fix(ivy): incorrectly validating html foreign objects inside svg (#34178)

Fixes ngtsc incorrectly logging an unknown element diagnostic for HTML elements that are inside an SVG `foreignObject` with the `xhtml` namespace.

Fixes #34171.

PR Close #34178

packages/compiler-cli/src/ngtsc/typecheck/src/dom.ts

@@ -14,6 +14,7 @@ import {ErrorCode} from '../../diagnostics';
 import {TcbSourceResolver, makeTemplateDiagnostic} from './diagnostics';
 
 const REGISTRY = new DomElementSchemaRegistry();
+const REMOVE_XHTML_REGEX = /^:xhtml:/;
 
 /**
  * Checks every non-Angular element/property processed in a template and potentially produces
@@ -69,15 +70,20 @@ export class RegistryDomSchemaChecker implements DomSchemaChecker {
   constructor(private resolver: TcbSourceResolver) {}
 
   checkElement(id: string, element: TmplAstElement, schemas: SchemaMetadata[]): void {
-    if (!REGISTRY.hasElement(element.name, schemas)) {
+    // HTML elements inside an SVG `foreignObject` are declared in the `xhtml` namespace.
+    // We need to strip it before handing it over to the registry because all HTML tag names
+    // in the registry are without a namespace.
+    const name = element.name.replace(REMOVE_XHTML_REGEX, '');
+
+    if (!REGISTRY.hasElement(name, schemas)) {
       const mapping = this.resolver.getSourceMapping(id);
 
-      let errorMsg = `'${element.name}' is not a known element:\n`;
+      let errorMsg = `'${name}' is not a known element:\n`;
       errorMsg +=
-          `1. If '${element.name}' is an Angular component, then verify that it is part of this module.\n`;
-      if (element.name.indexOf('-') > -1) {
+          `1. If '${name}' is an Angular component, then verify that it is part of this module.\n`;
+      if (name.indexOf('-') > -1) {
         errorMsg +=
-            `2. If '${element.name}' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message.`;
+            `2. If '${name}' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message.`;
       } else {
         errorMsg +=
             `2. To allow any element add 'NO_ERRORS_SCHEMA' to the '@NgModule.schemas' of this component.`;

packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts

@@ -1362,6 +1362,55 @@ export declare class AnimationEvent {
         const diags = env.driveDiagnostics();
         expect(diags).toEqual([]);
       });
+
+      it('should allow HTML elements inside SVG foreignObject', () => {
+        env.write('test.ts', `
+        import {Component, NgModule} from '@angular/core';
+        @Component({
+          selector: 'blah',
+          template: \`
+            <svg>
+              <svg:foreignObject>
+                <xhtml:div>Hello</xhtml:div>
+              </svg:foreignObject>
+            </svg>
+          \`,
+        })
+        export class FooCmp {}
+        @NgModule({
+          declarations: [FooCmp],
+        })
+        export class FooModule {}
+      `);
+        const diags = env.driveDiagnostics();
+        expect(diags.length).toBe(0);
+      });
+
+      it('should check for unknown elements inside an SVG foreignObject', () => {
+        env.write('test.ts', `
+        import {Component, NgModule} from '@angular/core';
+        @Component({
+          selector: 'blah',
+          template: \`
+            <svg>
+              <svg:foreignObject>
+                <xhtml:foo>Hello</xhtml:foo>
+              </svg:foreignObject>
+            </svg>
+          \`,
+        })
+        export class FooCmp {}
+        @NgModule({
+          declarations: [FooCmp],
+        })
+        export class FooModule {}
+      `);
+        const diags = env.driveDiagnostics();
+        expect(diags.length).toBe(1);
+        expect(diags[0].messageText).toBe(`'foo' is not a known element:
+1. If 'foo' is an Angular component, then verify that it is part of this module.
+2. To allow any element add 'NO_ERRORS_SCHEMA' to the '@NgModule.schemas' of this component.`);
+      });
     });
 
     // Test both sync and async compilations, see https://github.com/angular/angular/issues/32538

packages/core/test/acceptance/ng_module_spec.ts

@@ -311,5 +311,30 @@ describe('NgModule', () => {
       }).not.toThrow();
     });
 
+    it('should not throw for HTML elements inside an SVG foreignObject', () => {
+      @Component({
+        template: `
+          <svg>
+            <svg:foreignObject>
+              <xhtml:div>Hello</xhtml:div>
+            </svg:foreignObject>
+          </svg>
+        `,
+      })
+      class MyComp {
+      }
+
+      @NgModule({declarations: [MyComp]})
+      class MyModule {
+      }
+
+      TestBed.configureTestingModule({imports: [MyModule]});
+
+      expect(() => {
+        const fixture = TestBed.createComponent(MyComp);
+        fixture.detectChanges();
+      }).not.toThrow();
+    });
+
   });
 });