angular · leonsenft · Aug 21, 2026 · Aug 20, 2026
diff --git a/goldens/public-api/compiler-cli/compiler_options.api.md b/goldens/public-api/compiler-cli/compiler_options.api.md
@@ -7,6 +7,7 @@
 // @public
 export interface BazelAndG3Options {
     annotateForClosureCompiler?: boolean;
+    enableTemplateSourceLocations?: boolean;
     _experimentalAllowEmitDeclarationOnly?: boolean;
     generateDeepReexports?: boolean;
     generateExtraImportsInLocalMode?: boolean;

diff --git a/packages/compiler-cli/linker/src/file_linker/partial_linkers/partial_component_linker_1.ts b/packages/compiler-cli/linker/src/file_linker/partial_linkers/partial_component_linker_1.ts
@@ -255,6 +255,7 @@ export class PartialComponentLinkerVersion1<
       declarations,
       hasDirectiveDependencies: !baseMeta.isStandalone || hasDirectiveDependencies,
       foreignImports: null,
+      enableTemplateSourceLocations: false,
     };
   }
 

diff --git a/packages/compiler-cli/src/ngtsc/annotations/component/src/handler.ts b/packages/compiler-cli/src/ngtsc/annotations/component/src/handler.ts
@@ -291,6 +291,7 @@ export class ComponentDecoratorHandler implements DecoratorHandler<
     private readonly enableSelectorless: boolean,
     private readonly emitDeclarationOnly: boolean,
     private readonly legacyOptionalChaining: boolean,
+    private readonly enableTemplateSourceLocations: boolean,
   ) {
     this.extractTemplateOptions = {
       enableI18nLegacyMessageIdFormat: this.enableI18nLegacyMessageIdFormat,
@@ -1024,6 +1025,7 @@ export class ComponentDecoratorHandler implements DecoratorHandler<
           rawImports: rawImports !== null ? new o.WrappedNodeExpr(rawImports) : undefined,
           relativeTemplatePath,
           foreignImports: null,
+          enableTemplateSourceLocations: this.enableTemplateSourceLocations,
         },
         typeCheckMeta: extractDirectiveTypeCheckMeta(node, inputs, this.reflector),
         classMetadata: this.includeClassMetadata

diff --git a/packages/compiler-cli/src/ngtsc/annotations/component/test/component_spec.ts b/packages/compiler-cli/src/ngtsc/annotations/component/test/component_spec.ts
@@ -164,6 +164,7 @@ function setup(
     /* enableSelectorless */ false,
     /* emitDeclarationOnly */ false,
     /* enableInlineStyles */ true,
+    /* enableTemplateSourceLocations */ false,
   );
   return {reflectionHost, handler, resourceLoader, metaRegistry};
 }

diff --git a/packages/compiler-cli/src/ngtsc/core/api/src/public_options.ts b/packages/compiler-cli/src/ngtsc/core/api/src/public_options.ts
@@ -340,11 +340,18 @@ export interface BazelAndG3Options {
   _experimentalAllowEmitDeclarationOnly?: boolean;
 
   /**
-   * Whether to follow the Javascript optional chaining specs: returning `undefined` instead of `null` for null-safe navigation operations.
+   * Whether to follow the Javascript optional chaining specs: returning `undefined` instead of
+   * `null` for null-safe navigation operations.
    *
    * Defaults to `false`.
    */
   legacyOptionalChaining?: boolean;
+
+  /**
+   * Whether to generate additional code that adds the source location
+   * of elements to the DOM as an attribute.
+   */
+  enableTemplateSourceLocations?: boolean;
 }
 
 /**

diff --git a/packages/compiler-cli/src/ngtsc/core/src/compiler.ts b/packages/compiler-cli/src/ngtsc/core/src/compiler.ts
@@ -397,6 +397,7 @@ export class NgCompiler {
   private readonly implicitStandaloneValue: boolean;
   private readonly enableSelectorless: boolean;
   private readonly emitDeclarationOnly: boolean;
+  private readonly enableTemplateSourceLocations: boolean;
 
   /**
    * `NgCompiler` can be reused for multiple compilations (for resource-only changes), and each
@@ -472,6 +473,7 @@ export class NgCompiler {
       this.angularCoreVersion === null ||
       coreVersionSupportsFeature(this.angularCoreVersion, '>= 18.1.0');
     this.enableSelectorless = options['_enableSelectorless'] ?? false;
+    this.enableTemplateSourceLocations = options['enableTemplateSourceLocations'] ?? false;
     this.emitDeclarationOnly =
       !!options.emitDeclarationOnly && !!options._experimentalAllowEmitDeclarationOnly;
     // Standalone by default is enabled since v19. We need to toggle it here,
@@ -1549,6 +1551,7 @@ export class NgCompiler {
         this.enableSelectorless,
         this.emitDeclarationOnly,
         this.options.legacyOptionalChaining ?? LEGACY_OPTIONAL_CHAINING_DEFAULT,
+        this.enableTemplateSourceLocations,
       ),
 
       // TODO(alxhub): understand why the cast here is necessary (something to do with `null`

diff --git a/packages/compiler-cli/test/ngtsc/attach_source_location_spec.ts b/packages/compiler-cli/test/ngtsc/attach_source_location_spec.ts
@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import {setEnableTemplateSourceLocations} from '@angular/compiler';
 import {runInEachFileSystem} from '../../src/ngtsc/file_system/testing';
 import {loadStandardTestFiles} from '../../src/ngtsc/testing';
 import {NgtscTestEnvironment} from './env';
@@ -18,16 +17,33 @@ runInEachFileSystem(() => {
     let env!: NgtscTestEnvironment;
 
     beforeEach(() => {
-      setEnableTemplateSourceLocations(true);
       env = NgtscTestEnvironment.setup(testFiles);
-      env.tsconfig();
     });
 
-    afterEach(() => {
-      setEnableTemplateSourceLocations(false);
+    it('should not attach template source locations by default', () => {
+      env.tsconfig();
+      env.write(
+        `test.ts`,
+        `
+          import {Component} from '@angular/core';
+
+          @Component({
+            template: \`
+              <div><span>
+                <strong>Hello</strong>
+              </span></div>
+            \`,
+          })
+          class Comp {}
+         `,
+      );
+      env.driveMain();
+      const content = env.getContents('test.js');
+      expect(content).not.toContain('ɵɵattachSourceLocations');
     });
 
     it('should attach the source location in an inline template', () => {
+      env.tsconfig({enableTemplateSourceLocations: true});
       env.write(
         `test.ts`,
         `
@@ -52,6 +68,7 @@ runInEachFileSystem(() => {
     });
 
     it('should attach the source location in an external template', () => {
+      env.tsconfig({enableTemplateSourceLocations: true});
       env.write(
         'test.html',
         `
@@ -79,6 +96,7 @@ runInEachFileSystem(() => {
     });
 
     it('should attach the source location to structural directives', () => {
+      env.tsconfig({enableTemplateSourceLocations: true});
       env.write(
         `test.ts`,
         `
@@ -107,6 +125,7 @@ runInEachFileSystem(() => {
     });
 
     it('should not attach the source location to ng-container', () => {
+      env.tsconfig({enableTemplateSourceLocations: true});
       env.write(
         `test.ts`,
         `

diff --git a/packages/compiler/src/compiler.ts b/packages/compiler/src/compiler.ts
@@ -265,7 +265,6 @@ export {outputAst};
 export {CompilerFacadeImpl} from './jit_compiler_facade';
 export {FactoryTarget} from './compiler_facade_interface';
 export {QueryFlags} from './render3/view/query_generation';
-export {setEnableTemplateSourceLocations} from './render3/view/config';
 
 export * from './typecheck/api';
 export * from './typecheck/host_bindings';

diff --git a/packages/compiler/src/jit_compiler_facade.ts b/packages/compiler/src/jit_compiler_facade.ts
@@ -363,6 +363,7 @@ export class CompilerFacadeImpl implements CompilerFacade {
       i18nUseExternalIds: true,
       relativeTemplatePath: null,
       foreignImports: null,
+      enableTemplateSourceLocations: false,
     };
     const jitExpressionSourceMap = `ng:///${facade.name}.js`;
     return this.compileComponentFromMeta(angularCoreEnv, jitExpressionSourceMap, meta);
@@ -724,6 +725,7 @@ function convertDeclareComponentFacadeToMetadata(
     hasDirectiveDependencies,
     legacyOptionalChaining: decl.legacyOptionalChaining ?? LEGACY_OPTIONAL_CHAINING_DEFAULT,
     foreignImports: null,
+    enableTemplateSourceLocations: false,
   };
 }
 

diff --git a/packages/compiler/src/render3/view/api.ts b/packages/compiler/src/render3/view/api.ts
@@ -310,6 +310,12 @@ export interface R3ComponentMetadata<
    * Foreign components imported by the component.
    */
   foreignImports: R3ForeignComponentMetadata[] | null;
+
+  /**
+   * Whether to generate additional code that adds the source location
+   * of elements to the DOM as an attribute.
+   */
+  enableTemplateSourceLocations?: boolean;
 }
 
 /**
@@ -364,9 +370,7 @@ export interface R3TemplateDependency {
  * A dependency that's used within a component template
  */
 export type R3TemplateDependencyMetadata =
-  | R3DirectiveDependencyMetadata
-  | R3PipeDependencyMetadata
-  | R3NgModuleDependencyMetadata;
+  R3DirectiveDependencyMetadata | R3PipeDependencyMetadata | R3NgModuleDependencyMetadata;
 
 /**
  * Information about a directive that is used in a component template. Only the stable, public

diff --git a/packages/compiler/src/render3/view/compiler.ts b/packages/compiler/src/render3/view/compiler.ts
@@ -27,7 +27,7 @@ import {
   R3HostMetadata,
   R3TemplateDependency,
 } from './api';
-import {getTemplateSourceLocationsEnabled} from './config';
+import {ENABLE_TEMPLATE_SOURCE_LOCATIONS} from './config';
 import {createContentQueriesFunction, createViewQueriesFunction} from './query_generation';
 import {makeBindingParser} from './template';
 import {asLiteral, conditionallyCreateDirectiveBindingLiteral, DefinitionMap} from './util';
@@ -214,7 +214,7 @@ export function compileComponentFromMetadata(
     meta.defer,
     allDeferrableDepsFn,
     meta.relativeTemplatePath,
-    getTemplateSourceLocationsEnabled(),
+    meta.enableTemplateSourceLocations || ENABLE_TEMPLATE_SOURCE_LOCATIONS,
     meta.legacyOptionalChaining,
     meta.foreignImports,
   );

diff --git a/packages/compiler/src/render3/view/config.ts b/packages/compiler/src/render3/view/config.ts
@@ -13,16 +13,4 @@
  * tools enable it via a local change. Any modifications to this flag need to update the
  * internal tooling as well.
  */
-let ENABLE_TEMPLATE_SOURCE_LOCATIONS = false;
-
-/**
- * Utility function to enable source locations. Intended to be used **only** inside unit tests.
- */
-export function setEnableTemplateSourceLocations(value: boolean): void {
-  ENABLE_TEMPLATE_SOURCE_LOCATIONS = value;
-}
-
-/** Gets whether template source locations are enabled. */
-export function getTemplateSourceLocationsEnabled(): boolean {
-  return ENABLE_TEMPLATE_SOURCE_LOCATIONS;
-}
+export const ENABLE_TEMPLATE_SOURCE_LOCATIONS = false;