feat(vue,nuxt): Record default UI spans without Options API (mixins)

dev-packages/e2e-tests/test-applications/nuxt-5/tests/tracing.client.test.ts

@@ -46,10 +46,9 @@ test('sends a navigation root span with a parameterized URL', async ({ page }) =
 });
 
 test('sends component tracking spans when `trackComponents` is enabled', async ({ page }) => {
-  // Nuxt 5 disables the Options API by default (nuxt/nuxt#35791), which turns `app.mixin()` into a
-  // no-op, and that mixin is where the SDK creates every UI span. Flips to passing once component
-  // tracking works without it.
-  test.fail(true, 'Vue tracing is registered through app.mixin(), which needs the Options API');
+  // Nuxt 5 disables the Options API by default (nuxt/nuxt#35791), and component spans only exist
+  // through `app.mixin()`, which that flag turns into a no-op. `vue: { optionsApi: true }` re-enables it.
+  test.fail(true, 'Component tracking (`trackComponents`) needs the Options API');
 
   const spansPromise = collectStreamedSpansUntilSegment(
     'nuxt-5',
@@ -77,10 +76,6 @@ test('sends component tracking spans when `trackComponents` is enabled', async (
 });
 
 test('sends an application render span and a root component span on pageload', async ({ page }) => {
-  // Same root cause as above: no Options API, no `app.mixin()`, no UI spans. Flips to passing once
-  // the root spans stop depending on the mixin.
-  test.fail(true, 'Vue tracing is registered through app.mixin(), which needs the Options API');
-
   const spansPromise = collectStreamedSpansUntilSegment(
     'nuxt-5',
     span => span.name === '/client-error' && getSpanOp(span) === 'pageload',

dev-packages/e2e-tests/test-applications/vue-3/src/router/index.ts

@@ -1,4 +1,5 @@
 import { createRouter, createWebHistory } from 'vue-router';
+import DelayedView from '../views/DelayedView.vue';
 import HomeView from '../views/HomeView.vue';
 
 const router = createRouter({
@@ -8,6 +9,11 @@ const router = createRouter({
       path: '/',
       component: HomeView,
     },
+    {
+      // Loaded eagerly so the only async step on this route is the view's delayed child component.
+      path: '/delayed',
+      component: DelayedView,
+    },
     {
       path: '/about',
       name: 'AboutView',

dev-packages/e2e-tests/test-applications/vue-3/src/views/DelayedView.vue

@@ -0,0 +1,26 @@
+<script setup lang="ts">
+import type { Component } from 'vue';
+import { defineAsyncComponent, h } from 'vue';
+
+// Must stay in sync with `ASYNC_CHILD_DELAY_S` in `tests/performance.test.ts`.
+const ASYNC_CHILD_DELAY_MS = 300;
+
+// A child that mounts a fixed delay after the rest of the page, so tests can prove the
+// `Application Render` span does not wait for late children on either instrumentation path.
+const DelayedChild = defineAsyncComponent(
+  () =>
+    new Promise<Component>(resolve => {
+      setTimeout(
+        () => resolve({ render: () => h('p', { id: 'delayed-child' }, 'Delayed child') }),
+        ASYNC_CHILD_DELAY_MS,
+      );
+    }),
+);
+</script>
+
+<template>
+  <main>
+    <h1>Delayed</h1>
+    <DelayedChild />
+  </main>
+</template>

dev-packages/e2e-tests/test-applications/vue-3/tests/performance.test.ts

@@ -4,6 +4,9 @@ import { collectStreamedSpans, getSpanOp, waitForStreamedSpan } from '@sentry-in
 // Set by the `assert-command` of the `vue-3 (no Options API)` variant
 const OPTIONS_API_DISABLED = process.env.VUE_OPTIONS_API === 'false';
 
+// Must stay in sync with `ASYNC_CHILD_DELAY_MS` in `src/views/DelayedView.vue`.
+const ASYNC_CHILD_DELAY_S = 0.3;
+
 test('sends a pageload span with a parameterized URL', async ({ page }) => {
   const pageloadSpanPromise = waitForStreamedSpan('vue-3', span => {
     return span.is_segment && getSpanOp(span) === 'pageload';
@@ -106,27 +109,25 @@ test('sends a pageload span with a route name as span name if available', async
   });
 });
 
-// The root component is always tracked, even when the route's view is missing from `trackComponents`.
-// The root itself mounts synchronously on both routes (`app.mount()` does not wait for the router).
-// What differs on `/components` is that its view arrives through a dynamic `import()`, so the
-// async-loaded components must join the same pageload while `Application Render` is still open.
+// The root component is always tracked, and the `app.mount()` wrap records the root spans when
+// the Options API is disabled, so both variants expect them. The tracked component spans on
+// `/components` still need the Options API, so the disabled variant expects the root spans only.
 [
   {
     route: '/',
     routeDescription: 'a route with a synchronously mounted component',
     // `HomeView` is missing from `trackComponents`, so the root spans are the only UI spans.
-    expectedUiSpanNames: ['Application Render', 'Vue <Root>'],
+    expectedUiSpanNames: ['Application Render', 'Vue <Root>'].sort(),
   },
   {
     route: '/components',
     routeDescription: 'a route with an async component',
-    expectedUiSpanNames: ['Application Render', 'Vue <ComponentMainView>', 'Vue <ComponentOneView>', 'Vue <Root>'],
+    expectedUiSpanNames: OPTIONS_API_DISABLED
+      ? ['Application Render', 'Vue <Root>'].sort()
+      : ['Application Render', 'Vue <ComponentMainView>', 'Vue <ComponentOneView>', 'Vue <Root>'].sort(),
   },
 ].forEach(({ route, routeDescription, expectedUiSpanNames }) => {
   test(`sends an application render span and a root component span on ${routeDescription}`, async ({ page }) => {
-    // Vue compiles `app.mixin()` down to a no-op when the Options API is disabled, so the SDK creates no UI spans at all.
-    test.fail(OPTIONS_API_DISABLED, 'Vue tracing is registered through app.mixin(), which needs the Options API');
-
     const spansPromise = collectStreamedSpans('vue-3', spans => {
       return (
         spans.some(
@@ -163,9 +164,38 @@ test('sends a pageload span with a route name as span name if available', async
   });
 });
 
+// True on both variants: the mixin arms one debounce timer per component (`tracing.ts`), so a
+// late child never clears the root's earlier timer and the span ends at the root's mount. The
+// `app.mount()` wrap only observes the root, so it matches.
+test('ends the application render span before a delayed async component mounts', async ({ page }) => {
+  const spansPromise = collectStreamedSpans('vue-3', spans =>
+    spans.some(
+      span => span.is_segment && getSpanOp(span) === 'pageload' && span.attributes['url.path']?.value === '/delayed',
+    ),
+  );
+
+  await page.goto('/delayed');
+  // Proves the child really mounted after its delay; the duration assertion relies on it.
+  await expect(page.locator('#delayed-child')).toBeVisible();
+
+  const spans = await spansPromise;
+  const uiSpans = spans.filter(span => span.attributes['sentry.origin']?.value === 'auto.ui.vue');
+
+  // Neither `DelayedView` nor its child is in `trackComponents`, so both variants expect the same set.
+  expect(uiSpans.map(span => span.name).sort()).toEqual(['Application Render', 'Vue <Root>']);
+
+  const applicationRenderSpan = uiSpans.find(span => span.name === 'Application Render');
+  expect(applicationRenderSpan?.start_timestamp).toEqual(expect.any(Number));
+  expect(applicationRenderSpan?.end_timestamp).toEqual(expect.any(Number));
+
+  const duration = (applicationRenderSpan?.end_timestamp ?? 0) - (applicationRenderSpan?.start_timestamp ?? 0);
+  expect(duration).toBeLessThan(ASYNC_CHILD_DELAY_S);
+});
+
 test('sends a lifecycle span for the root and for each tracked component only', async ({ page }) => {
-  // Vue compiles `app.mixin()` down to a no-op when the Options API is disabled, so the SDK creates no UI spans at all.
-  test.fail(OPTIONS_API_DISABLED, 'Vue tracing is registered through app.mixin(), which needs the Options API');
+  // The root spans survive through the `app.mount()` wrap, but the tracked component spans asserted
+  // below still come from `app.mixin()`, which is a no-op when the Options API is disabled.
+  test.fail(OPTIONS_API_DISABLED, 'Component tracking (`trackComponents`) needs the Options API');
 
   const expectedUiSpanNames = ['Application Render', 'Vue <ComponentMainView>', 'Vue <ComponentOneView>', 'Vue <Root>'];
 

packages/vue/src/constants.ts

@@ -1,3 +1,6 @@
 import type { Operation } from './types';
 
 export const DEFAULT_HOOKS: Operation[] = ['activate', 'mount'];
+
+/** How long the root render span waits for further render activity before it ends. */
+export const DEFAULT_ROOT_SPAN_TIMEOUT = 2000;

packages/vue/src/integration.ts

@@ -1,9 +1,10 @@
 import { consoleSandbox, defineIntegration, GLOBAL_OBJ, hasSpansEnabled } from '@sentry/core';
-import { DEFAULT_HOOKS } from './constants';
+import { DEFAULT_HOOKS, DEFAULT_ROOT_SPAN_TIMEOUT } from './constants';
 import { DEBUG_BUILD } from './debug-build';
 import { attachErrorHandler } from './errorhandler';
+import { instrumentAppMountWithoutMixin } from './rootInstrumentation';
 import { createTracingMixins } from './tracing';
-import type { Options, Vue, VueOptions } from './types';
+import type { Options, TracingOptions, Vue, VueOptions } from './types';
 
 const globalWithVue = GLOBAL_OBJ as typeof GLOBAL_OBJ & { Vue: Vue };
 
@@ -13,7 +14,7 @@ const DEFAULT_CONFIG: VueOptions = {
   attachErrorHandler: true,
   tracingOptions: {
     hooks: DEFAULT_HOOKS,
-    timeout: 2000,
+    timeout: DEFAULT_ROOT_SPAN_TIMEOUT,
     trackComponents: false,
   },
 };
@@ -76,21 +77,35 @@ const vueInit = (app: Vue, options: Options): void => {
   if (hasSpansEnabled(options)) {
     const mixins = createTracingMixins(options.tracingOptions);
     app.mixin(mixins);
-    warnIfMixinWasDropped(app, mixins);
+    if (!mixinWasApplied(app, mixins)) {
+      instrumentAppMountWithoutMixin(app, mixins);
+      warnAboutLostComponentTracking(app, options.tracingOptions);
+    }
   }
 };
 
 /**
- * `app.mixin()` is a no-op when Options API is disabled (default in Nuxt 5).
- * Without mixins (Options API) users lose every UI span (render, mount, etc.)
-
+ * Reads back whether Vue accepted the mixin, because `app.mixin()` fails silently when the Options
+ * API is disabled (the Nuxt 5 default). A Vue 2 constructor has no `_context` and no Options API
+ * flag, so the mixin always applies there.
+ *
  * See: https://github.com/vuejs/core/blob/v3.5.41/packages/runtime-core/src/apiCreateApp.ts
  */
-function warnIfMixinWasDropped(app: Vue, mixin: unknown): void {
-  // Vue 2 has no `_context` and no Options API flag, so there is nothing to check.
+function mixinWasApplied(app: Vue, mixin: unknown): boolean {
   const mixins = (app as Vue & { _context?: { mixins?: unknown[] } })._context?.mixins;
+  return !mixins || mixins.includes(mixin);
+}
+
+/**
+ * Warns only when the dropped mixin loses component tracking the user opted into. The default
+ * spans still work through the `app.mount()` wrap, so a default config stays silent.
+ */
+function warnAboutLostComponentTracking(app: Vue, tracingOptions: Partial<TracingOptions> | undefined): void {
+  const trackComponents = tracingOptions?.trackComponents;
+  const losesComponentSpans =
+    trackComponents === true || (Array.isArray(trackComponents) && trackComponents.length > 0);
 
-  if (!mixins || mixins.includes(mixin)) {
+  if (!losesComponentSpans) {
     return;
   }
 
@@ -103,7 +118,7 @@ function warnIfMixinWasDropped(app: Vue, mixin: unknown): void {
   consoleSandbox(() => {
     // eslint-disable-next-line no-console
     console.warn(
-      `[@sentry/vue]: The Vue Options API is disabled (\`__VUE_OPTIONS_API__: false\`), so Sentry cannot record UI spans. You lose \`Application Render\` and the component mount, update and unmount spans. Errors, pageload spans and navigation spans still work. ${fix}`,
+      `[@sentry/vue]: The Vue Options API is disabled (\`__VUE_OPTIONS_API__: false\`). Sentry still records the \`Application Render\` and root component mount spans, but component tracking (\`trackComponents\`) needs the Options API. ${fix}`,
     );
   });
 }

packages/vue/src/rootInstrumentation.ts

@@ -0,0 +1,51 @@
+import type { Mixins, VueSentry } from './tracing';
+import type { Vue } from './types';
+
+const instrumentedApps = new WeakSet<Vue>();
+
+/**
+ * The mixin hooks only check `$root === this` to detect the root component, so a self-referential
+ * stand-in works in place of the real instance, which does not exist yet at wrap time.
+ */
+function createRootViewModel(): VueSentry {
+  const vm: { $root?: unknown; $props: Record<string, unknown> } = { $props: {} };
+  vm.$root = vm;
+  return vm as unknown as VueSentry;
+}
+
+/**
+ * Records the `Application Render` and root component mount spans by wrapping `app.mount()`, for
+ * builds where the Options API is compiled out and `app.mixin()` is a silent no-op (Nuxt 5 default).
+ *
+ * Vue runs all `mounted` hooks before `mount()` returns, so the wrap covers the same window as the
+ * mixin's root hooks. Late mounts extend neither path; the mixin's debounce timers are per component.
+ */
+export function instrumentAppMountWithoutMixin(app: Vue, mixins: Mixins): void {
+  // A second wrap would duplicate the root spans (e.g. user and Nuxt SDK both add the integration).
+  if (instrumentedApps.has(app)) {
+    return;
+  }
+
+  const appWithMount = app as Vue & { mount?: (...args: unknown[]) => unknown };
+  const originalMount = appWithMount.mount;
+  // Guards odd app-like objects; Vue 2 constructors lack `mount` but never get here (their `app.mixin()` works).
+  if (typeof originalMount !== 'function') {
+    return;
+  }
+
+  const vm = createRootViewModel();
+  instrumentedApps.add(app);
+
+  // `createTracingMixins` always merges `DEFAULT_HOOKS`, so the `mount` pair exists.
+  const mountHooks = mixins as Partial<Record<'beforeMount' | 'mounted', (this: VueSentry) => void>>;
+
+  appWithMount.mount = function (...args: unknown[]): unknown {
+    mountHooks.beforeMount?.call(vm);
+    try {
+      return originalMount.apply(this, args);
+    } finally {
+      // Also runs when mounting throws, so the started root component span always ends.
+      mountHooks.mounted?.call(vm);
+    }
+  };
+}

packages/vue/src/tracing.ts

@@ -3,7 +3,7 @@ import type { Span } from '@sentry/core';
 import { debug, timestampInSeconds, uniq } from '@sentry/core';
 import { SENTRY_OP } from '@sentry/conventions/attributes';
 import { UI_MOUNT, UI_RENDER, UI_UNMOUNT, UI_UPDATE } from '@sentry/conventions/op';
-import { DEFAULT_HOOKS } from './constants';
+import { DEFAULT_HOOKS, DEFAULT_ROOT_SPAN_TIMEOUT } from './constants';
 import { DEBUG_BUILD } from './debug-build';
 import type { Hook, Operation, TracingOptions, ViewModel, Vue } from './types';
 import { formatComponentName } from './vendor/components';
@@ -18,9 +18,9 @@ const VUE_OPERATION_TO_SPAN_OP: Record<Operation, string> = {
   destroy: UI_UNMOUNT,
 };
 
-type Mixins = Parameters<Vue['mixin']>[0];
+export type Mixins = Parameters<Vue['mixin']>[0];
 
-interface VueSentry extends ViewModel {
+export interface VueSentry extends ViewModel {
   readonly $root: VueSentry;
   $_sentryComponentSpans?: {
     [key: string]: Span | undefined;
@@ -73,7 +73,7 @@ export const createTracingMixins = (options: Partial<TracingOptions> = {}): Mixi
 
   const mixins: Mixins = {};
 
-  const rootComponentSpanFinalTimeout = options.timeout || 2000;
+  const rootComponentSpanFinalTimeout = options.timeout || DEFAULT_ROOT_SPAN_TIMEOUT;
 
   for (const operation of hooks) {
     // Retrieve corresponding hooks from Vue lifecycle.