fix(core): don’t stop change detection because of errors

- prevents unsubscribing from the zone on error
- prevents unsubscribing from directive `EventEmitter`s on error
- prevents detaching views in dev mode if there on error
- ensures that `ngOnInit` is only called 1x (also in prod mode)

Fixes #9531
Fixes #2413
Fixes #15925

packages/core/src/application_ref.ts

@@ -560,6 +560,9 @@ export class ApplicationRef_ extends ApplicationRef {
       if (this._enforceNoNewChanges) {
         this._views.forEach((view) => view.checkNoChanges());
       }
+    } catch (e) {
+      // Attention: Don't rethrow as it could cancel subscriptions to Observables!
+      this._exceptionHandler.handleError(e);
     } finally {
       this._runningTick = false;
       wtfLeave(scope);

packages/core/src/view/element.ts

@@ -189,7 +189,14 @@ export function listenToElementOutputs(view: ViewData, compView: ViewData, def:
 }
 
 function renderEventHandlerClosure(view: ViewData, index: number, eventName: string) {
-  return (event: any) => dispatchEvent(view, index, eventName, event);
+  return (event: any) => {
+    try {
+      return dispatchEvent(view, index, eventName, event);
+    } catch (e) {
+      // Attention: Don't rethrow, to keep in sync with directive events.
+      view.root.errorHandler.handleError(e);
+    }
+  }
 }
 
 

packages/core/src/view/provider.ts

@@ -148,7 +148,14 @@ export function createDirectiveInstance(view: ViewData, def: NodeDef): any {
 }
 
 function eventHandlerClosure(view: ViewData, index: number, eventName: string) {
-  return (event: any) => dispatchEvent(view, index, eventName, event);
+  return (event: any) => {
+    try {
+      return dispatchEvent(view, index, eventName, event);
+    } catch (e) {
+      // Attention: Don't rethrow, as it would cancel Observable subscriptions!
+      view.root.errorHandler.handleError(e);
+    }
+  }
 }
 
 export function checkAndUpdateDirectiveInline(

packages/core/src/view/services.ts

@@ -9,6 +9,7 @@
 import {isDevMode} from '../application_ref';
 import {DebugElement, DebugNode, EventListener, getDebugNode, indexDebugNode, removeDebugNodeFromIndex} from '../debug/debug_node';
 import {Injector} from '../di';
+import {ErrorHandler} from '../error_handler';
 import {NgModuleRef} from '../linker/ng_module_factory';
 import {Renderer2, RendererFactory2, RendererStyleFlags2, RendererType2} from '../render/api';
 import {Sanitizer} from '../security';
@@ -104,11 +105,12 @@ function createRootData(
     elInjector: Injector, ngModule: NgModuleRef<any>, rendererFactory: RendererFactory2,
     projectableNodes: any[][], rootSelectorOrNode: any): RootData {
   const sanitizer = ngModule.injector.get(Sanitizer);
+  const errorHandler = ngModule.injector.get(ErrorHandler);
   const renderer = rendererFactory.createRenderer(null, null);
   return {
     ngModule,
     injector: elInjector, projectableNodes,
-    selectorOrNode: rootSelectorOrNode, sanitizer, rendererFactory, renderer
+    selectorOrNode: rootSelectorOrNode, sanitizer, rendererFactory, renderer, errorHandler
   };
 }
 
@@ -439,7 +441,6 @@ function callWithDebugContext(action: DebugAction, fn: any, self: any, args: any
     if (isViewDebugError(e) || !_currentView) {
       throw e;
     }
-    _currentView.state |= ViewState.Errored;
     throw viewWrappedDebugError(e, getCurrentDebugContext() !);
   }
 }

packages/core/src/view/types.ts

@@ -7,6 +7,7 @@
  */
 
 import {Injector} from '../di';
+import {ErrorHandler} from '../error_handler';
 import {NgModuleRef} from '../linker/ng_module_factory';
 import {QueryList} from '../linker/query_list';
 import {TemplateRef} from '../linker/template_ref';
@@ -323,13 +324,14 @@ export interface ViewData {
  * Bitmask of states
  */
 export const enum ViewState {
-  FirstCheck = 1 << 0,
-  Attached = 1 << 1,
-  ChecksEnabled = 1 << 2,
-  Errored = 1 << 3,
+  BeforeFirstCheck = 1 << 0,
+  FirstCheck = 1 << 1,
+  Attached = 1 << 2,
+  ChecksEnabled = 1 << 3,
   Destroyed = 1 << 4,
 
   CatDetectChanges = Attached | ChecksEnabled,
+  CatInit = BeforeFirstCheck | CatDetectChanges
 }
 
 export interface DisposableFn { (): void; }
@@ -432,6 +434,7 @@ export interface RootData {
   selectorOrNode: any;
   renderer: Renderer2;
   rendererFactory: RendererFactory2;
+  errorHandler: ErrorHandler;
   sanitizer: Sanitizer;
 }
 

packages/core/src/view/util.ts

@@ -100,10 +100,10 @@ export function checkAndUpdateBinding(
 export function checkBindingNoChanges(
     view: ViewData, def: NodeDef, bindingIdx: number, value: any) {
   const oldValue = view.oldValues[def.bindingIndex + bindingIdx];
-  if ((view.state & ViewState.FirstCheck) || !devModeEqual(oldValue, value)) {
+  if ((view.state & ViewState.BeforeFirstCheck) || !devModeEqual(oldValue, value)) {
     throw expressionChangedAfterItHasBeenCheckedError(
         Services.createDebugContext(view, def.index), oldValue, value,
-        (view.state & ViewState.FirstCheck) !== 0);
+        (view.state & ViewState.BeforeFirstCheck) !== 0);
   }
 }
 

packages/core/src/view/view.ts

@@ -211,7 +211,7 @@ function createView(
     viewContainerParent: null, parentNodeDef,
     context: null,
     component: null, nodes,
-    state: ViewState.FirstCheck | ViewState.CatDetectChanges, root, renderer,
+    state: ViewState.CatInit, root, renderer,
     oldValues: new Array(def.bindingCount), disposables
   };
   return view;
@@ -323,6 +323,12 @@ export function checkNoChangesView(view: ViewData) {
 }
 
 export function checkAndUpdateView(view: ViewData) {
+  if (view.state & ViewState.BeforeFirstCheck) {
+    view.state &= ~ViewState.BeforeFirstCheck;
+    view.state |= ViewState.FirstCheck;
+  } else {
+    view.state &= ~ViewState.FirstCheck;
+  }
   Services.updateDirectives(view, CheckType.CheckAndUpdate);
   execEmbeddedViewsAction(view, ViewAction.CheckAndUpdate);
   execQueriesAction(
@@ -345,7 +351,6 @@ export function checkAndUpdateView(view: ViewData) {
   if (view.def.flags & ViewFlags.OnPush) {
     view.state &= ~ViewState.ChecksEnabled;
   }
-  view.state &= ~ViewState.FirstCheck;
 }
 
 export function checkAndUpdateNode(
@@ -453,7 +458,7 @@ function checkNoChangesQuery(view: ViewData, nodeDef: NodeDef) {
   if (queryList.dirty) {
     throw expressionChangedAfterItHasBeenCheckedError(
         Services.createDebugContext(view, nodeDef.index), `Query ${nodeDef.query!.id} not dirty`,
-        `Query ${nodeDef.query!.id} dirty`, (view.state & ViewState.FirstCheck) !== 0);
+        `Query ${nodeDef.query!.id} dirty`, (view.state & ViewState.BeforeFirstCheck) !== 0);
   }
 }
 
@@ -543,13 +548,13 @@ function callViewAction(view: ViewData, action: ViewAction) {
   switch (action) {
     case ViewAction.CheckNoChanges:
       if ((viewState & ViewState.CatDetectChanges) === ViewState.CatDetectChanges &&
-          (viewState & (ViewState.Errored | ViewState.Destroyed)) === 0) {
+          (viewState & ViewState.Destroyed) === 0) {
         checkNoChangesView(view);
       }
       break;
     case ViewAction.CheckAndUpdate:
       if ((viewState & ViewState.CatDetectChanges) === ViewState.CatDetectChanges &&
-          (viewState & (ViewState.Errored | ViewState.Destroyed)) === 0) {
+          (viewState & ViewState.Destroyed) === 0) {
         checkAndUpdateView(view);
       }
       break;