fix(@angular/ssr): properly manage catch-all routes with base href

This fix ensures that catch-all routes (e.g., wildcard routes like `**`) are handled correctly when a base href is configured in an Angular SSR application.

Closes #29397

Author: alan-agius4

packages/angular/ssr/src/routes/ng-routes.ts

@@ -583,13 +583,13 @@ export async function getRoutesFromAngularRouterConfig(
 
       if (serverConfigRouteTree) {
         for (const { route, presentInClientRouter } of serverConfigRouteTree.traverse()) {
-          if (presentInClientRouter || route === '**') {
+          if (presentInClientRouter || route.endsWith('/**')) {
             // Skip if matched or it's the catch-all route.
             continue;
           }
 
           errors.push(
-            `The '${route}' server route does not match any routes defined in the Angular ` +
+            `The '${stripLeadingSlash(route)}' server route does not match any routes defined in the Angular ` +
               `routing configuration (typically provided as a part of the 'provideRouter' call). ` +
               'Please make sure that the mentioned server route is present in the Angular routing configuration.',
           );

packages/angular/ssr/src/routes/route-tree.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { stripTrailingSlash } from '../utils/url';
+import { addLeadingSlash, stripLeadingSlash, stripTrailingSlash } from '../utils/url';
 import { RenderMode } from './route-config';
 
 /**
@@ -155,7 +155,7 @@ export class RouteTree<AdditionalMetadata extends Record<string, unknown> = {}>
     // At the leaf node, store the full route and its associated metadata
     node.metadata = {
       ...metadata,
-      route: normalizedSegments.join('/'),
+      route: addLeadingSlash(normalizedSegments.join('/')),
     };
 
     node.insertionIndex = this.insertionIndexCounter++;
@@ -230,7 +230,7 @@ export class RouteTree<AdditionalMetadata extends Record<string, unknown> = {}>
    * @returns An array of path segments.
    */
   private getPathSegments(route: string): string[] {
-    return stripTrailingSlash(route).split('/');
+    return stripLeadingSlash(stripTrailingSlash(route)).split('/');
   }
 
   /**
@@ -253,11 +253,7 @@ export class RouteTree<AdditionalMetadata extends Record<string, unknown> = {}>
 
     // If there are no remaining segments and the node has metadata, return this node
     if (!remainingSegments?.length) {
-      if (metadata) {
-        return node;
-      }
-
-      return;
+      return metadata ? node : node.children.get('**');
     }
 
     // If the node has no children, end the traversal

packages/angular/ssr/test/routes/route-tree_spec.ts

@@ -150,7 +150,7 @@ describe('RouteTree', () => {
   describe('match', () => {
     it('should handle empty routes', () => {
       routeTree.insert('', { renderMode: RenderMode.Server });
-      expect(routeTree.match('')).toEqual({ route: '', renderMode: RenderMode.Server });
+      expect(routeTree.match('')).toEqual({ route: '/', renderMode: RenderMode.Server });
     });
 
     it('should insert and match basic routes', () => {
@@ -274,5 +274,13 @@ describe('RouteTree', () => {
         renderMode: RenderMode.Server,
       });
     });
+
+    it('should correctly match catch-all segments with a prefix', () => {
+      routeTree.insert('/de/**', { renderMode: RenderMode.Server });
+      expect(routeTree.match('/de')).toEqual({
+        route: '/de/**',
+        renderMode: RenderMode.Server,
+      });
+    });
   });
 });