36 @@ export class AppView implements ChangeDispatcher, RenderEventDispatcher {
 
   getHostElement(): ElementRef {
     var boundElementIndex = this.mainMergeMapping.hostElementIndicesByViewIndex[this.viewOffset];
-    return this.elementRefs[boundElementIndex];
+    return isPresent(boundElementIndex) ? this.elementRefs[boundElementIndex] : null;
+  }
+
+  getDebugContext(elementIndex: number, directiveIndex: DirectiveIndex): StringMap<string, any> {
+    try {
+      var offsettedIndex = this.elementOffset + elementIndex;
+      var hasRefForIndex = offsettedIndex < this.elementRefs.length;
+
+      var elementRef = hasRefForIndex ? this.elementRefs[this.elementOffset + elementIndex] : null;
+      var host = this.getHostElement();
+      var ei = hasRefForIndex ? this.elementInjectors[this.elementOffset + elementIndex] : null;
+
+      var element = isPresent(elementRef) ? elementRef.nativeElement : null;
+      var componentElement = isPresent(host) ? host.nativeElement : null;
+      var directive = isPresent(directiveIndex) ? this.getDirectiveFor(directiveIndex) : null;
+      var injector = isPresent(ei) ? ei.getInjector() : null;
+
+      return {
+        element: element,
+        componentElement: componentElement,
+        directive: directive,
+        context: this.context,
+        locals: _localsToStringMap(this.locals),
+        injector: injector
+      };
+    } catch (e) {
+      // TODO: vsavkin log the exception once we have a good way to log errors and warnings
+      // if an error happens during getting the debug context, we return an empty map.
+      return {};
+    }
   }
 
   getDetectorFor(directive: DirectiveIndex): any {
@@ -252,6 +288,16 @@ export class AppView implements ChangeDispatcher, RenderEventDispatcher {
   }
 }
 
+function _localsToStringMap(locals: Locals): StringMap<string, any> {
+  var res = {};
+  var c = locals;
+  while (isPresent(c)) {
+    res = StringMapWrapper.merge(res, MapWrapper.toStringMap(c.current));
+    c = c.parent;
+  }
+  return res;
+}
+
 /**
  *
  */

modules/angular2/src/core/exception_handler.ts

@@ -50,7 +50,7 @@ export class ExceptionHandler {
 
     if (isPresent(stackTrace) && isBlank(originalStack)) {
       this.logger.log("STACKTRACE:");
-      this.logger.log(this._longStackTrace(stackTrace))
+      this.logger.log(this._longStackTrace(stackTrace));
     }
 
     if (isPresent(reason)) {