[LTS fix] only return empty href when LinkTo href generation throws error

packages/@ember/-internals/glimmer/tests/integration/components/link-to/rendering-angle-test.js

@@ -141,7 +141,7 @@ moduleFor(
 
       this.assertComponentElement(this.element.firstChild, {
         tagName: 'a',
-        attrs: { href: null },
+        attrs: { href: '#/' },
         content: 'Go to Index',
       });
     }
@@ -169,10 +169,24 @@ moduleFor(
       return this.owner.resolveRegistration('router:main');
     }
 
-    ['@test should be able to be inserted in DOM when router is setup but not started']() {
+    ['@test should be able to be inserted in DOM when initial transition not started']() {
       this.render(`<LinkTo @route="dynamicWithChild.child">Link</LinkTo>`);
       this.assertComponentElement(this.element.firstChild, {
         tagName: 'a',
+        attrs: {
+          href: null,
+        },
+        content: 'Link',
+      });
+    }
+
+    ['@test should be able to be inserted in DOM with valid href when complete models are passed even if initial transition is not started']() {
+      this.render(`<LinkTo @route="dynamicWithChild.child" @model="1">Link</LinkTo>`);
+      this.assertComponentElement(this.element.firstChild, {
+        tagName: 'a',
+        attrs: {
+          href: '/dynamic-with-child/1/child',
+        },
         content: 'Link',
       });
     }

packages/@ember/-internals/routing/lib/services/routing.ts

@@ -52,25 +52,32 @@ export default class RoutingService extends Service {
     this.router._prepareQueryParams(routeName, models, queryParams);
   }
 
-  generateURL(routeName: string, models: {}[], queryParams: {}) {
-    let router = this.router;
-    // Return early when transition has not started, when rendering in tests without visit(),
-    // we cannot infer the route context which <LinkTo/> needs be aware of
-    if (!router._initialTransitionStarted) {
-      return;
-    }
-
+  _generateURL(routeName: string, models: {}[], queryParams: {}) {
     let visibleQueryParams = {};
     if (queryParams) {
       assign(visibleQueryParams, queryParams);
       this.normalizeQueryParams(routeName, models, visibleQueryParams as QueryParam);
     }
 
-    return router.generate(routeName, ...models, {
+    return this.router.generate(routeName, ...models, {
       queryParams: visibleQueryParams,
     });
   }
 
+  generateURL(routeName: string, models: {}[], queryParams: {}) {
+    if (this.router._initialTransitionStarted) {
+      return this._generateURL(routeName, models, queryParams);
+    } else {
+      // Swallow error when transition has not started.
+      // When rendering in tests without visit(), we cannot infer the route context which <LinkTo/> needs be aware of
+      try {
+        return this._generateURL(routeName, models, queryParams);
+      } catch (_e) {
+        return;
+      }
+    }
+  }
+
   isActiveForRoute(
     contexts: {}[],
     queryParams: QueryParam | undefined,