fix(compiler): avoid conflicts between HMR code and local symbols (#61550)

crisbeto · thePunderWoman · commit 44bb328eaea0 · 2025-05-21T12:25:27.000Z
Currently we construct the HMR replacement URL inline by calling into the native `URL` constructor. This can cause conflicts with user code that defines a symbol called `URL`. These changes resolve the issue by moving the URL construction into a separate function. This has a secondary benefit of making the generated code easier to follow and allowing us to update the URL without changing the compiled code. Fixes #61517. PR Close #61550
diff --git a/packages/compiler-cli/test/ngtsc/hmr_spec.ts b/packages/compiler-cli/test/ngtsc/hmr_spec.ts
@@ -115,7 +115,7 @@ runInEachFileSystem(() => {
       expect(jsContents).toContain('const id = "test.ts%40Cmp";');
       expect(jsContents).toContain('function Cmp_HmrLoad(t) {');
       expect(jsContents).toContain(
-        'import(/* @vite-ignore */\nnew URL("./@ng/component?c=" + id + "&t=" + encodeURIComponent(t), import.meta.url).href)',
+        'import(/* @vite-ignore */\ni0.ɵɵgetReplaceMetadataURL(id, t, import.meta.url)',
       );
       expect(jsContents).toContain(
         ').then(m => m.default && i0.ɵɵreplaceMetadata(Cmp, m.default, [i0], ' +
@@ -183,7 +183,7 @@ runInEachFileSystem(() => {
       expect(jsContents).toContain('const id = "test.ts%40Cmp";');
       expect(jsContents).toContain('function Cmp_HmrLoad(t) {');
       expect(jsContents).toContain(
-        'import(/* @vite-ignore */\nnew URL("./@ng/component?c=" + id + "&t=" + encodeURIComponent(t), import.meta.url).href)',
+        'import(/* @vite-ignore */\ni0.ɵɵgetReplaceMetadataURL(id, t, import.meta.url)',
       );
       expect(jsContents).toContain(
         ').then(m => m.default && i0.ɵɵreplaceMetadata(Cmp, m.default, [i0, i1], ' +
diff --git a/packages/compiler/src/render3/r3_hmr_compiler.ts b/packages/compiler/src/render3/r3_hmr_compiler.ts
@@ -80,21 +80,17 @@ export function compileHmrInitializer(meta: R3HmrMetadata): o.Expression {
   // (m) => m.default && ɵɵreplaceMetadata(...)
   const replaceCallback = o.arrowFn([new o.FnParam(moduleName)], defaultRead.and(replaceCall));
 
-  // '<url>?c=' + id + '&t=' + encodeURIComponent(t)
-  const urlValue = o
-    .literal(`./@ng/component?c=`)
-    .plus(o.variable(idName))
-    .plus(o.literal('&t='))
-    .plus(o.variable('encodeURIComponent').callFn([o.variable(timestampName)]));
-
-  // import.meta.url
-  const urlBase = o.variable('import').prop('meta').prop('url');
-
-  // new URL(urlValue, urlBase).href
-  const urlHref = new o.InstantiateExpr(o.variable('URL'), [urlValue, urlBase]).prop('href');
+  // getReplaceMetadataURL(id, timestamp, import.meta.url)
+  const url = o
+    .importExpr(R3.getReplaceMetadataURL)
+    .callFn([
+      o.variable(idName),
+      o.variable(timestampName),
+      o.variable('import').prop('meta').prop('url'),
+    ]);
 
   // function Cmp_HmrLoad(t) {
-  //   import(/* @vite-ignore */ urlHref).then((m) => m.default && replaceMetadata(...));
+  //   import(/* @vite-ignore */ url).then((m) => m.default && replaceMetadata(...));
   // }
   const importCallback = new o.DeclareFunctionStmt(
     importCallbackName,
@@ -103,7 +99,7 @@ export function compileHmrInitializer(meta: R3HmrMetadata): o.Expression {
       // The vite-ignore special comment is required to prevent Vite from generating a superfluous
       // warning for each usage within the development code. If Vite provides a method to
       // programmatically avoid this warning in the future, this added comment can be removed here.
-      new o.DynamicImportExpr(urlHref, null, '@vite-ignore')
+      new o.DynamicImportExpr(url, null, '@vite-ignore')
         .prop('then')
         .callFn([replaceCallback])
         .toStmt(),
diff --git a/packages/compiler/src/render3/r3_identifiers.ts b/packages/compiler/src/render3/r3_identifiers.ts
@@ -411,6 +411,10 @@ export class Identifiers {
   static resolveForwardRef: o.ExternalReference = {name: 'resolveForwardRef', moduleName: CORE};
 
   static replaceMetadata: o.ExternalReference = {name: 'ɵɵreplaceMetadata', moduleName: CORE};
+  static getReplaceMetadataURL: o.ExternalReference = {
+    name: 'ɵɵgetReplaceMetadataURL',
+    moduleName: CORE,
+  };
 
   static ɵɵdefineInjectable: o.ExternalReference = {name: 'ɵɵdefineInjectable', moduleName: CORE};
   static declareInjectable: o.ExternalReference = {name: 'ɵɵngDeclareInjectable', moduleName: CORE};
diff --git a/packages/core/src/core_render3_private_export.ts b/packages/core/src/core_render3_private_export.ts
@@ -247,6 +247,7 @@ export {
   ɵɵstoreLet,
   ɵɵreadContextLet,
   ɵɵreplaceMetadata,
+  ɵɵgetReplaceMetadataURL,
   ɵɵattachSourceLocations,
 } from './render3/index';
 export {CONTAINER_HEADER_OFFSET as ɵCONTAINER_HEADER_OFFSET} from './render3/interfaces/container';
diff --git a/packages/core/src/render3/hmr.ts b/packages/core/src/render3/hmr.ts
@@ -52,6 +52,19 @@ type ImportMetaExtended = ImportMeta & {
   };
 };
 
+/**
+ * Gets the URL from which the client will fetch a new version of a component's metadata so it
+ * can be replaced during hot module reloading.
+ * @param id Unique ID for the component, generated during compile time.
+ * @param timestamp Time at which the request happened.
+ * @param base Base URL against which to resolve relative paths.
+ * @codeGenApi
+ */
+export function ɵɵgetReplaceMetadataURL(id: string, timestamp: string, base: string): string {
+  const url = `./@ng/component?c=${id}&t=${encodeURIComponent(timestamp)}`;
+  return new URL(url, base).href;
+}
+
 /**
  * Replaces the metadata of a component type and re-renders all live instances of the component.
  * @param type Class whose metadata will be replaced.
diff --git a/packages/core/src/render3/index.ts b/packages/core/src/render3/index.ts
@@ -217,7 +217,7 @@ export {ɵɵresolveBody, ɵɵresolveDocument, ɵɵresolveWindow} from './util/mi
 export {ɵɵtemplateRefExtractor} from './view_engine_compatibility_prebound';
 export {ɵɵgetComponentDepsFactory} from './local_compilation';
 export {ɵsetClassDebugInfo} from './debug/set_debug_info';
-export {ɵɵreplaceMetadata} from './hmr';
+export {ɵɵreplaceMetadata, ɵɵgetReplaceMetadataURL} from './hmr';
 
 export {store} from './util/view_utils';
 
diff --git a/packages/core/src/render3/jit/environment.ts b/packages/core/src/render3/jit/environment.ts
@@ -217,4 +217,5 @@ export const angularCoreEnv: {[name: string]: unknown} = (() => ({
   'ɵɵtwoWayListener': r3.ɵɵtwoWayListener,
 
   'ɵɵreplaceMetadata': r3.ɵɵreplaceMetadata,
+  'ɵɵgetReplaceMetadataURL': r3.ɵɵgetReplaceMetadataURL,
 }))();
