angular · ryan-bendel · Aug 13, 2025 · JeanMeche · Dec 1, 2025 · ryan-bendel
diff --git a/adev/src/content/guide/routing/data-resolvers.md b/adev/src/content/guide/routing/data-resolvers.md
@@ -205,11 +205,11 @@ export class App {
      map(event => {
        if (event instanceof NavigationError) {
          this.lastFailedUrl.set(event.url);
-  
+
          if (event.error) {
            console.error('Navigation error', event.error)
          }
-  
+
          return 'Navigation failed. Please try again.';
        }
        return '';

diff --git a/goldens/public-api/compiler-cli/error_code.api.md b/goldens/public-api/compiler-cli/error_code.api.md
@@ -78,6 +78,7 @@ export enum ErrorCode {
    INLINE_TYPE_CTOR_REQUIRED = 8901,
    INTERPOLATED_SIGNAL_NOT_INVOKED = 8109,
    INVALID_BANANA_IN_BOX = 8101,
+    ISOLATED_SHADOW_DOM_INVALID_CONTENT_PROJECTION = 2028,
    LET_USED_BEFORE_DEFINITION = 8016,
    LOCAL_COMPILATION_UNRESOLVED_CONST = 11001,
    LOCAL_COMPILATION_UNSUPPORTED_EXPRESSION = 11003,

diff --git a/goldens/public-api/platform-browser/errors.api.md b/goldens/public-api/platform-browser/errors.api.md
@@ -23,6 +23,8 @@ export const enum RuntimeErrorCode {
    // (undocumented)
    SANITIZATION_UNSAFE_SCRIPT = 5200,
    // (undocumented)
+    SHADOWDOM_NOT_SUPPORTED_IN_SSR = 5106,
+    // (undocumented)
    TESTABILITY_NOT_FOUND = 5103,
    // (undocumented)
    UNEXPECTED_SYNTHETIC_PROPERTY = 5105,

diff --git a/integration/cli-hello-world-lazy/size.json b/integration/cli-hello-world-lazy/size.json
@@ -1,5 +1,5 @@
 {
-  "dist/main.js": 108611,
-  "dist/polyfills.js": 34169,
-  "dist/lazy.routes-[hash].js": 361
+  "dist/main.js": 113764,
+  "dist/polyfills.js": 34585,
+  "dist/lazy.routes-[hash].js": 348
 }
diff --git a/integration/defer/size.json b/integration/defer/size.json
@@ -1,5 +1,5 @@
 {
-  "dist/main.js": 12709,
+  "dist/main.js": 16485,
  "dist/polyfills.js": 35677,
-  "dist/defer.component-[hash].js": 345
+  "dist/defer.component-[hash].js": 331
 }
diff --git a/integration/legacy-animations-async/size.json b/integration/legacy-animations-async/size.json
@@ -1,6 +1,6 @@
 {
-  "dist/main.js": 97227,
+  "dist/main.js": 102215,
  "dist/polyfills.js": 35677,
-  "dist/browser-[hash].js": 63949,
-  "dist/open-close.component-[hash].js": 1218
+  "dist/browser-[hash].js": 64236,
+  "dist/open-close.component-[hash].js": 1189
 }
diff --git a/integration/legacy-animations/size.json b/integration/legacy-animations/size.json
@@ -1,5 +1,5 @@
 {
-  "dist/main.js": 153915,
-  "dist/polyfills.js": 34023,
-  "dist/open-close.component-[hash].js": 1190
+  "dist/main.js": 159053,
+  "dist/polyfills.js": 35677,
+  "dist/open-close.component-[hash].js": 1131
 }
diff --git a/integration/platform-server-hydration/size.json b/integration/platform-server-hydration/size.json
@@ -1,5 +1,5 @@
 {
-  "dist/browser/main-[hash].js": 227093,
-  "dist/browser/polyfills-[hash].js": 34544,
+  "dist/browser/main-[hash].js": 234529,
+  "dist/browser/polyfills-[hash].js": 35677,
  "dist/browser/event-dispatch-contract.min.js": 476
 }
diff --git a/integration/standalone-bootstrap/size.json b/integration/standalone-bootstrap/size.json
@@ -1,4 +1,4 @@
 {
-  "dist/main.js": 89237,
+  "dist/main.js": 97201,
  "dist/polyfills.js": 35677
 }
diff --git a/packages/compiler-cli/src/ngtsc/annotations/component/src/handler.ts b/packages/compiler-cli/src/ngtsc/annotations/component/src/handler.ts
@@ -908,6 +908,24 @@ export class ComponentDecoratorHandler
      }
    }

+    // Check for ng-content in IsolatedShadowDom components
+    if (encapsulation === ViewEncapsulation.ExperimentalIsolatedShadowDom) {
+      const contentNode = findContentNode(template.nodes);
+      if (contentNode !== null) {
+        if (diagnostics === undefined) {
+          diagnostics = [];
+        }
+        diagnostics.push(
+          makeDiagnostic(
+            ErrorCode.ISOLATED_SHADOW_DOM_INVALID_CONTENT_PROJECTION,
+            component.get('template') ?? node.name,
+            `ng-content projection is not supported with ViewEncapsulation.ExperimentalIsolatedShadowDom. ` +
+              `Use native <slot> elements instead. Content will remain in the light DOM and be projected via slots.`,
+          ),
+        );
+      }
+    }
+
    // If inline styles were preprocessed use those
    let inlineStyles: string[] | null = null;
    if (this.preanalyzeStylesCache.has(node)) {
@@ -2637,3 +2655,24 @@ function validateStandaloneImports(
 function isDefaultImport(node: ts.ImportDeclaration): boolean {
  return node.importClause !== undefined && node.importClause.namedBindings === undefined;
 }
+
+/**
+ * Recursively searches through template nodes to find a Content node (ng-content).
+ * Returns the first Content node found, or null if none exist.
+ */
+function findContentNode(nodes: any[]): any | null {
+  for (const node of nodes) {
+    // Check if this is a Content node (ng-content)
+    if (node.name === 'ng-content') {
+      return node;
+    }
+    // Recursively check children
+    if (node.children && node.children.length > 0) {
+      const found = findContentNode(node.children);
+      if (found !== null) {
+        return found;
+      }
+    }
+  }
+  return null;
+}
diff --git a/packages/compiler-cli/src/ngtsc/diagnostics/src/error_code.ts b/packages/compiler-cli/src/ngtsc/diagnostics/src/error_code.ts
@@ -184,6 +184,12 @@ export enum ErrorCode {
   */
  COMPONENT_ANIMATIONS_CONFLICT = 2027,

+  /**
+   * Raised when a component with `ViewEncapsulation.ExperimentalIsolatedShadowDom` uses `<ng-content>`.
+   * ExperimentalIsolatedShadowDom components must use native `<slot>` elements instead.
+   */
+  ISOLATED_SHADOW_DOM_INVALID_CONTENT_PROJECTION = 2028,
+
  SYMBOL_NOT_EXPORTED = 3001,
  /**
   * Raised when a relationship between directives and/or pipes would cause a cyclic import to be

diff --git a/packages/core/src/core.ts b/packages/core/src/core.ts
@@ -105,6 +105,9 @@ export {createComponent, reflectComponentType, ComponentMirror} from './render3/
 export {isStandalone} from './render3/def_getters';
 export {AfterRenderRef} from './render3/after_render/api';
 export {publishExternalGlobalUtil as ɵpublishExternalGlobalUtil} from './render3/util/global_utils';
+export {readPatchedData as eReadPatchedData} from './render3/context_discovery';
+export {unwrapRNode as ɵunwrapRNode} from './render3/util/view_utils';
+export {HOST as ɵHOST, PARENT as ɵPARENT} from './render3/interfaces/view';
 export {enableProfiling} from './render3/debug/chrome_dev_tools_performance';
 export {
  AfterRenderOptions,
@@ -126,6 +129,7 @@ export {
 } from './animation/interfaces';

 import {global} from './util/global';
+
 if (typeof ngDevMode !== 'undefined' && ngDevMode) {
  // This helper is to give a reasonable error message to people upgrading to v9 that have not yet
  // installed `@angular/localize` in their app.

diff --git a/packages/core/src/render3/instructions/projection.ts b/packages/core/src/render3/instructions/projection.ts
@@ -11,6 +11,7 @@ import {newArray} from '../../util/array_utils';
 import {assertLContainer, assertTNode} from '../assert';
 import {ComponentTemplate} from '../interfaces/definition';
 import {TAttributes, TElementNode, TNode, TNodeType} from '../interfaces/node';
+import {ViewEncapsulation} from '../../metadata/view';
 import {ProjectionSlots} from '../interfaces/projection';
 import {
  DECLARATION_COMPONENT_VIEW,
@@ -32,6 +33,7 @@ import {addLViewToLContainer} from '../view/container';
 import {createAndRenderEmbeddedLView, shouldAddViewToDom} from '../view_manipulation';

 import {declareNoDirectiveHostTemplate} from './template';
+import {getDeclarationComponentDef} from '../../render3/instructions/element_validation';

 /**
 * Checks a given node against matching projection slots and returns the
@@ -94,7 +96,24 @@ export function matchingProjectionSlotIndex(
 * @codeGenApi
 */
 export function ɵɵprojectionDef(projectionSlots?: ProjectionSlots): void {
-  const componentNode = getLView()[DECLARATION_COMPONENT_VIEW][T_HOST] as TElementNode;
+  const lView = getLView();
+  const declarationComponentView = lView[DECLARATION_COMPONENT_VIEW];
+  const componentNode = declarationComponentView[T_HOST] as TElementNode;
+
+  // Check if this is an IsolatedShadowDom component
+  // The component instance is stored in CONTEXT
+  const componentDef = getDeclarationComponentDef(declarationComponentView);
+
+  if (componentDef?.encapsulation === ViewEncapsulation.ExperimentalIsolatedShadowDom) {
+    if (typeof ngDevMode !== 'undefined' && ngDevMode) {
+      throw new Error(
+        `ng-content projection is not supported with ViewEncapsulation.IsolatedShadowDom. ` +
+          `Use native <slot> elements instead. Content will remain in the light DOM and be projected via slots.`,
+      );
+    }
+    // Don't setup projection for IsolatedShadowDom
+    return;
+  }

  if (!componentNode.projection) {
    // If no explicit projection slots are defined, fall back to a single

diff --git a/packages/core/test/acceptance/renderer_factory_spec.ts b/packages/core/test/acceptance/renderer_factory_spec.ts
@@ -23,6 +23,7 @@ import {
  ɵDomRendererFactory2 as DomRendererFactory2,
  EventManager,
  ɵSharedStylesHost,
+  ɵStyleScopeService as StyleScopeService,
 } from '@angular/platform-browser';
 import {isBrowser, isNode} from '@angular/private/testing';
 import {expect} from '@angular/private/testing/matchers';
@@ -396,6 +397,7 @@ function getRendererFactory2(document: Document): RendererFactory2 {
  const fakeNgZone: NgZone = new NoopNgZone();
  const eventManager = new EventManager([], fakeNgZone);
  const appId = 'app-id';
+  const styleScopeService = new StyleScopeService();
  const rendererFactory = new DomRendererFactory2(
    eventManager,
    new ɵSharedStylesHost(document, appId),
@@ -404,6 +406,8 @@ function getRendererFactory2(document: Document): RendererFactory2 {
    document,
    fakeNgZone,
    null,
+    null, // tracingService
+    styleScopeService,
  );
  const origCreateRenderer = rendererFactory.createRenderer;
  rendererFactory.createRenderer = function (element: any, type: RendererType2 | null) {

diff --git a/packages/core/test/bundling/animations-standalone/bundle.golden_symbols.json b/packages/core/test/bundling/animations-standalone/bundle.golden_symbols.json
@@ -132,6 +132,7 @@
      "InjectionToken",
      "Injector",
      "InputFlags",
+      "IsolatedStyleScopeService",
      "KeyEventsPlugin",
      "LEAVE_CLASSNAME",
      "LEAVE_TOKEN",
@@ -508,6 +509,7 @@
      "getInsertInFrontOfRNode",
      "getInsertInFrontOfRNodeWithNoI18n",
      "getLView",
+      "getLViewById",
      "getLViewParent",
      "getNameOnlyMarkerIndex",
      "getNamespace",
@@ -742,6 +744,7 @@
      "providerToRecord",
      "publishSignalConfiguration",
      "queueEnterAnimations",
+      "readPatchedData",
      "refreshContentQueries",
      "refreshView",
      "registerFailed",

diff --git a/packages/core/test/bundling/create_component/bundle.golden_symbols.json b/packages/core/test/bundling/create_component/bundle.golden_symbols.json
@@ -98,6 +98,7 @@
      "InjectionToken",
      "Injector",
      "InputFlags",
+      "IsolatedStyleScopeService",
      "KeyEventsPlugin",
      "LOCALE_ID",
      "LOCALE_ID",
@@ -406,6 +407,7 @@
      "getInsertInFrontOfRNode",
      "getInsertInFrontOfRNodeWithNoI18n",
      "getLView",
+      "getLViewById",
      "getLViewParent",
      "getNativeByIndex",
      "getNativeByTNode",
@@ -588,6 +590,7 @@
      "providerToRecord",
      "publishSignalConfiguration",
      "queueEnterAnimations",
+      "readPatchedData",
      "refreshContentQueries",
      "refreshView",
      "registerHostBindingOpCodes",

diff --git a/packages/core/test/bundling/defer/bundle.golden_symbols.json b/packages/core/test/bundling/defer/bundle.golden_symbols.json
@@ -24,6 +24,7 @@
      "EventManagerPlugin",
      "HOST_ATTR",
      "INTERNAL_BROWSER_PLATFORM_PROVIDERS",
+      "IsolatedStyleScopeService",
      "KeyEventsPlugin",
      "MODIFIER_KEYS",
      "MODIFIER_KEY_GETTERS",
@@ -456,6 +457,7 @@
      "getInsertInFrontOfRNodeWithNoI18n",
      "getLDeferBlockDetails",
      "getLView",
+      "getLViewById",
      "getLViewParent",
      "getLoadingBlockAfter",
      "getMinimumDurationForState",
@@ -644,6 +646,7 @@
      "providerToRecord",
      "publishSignalConfiguration",
      "queueEnterAnimations",
+      "readPatchedData",
      "refreshContentQueries",
      "refreshView",
      "registerHostBindingOpCodes",

diff --git a/packages/core/test/bundling/forms_reactive/bundle.golden_symbols.json b/packages/core/test/bundling/forms_reactive/bundle.golden_symbols.json
@@ -133,6 +133,7 @@
      "InjectionToken",
      "Injector",
      "InputFlags",
+      "IsolatedStyleScopeService",
      "IterableChangeRecord_",
      "IterableDiffers",
      "KeyEventsPlugin",
@@ -574,6 +575,7 @@
      "getInsertInFrontOfRNode",
      "getInsertInFrontOfRNodeWithNoI18n",
      "getLView",
+      "getLViewById",
      "getLViewParent",
      "getNameOnlyMarkerIndex",
      "getNamespace",
@@ -859,6 +861,7 @@
      "providersResolver",
      "publishSignalConfiguration",
      "queueEnterAnimations",
+      "readPatchedData",
      "readableStreamLikeToAsyncGenerator",
      "refreshContentQueries",
      "refreshView",

diff --git a/packages/core/test/bundling/forms_template_driven/bundle.golden_symbols.json b/packages/core/test/bundling/forms_template_driven/bundle.golden_symbols.json
@@ -127,6 +127,7 @@
      "InjectionToken",
      "Injector",
      "InputFlags",
+      "IsolatedStyleScopeService",
      "IterableChangeRecord_",
      "IterableDiffers",
      "KeyEventsPlugin",
@@ -575,6 +576,7 @@
      "getInsertInFrontOfRNode",
      "getInsertInFrontOfRNodeWithNoI18n",
      "getLView",
+      "getLViewById",
      "getLViewParent",
      "getNameOnlyMarkerIndex",
      "getNamespace",
@@ -857,6 +859,7 @@
      "providersResolver",
      "publishSignalConfiguration",
      "queueEnterAnimations",
+      "readPatchedData",
      "readableStreamLikeToAsyncGenerator",
      "refreshContentQueries",
      "refreshView",

diff --git a/packages/core/test/bundling/hydration/bundle.golden_symbols.json b/packages/core/test/bundling/hydration/bundle.golden_symbols.json
@@ -115,6 +115,7 @@
      "InjectionToken",
      "Injector",
      "InputFlags",
+      "IsolatedStyleScopeService",
      "JSON_CONTENT_TYPE",
      "KeyEventsPlugin",
      "LOCALE_ID",
@@ -477,6 +478,7 @@
      "getInsertInFrontOfRNodeWithNoI18n",
      "getLNodeForHydration",
      "getLView",
+      "getLViewById",
      "getLViewParent",
      "getNamespace",
      "getNativeByTNode",
@@ -683,6 +685,7 @@
      "providerToRecord",
      "publishSignalConfiguration",
      "queueEnterAnimations",
+      "readPatchedData",
      "readableStreamLikeToAsyncGenerator",
      "refreshContentQueries",
      "refreshView",

diff --git a/packages/core/test/bundling/router/bundle.golden_symbols.json b/packages/core/test/bundling/router/bundle.golden_symbols.json
@@ -131,6 +131,7 @@
      "InjectionToken",
      "Injector",
      "InputFlags",
+      "IsolatedStyleScopeService",
      "ItemComponent",
      "KeyEventsPlugin",
      "LOCALE_ID",
@@ -665,6 +666,7 @@
      "getInsertInFrontOfRNode",
      "getInsertInFrontOfRNodeWithNoI18n",
      "getLView",
+      "getLViewById",
      "getLViewParent",
      "getNameOnlyMarkerIndex",
      "getNamespace",
@@ -967,6 +969,7 @@
      "providerToRecord",
      "publishSignalConfiguration",
      "queueEnterAnimations",
+      "readPatchedData",
      "readableStreamLikeToAsyncGenerator",
      "recognize",
      "recognize",
-Original file line number
+Diff line change
@@ -1,5 +1,5 @@
     {
-      "dist/main.js": 153915,
-      "dist/polyfills.js": 34023,
-      "dist/open-close.component-[hash].js": 1190
+      "dist/main.js": 159053,
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            JeanMeche
  

      

      

      


        Dec 1, 2025


      
    

  


        
      
  
  
  
    

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      Since this is quite an increase, we should investigate better tree shaking when the feature isn't used
    
  
  



    

        
      
  
  
    
  
  
  
    
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            ryan-bendel
  

      

      

      


        Dec 1, 2025


      
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      I shall take a look @JeanMeche - but i am struggling to run the integration tests locally (i bumped all the size.json from the output in the gh test runner output),
I get:
ERROR  Failed to switch pnpm to v10.23.0. Looks like pnpm CLI is missing at "/var/folders/kj/cqmyhbyx0zv7mrtvpdlj19dw0000gp/T/ng-integration-test7nTJJM/tmp-env-0/Library/pnpm/.tools/pnpm/10.23.0/bin" or is incorrect
spawnSync /var/folders/kj/cqmyhbyx0zv7mrtvpdlj19dw0000gp/T/ng-integration-test7nTJJM/tmp-env-0/Library/pnpm/.tools/pnpm/10.23.0/bin/pnpm ENOENT
Command failed: `pnpm install`

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+      "dist/polyfills.js": 35677,
+      "dist/open-close.component-[hash].js": 1131
     }