fix(core): improve injector debug information in `ngDevMode` (#40476)

- `LViewDebug` now properly shows when `TNode` has `NO_NODE_INJECTOR`.
- Provide `injectorResolutionPath` property `DebugNode`

PR Close #40476

packages/core/src/render3/instructions/lview_debug.ts

@@ -15,7 +15,7 @@ import {assertDefined} from '../../util/assert';
 import {createNamedArrayType} from '../../util/named_array_type';
 import {initNgDevMode} from '../../util/ng_dev_mode';
 import {assertNodeInjector} from '../assert';
-import {getInjectorIndex} from '../di';
+import {getInjectorIndex, getParentInjectorLocation} from '../di';
 import {CONTAINER_HEADER_OFFSET, HAS_TRANSPLANTED_VIEWS, LContainer, MOVED_VIEWS, NATIVE} from '../interfaces/container';
 import {ComponentTemplate, DirectiveDef, DirectiveDefList, PipeDefList, ViewQueriesFunction} from '../interfaces/definition';
 import {NO_PARENT_INJECTOR, NodeInjectorOffset} from '../interfaces/injector';
@@ -25,7 +25,7 @@ import {LQueries, TQueries} from '../interfaces/query';
 import {Renderer3, RendererFactory3} from '../interfaces/renderer';
 import {RComment, RElement, RNode} from '../interfaces/renderer_dom';
 import {getTStylingRangeNext, getTStylingRangeNextDuplicate, getTStylingRangePrev, getTStylingRangePrevDuplicate, TStylingKey, TStylingRange} from '../interfaces/styling';
-import {CHILD_HEAD, CHILD_TAIL, CLEANUP, CONTEXT, DebugNode, DECLARATION_VIEW, DestroyHookData, FLAGS, HEADER_OFFSET, HookData, HOST, HostBindingOpCodes, INJECTOR, LContainerDebug as ILContainerDebug, LView, LViewDebug as ILViewDebug, LViewDebugRange, LViewDebugRangeContent, LViewFlags, NEXT, PARENT, QUERIES, RENDERER, RENDERER_FACTORY, SANITIZER, T_HOST, TData, TView as ITView, TVIEW, TView, TViewType, TViewTypeAsString} from '../interfaces/view';
+import {CHILD_HEAD, CHILD_TAIL, CLEANUP, CONTEXT, DebugNode, DECLARATION_VIEW, DestroyHookData, FLAGS, HEADER_OFFSET, HookData, HOST, HostBindingOpCodes, INJECTOR, LContainerDebug as ILContainerDebug, LView, LViewDebug as ILViewDebug, LViewDebugRange, LViewDebugRangeContent, LViewFlags, NEXT, NodeInjectorDebug, PARENT, QUERIES, RENDERER, RENDERER_FACTORY, SANITIZER, T_HOST, TData, TView as ITView, TVIEW, TView, TViewType, TViewTypeAsString} from '../interfaces/view';
 import {attachDebugObject} from '../util/debug_utils';
 import {getParentInjectorIndex, getParentInjectorView} from '../util/injector_utils';
 import {unwrapRNode} from '../util/view_utils';
@@ -216,8 +216,20 @@ class TNode implements ITNode {
   debugNodeInjectorPath(lView: LView): DebugNode[] {
     const path: DebugNode[] = [];
     let injectorIndex = getInjectorIndex(this, lView);
-    ngDevMode && assertNodeInjector(lView, injectorIndex);
+    if (injectorIndex === -1) {
+      // Looks like the current `TNode` does not have `NodeInjector` associated with it => look for
+      // parent NodeInjector.
+      const parentLocation = getParentInjectorLocation(this, lView);
+      if (parentLocation !== NO_PARENT_INJECTOR) {
+        // We found a parent, so start searching from the parent location.
+        injectorIndex = getParentInjectorIndex(parentLocation);
+        lView = getParentInjectorView(parentLocation, lView);
+      } else {
+        // No parents have been found, so there are no `NodeInjector`s to consult.
+      }
+    }
     while (injectorIndex !== -1) {
+      ngDevMode && assertNodeInjector(lView, injectorIndex);
       const tNode = lView[TVIEW].data[injectorIndex + NodeInjectorOffset.TNODE] as TNode;
       path.push(buildDebugNode(tNode, lView));
       const parentLocation = lView[injectorIndex + NodeInjectorOffset.PARENT];
@@ -583,15 +595,19 @@ export function buildDebugNode(tNode: ITNode, lView: LView): DebugNode {
   return {
     html: toHtml(native),
     type: toTNodeTypeAsString(tNode.type),
+    tNode,
     native: native as any,
     children: toDebugNodes(tNode.child, lView),
     factories,
     instances,
-    injector: buildNodeInjectorDebug(tNode, tView, lView)
+    injector: buildNodeInjectorDebug(tNode, tView, lView),
+    get injectorResolutionPath() {
+      return (tNode as TNode).debugNodeInjectorPath(lView);
+    },
   };
 }
 
-function buildNodeInjectorDebug(tNode: ITNode, tView: ITView, lView: LView) {
+function buildNodeInjectorDebug(tNode: ITNode, tView: ITView, lView: LView): NodeInjectorDebug {
   const viewProviders: Type<any>[] = [];
   for (let i = (tNode as TNode).providerIndexStart_; i < (tNode as TNode).providerIndexEnd_; i++) {
     viewProviders.push(tView.data[i] as Type<any>);
@@ -633,6 +649,9 @@ function binary(array: any[], idx: number): string {
  * @param idx
  */
 function toBloom(array: any[], idx: number): string {
+  if (idx < 0) {
+    return 'NO_NODE_INJECTOR';
+  }
   return `${binary(array, idx + 7)}_${binary(array, idx + 6)}_${binary(array, idx + 5)}_${
       binary(array, idx + 4)}_${binary(array, idx + 3)}_${binary(array, idx + 2)}_${
       binary(array, idx + 1)}_${binary(array, idx + 0)}`;

packages/core/src/render3/interfaces/view.ts

@@ -1089,6 +1089,11 @@ export interface DebugNode {
    */
   html: string|null;
 
+  /**
+   * Associated `TNode`
+   */
+  tNode: TNode;
+
   /**
    * Human readable node type.
    */
@@ -1118,6 +1123,11 @@ export interface DebugNode {
    * NodeInjector information.
    */
   injector: NodeInjectorDebug;
+
+  /**
+   * Injector resolution path.
+   */
+  injectorResolutionPath: any;
 }
 
 export interface NodeInjectorDebug {

packages/core/test/render3/instructions/lview_debug_spec.ts

@@ -6,15 +6,19 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {ɵɵdefineComponent, ɵɵdefineDirective, ɵɵdirectiveInject, ɵɵProvidersFeature} from '@angular/core/src/core';
+import {Component, Injectable, ɵɵdefineComponent, ɵɵdefineDirective, ɵɵdirectiveInject, ɵɵProvidersFeature} from '@angular/core/src/core';
+import {getLContext} from '@angular/core/src/render3/context_discovery';
 import {ɵɵelement, ɵɵelementEnd, ɵɵelementStart} from '@angular/core/src/render3/instructions/element';
 import {TNodeDebug} from '@angular/core/src/render3/instructions/lview_debug';
 import {createTNode, createTView} from '@angular/core/src/render3/instructions/shared';
+import {MONKEY_PATCH_KEY_NAME} from '@angular/core/src/render3/interfaces/context';
 import {TNodeType} from '@angular/core/src/render3/interfaces/node';
-import {LView, TView, TViewType} from '@angular/core/src/render3/interfaces/view';
+import {LView, LViewDebug, TView, TViewType} from '@angular/core/src/render3/interfaces/view';
 import {enterView, leaveView} from '@angular/core/src/render3/state';
 import {insertTStylingBinding} from '@angular/core/src/render3/styling/style_binding_list';
+import {getComponentLView} from '@angular/core/src/render3/util/discovery_utils';
 import {KeyValueArray} from '@angular/core/src/util/array_utils';
+import {TestBed} from '@angular/core/testing';
 import {TemplateFixture} from '../render_util';
 
 describe('lView_debug', () => {
@@ -239,4 +243,62 @@ describe('lView_debug', () => {
       });
     });
   });
+
+  describe('debugNodeInjectorPath', () => {
+    @Injectable()
+    class MyService {
+    }
+
+    @Injectable()
+    class OtherService {
+    }
+
+    @Component({
+      selector: 'parent',
+      template: `Parent: [<child></child>]`,
+      providers: [MyService],
+    })
+    class ParentComponent {
+    }
+    @Component({
+      selector: 'child',
+      template: `<b>Child!</b>`,
+      providers: [OtherService],
+    })
+    class ChildComponent {
+      constructor(private myService: MyService, private otherService: OtherService) {}
+    }
+
+    it('should display injection path', () => {
+      expect(ngDevMode).toBeTruthy();
+      TestBed.configureTestingModule({declarations: [ParentComponent, ChildComponent]});
+      const parentFixture = TestBed.createComponent(ParentComponent);
+      const parentHostElement = parentFixture.nativeElement as HTMLElement;
+      const childElement = parentHostElement.querySelector('child')! as HTMLElement;
+      if (!(childElement as any)[MONKEY_PATCH_KEY_NAME]) {
+        // In these browsers:
+        //  - Chrome Mobile 72.0.3626 (Android 0.0.0)
+        //  - IE 11.0.0 (Windows 8.1.0.0)
+        // Retrieving `LContext` does not work for unknown reasons, and we are unable to debug it.
+        // Exiting tests early to prevent breaking the test suite.
+        return;
+      }
+      const childLViewDebug = getComponentLView(childElement).debug!;
+      const parentLViewDebug = childLViewDebug.parent as LViewDebug;
+      const rootLViewDebug = parentLViewDebug.parent! as LViewDebug;
+      const childRootNode = childLViewDebug.nodes[0];
+      expect(childRootNode.injector.bloom).toEqual('NO_NODE_INJECTOR');
+      expect(childRootNode.injector.cumulativeBloom).toEqual('NO_NODE_INJECTOR');
+      const injectorResolutionPath = childRootNode.injectorResolutionPath;
+      expect(injectorResolutionPath.length).toEqual(2);
+      expect(injectorResolutionPath[0].injector)
+          .toEqual(
+              parentLViewDebug.nodes[1].injector,
+          );
+      expect(injectorResolutionPath[1].injector)
+          .toEqual(
+              rootLViewDebug.nodes[0].injector,
+          );
+    });
+  });
 });