fix(profiling): Fix app start transaction profile timestamp offset (#5962)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: antonis

CHANGELOG.md

@@ -10,7 +10,8 @@
 
 ### Fixes
 
-- Use React `componentStack` as fallback when error has no stack trace on Android ([#5965](https://github.com/getsentry/sentry-react-native/pull/5965)
+- Fix app start transaction profile offset by using the actual profiling start timestamp instead of the adjusted app start time ([#5962](https://github.com/getsentry/sentry-react-native/issues/5962))
+- Use React `componentStack` as fallback when error has no stack trace on Android ([#5965](https://github.com/getsentry/sentry-react-native/pull/5965))
 - Add `SENTRY_PROJECT_ROOT` env var to override project root in Xcode build phase scripts for monorepo setups ([#5961](https://github.com/getsentry/sentry-react-native/pull/5961))
 
 ### Features

packages/core/src/js/profiling/integration.ts

@@ -279,9 +279,17 @@ export function stopProfiling(
     return null;
   }
 
+  hermesProfileEvent.profilingStartTimestampNs = profileStartTimestampNs;
+
   if (collectedProfiles.androidProfile) {
     const durationNs = profileEndTimestampNs - profileStartTimestampNs;
-    return createAndroidWithHermesProfile(hermesProfileEvent, collectedProfiles.androidProfile, durationNs);
+    const androidProfile = createAndroidWithHermesProfile(
+      hermesProfileEvent,
+      collectedProfiles.androidProfile,
+      durationNs,
+    );
+    androidProfile.profilingStartTimestampNs = profileStartTimestampNs;
+    return androidProfile;
   } else if (collectedProfiles.nativeProfile) {
     return addNativeProfileToHermesProfile(hermesProfileEvent, collectedProfiles.nativeProfile);
   }

packages/core/src/js/profiling/types.ts

@@ -15,6 +15,7 @@ export type HermesProfileEvent = {
   transaction: {
     active_thread_id: string;
   };
+  profilingStartTimestampNs?: number;
 };
 
 /*
@@ -31,6 +32,7 @@ export type AndroidCombinedProfileEvent = {
   android_api_level: number;
   duration_ns: string;
   active_thread_id: string;
+  profilingStartTimestampNs?: number;
 };
 
 /*

packages/core/src/js/profiling/utils.ts

@@ -88,14 +88,20 @@ export function enrichCombinedProfileWithEventContext(
     }
   }
 
+  const { profilingStartTimestampNs, ...profileWithoutInternalFields } = profile;
+
   return {
-    ...profile,
+    ...profileWithoutInternalFields,
     event_id: profile_id,
     runtime: {
       name: 'hermes',
       version: '', // TODO: get hermes version
     },
-    timestamp: event.start_timestamp ? new Date(event.start_timestamp * 1000).toISOString() : new Date().toISOString(),
+    timestamp: profilingStartTimestampNs
+      ? new Date(profilingStartTimestampNs / 1e6).toISOString()
+      : event.start_timestamp
+        ? new Date(event.start_timestamp * 1000).toISOString()
+        : new Date().toISOString(),
     release: event.release || '',
     environment: event.environment || getDefaultEnvironment(),
     os: {
@@ -130,8 +136,10 @@ export function enrichAndroidProfileWithEventContext(
   profile: AndroidCombinedProfileEvent,
   event: Event,
 ): AndroidProfileEvent | null {
+  const { profilingStartTimestampNs, ...profileWithoutInternalFields } = profile;
+
   return {
-    ...profile,
+    ...profileWithoutInternalFields,
     debug_meta: {
       images: getDebugMetadata(),
     },
@@ -152,7 +160,11 @@ export function enrichAndroidProfileWithEventContext(
 
     profile_id,
 
-    timestamp: event.start_timestamp ? new Date(event.start_timestamp * 1000).toISOString() : new Date().toISOString(),
+    timestamp: profilingStartTimestampNs
+      ? new Date(profilingStartTimestampNs / 1e6).toISOString()
+      : event.start_timestamp
+        ? new Date(event.start_timestamp * 1000).toISOString()
+        : new Date().toISOString(),
 
     release: event.release || '',
     dist: event.dist || '',

packages/core/test/profiling/utils.test.ts

@@ -0,0 +1,150 @@
+jest.mock('../../src/js/utils/environment');
+jest.mock('../../src/js/profiling/debugid');
+
+import type { Event } from '@sentry/core';
+
+import type { AndroidCombinedProfileEvent, CombinedProfileEvent } from '../../src/js/profiling/types';
+
+import { getDebugMetadata } from '../../src/js/profiling/debugid';
+import {
+  enrichAndroidProfileWithEventContext,
+  enrichCombinedProfileWithEventContext,
+} from '../../src/js/profiling/utils';
+import { getDefaultEnvironment } from '../../src/js/utils/environment';
+import { createMockMinimalValidAndroidProfile, createMockMinimalValidHermesProfileEvent } from './fixtures';
+
+describe('enrichCombinedProfileWithEventContext', () => {
+  beforeEach(() => {
+    (getDefaultEnvironment as jest.Mock).mockReturnValue('production');
+    (getDebugMetadata as jest.Mock).mockReturnValue([]);
+  });
+
+  function createMockEvent(overrides?: Partial<Event>): Event {
+    return {
+      event_id: 'test-event-id',
+      transaction: 'test-transaction',
+      release: 'test-release',
+      environment: 'test-env',
+      start_timestamp: 1000,
+      contexts: {
+        trace: {
+          trace_id: '12345678901234567890123456789012',
+        },
+        os: { name: 'iOS', version: '17.0' },
+        device: {},
+      },
+      ...overrides,
+    };
+  }
+
+  test('should use profilingStartTimestampNs for timestamp when available', () => {
+    const profilingStartTimestampNs = 1500 * 1e9; // 1500 seconds in ns
+    const profile: CombinedProfileEvent = {
+      ...createMockMinimalValidHermesProfileEvent(),
+      profilingStartTimestampNs,
+    };
+    const event = createMockEvent({ start_timestamp: 1000 }); // earlier than profiling start
+
+    const result = enrichCombinedProfileWithEventContext('profile-id', profile, event);
+
+    expect(result).not.toBeNull();
+    expect(result!.timestamp).toBe(new Date(profilingStartTimestampNs / 1e6).toISOString());
+    // Should NOT use event.start_timestamp
+    expect(result!.timestamp).not.toBe(new Date(1000 * 1000).toISOString());
+  });
+
+  test('should fall back to event.start_timestamp when profilingStartTimestampNs is not set', () => {
+    const profile: CombinedProfileEvent = createMockMinimalValidHermesProfileEvent();
+    const event = createMockEvent({ start_timestamp: 1000 });
+
+    const result = enrichCombinedProfileWithEventContext('profile-id', profile, event);
+
+    expect(result).not.toBeNull();
+    expect(result!.timestamp).toBe(new Date(1000 * 1000).toISOString());
+  });
+
+  test('should not include profilingStartTimestampNs in the output', () => {
+    const profile: CombinedProfileEvent = {
+      ...createMockMinimalValidHermesProfileEvent(),
+      profilingStartTimestampNs: 1500 * 1e9,
+    };
+    const event = createMockEvent();
+
+    const result = enrichCombinedProfileWithEventContext('profile-id', profile, event);
+
+    expect(result).not.toBeNull();
+    expect(result).not.toHaveProperty('profilingStartTimestampNs');
+  });
+});
+
+describe('enrichAndroidProfileWithEventContext', () => {
+  beforeEach(() => {
+    (getDefaultEnvironment as jest.Mock).mockReturnValue('production');
+    (getDebugMetadata as jest.Mock).mockReturnValue([]);
+  });
+
+  function createMockEvent(overrides?: Partial<Event>): Event {
+    return {
+      event_id: 'test-event-id',
+      transaction: 'test-transaction',
+      release: 'test-release',
+      environment: 'test-env',
+      start_timestamp: 1000,
+      contexts: {
+        trace: {
+          trace_id: '12345678901234567890123456789012',
+        },
+        os: { name: 'Android', version: '14' },
+        device: {},
+      },
+      ...overrides,
+    };
+  }
+
+  function createMockAndroidCombinedProfile(
+    overrides?: Partial<AndroidCombinedProfileEvent>,
+  ): AndroidCombinedProfileEvent {
+    const hermesProfileEvent = createMockMinimalValidHermesProfileEvent();
+    return {
+      platform: 'android',
+      sampled_profile: createMockMinimalValidAndroidProfile().sampled_profile,
+      js_profile: hermesProfileEvent.profile,
+      android_api_level: 34,
+      duration_ns: '1000000',
+      active_thread_id: '123',
+      ...overrides,
+    };
+  }
+
+  test('should use profilingStartTimestampNs for timestamp when available', () => {
+    const profilingStartTimestampNs = 1500 * 1e9;
+    const profile = createMockAndroidCombinedProfile({ profilingStartTimestampNs });
+    const event = createMockEvent({ start_timestamp: 1000 });
+
+    const result = enrichAndroidProfileWithEventContext('profile-id', profile, event);
+
+    expect(result).not.toBeNull();
+    expect(result!.timestamp).toBe(new Date(profilingStartTimestampNs / 1e6).toISOString());
+    expect(result!.timestamp).not.toBe(new Date(1000 * 1000).toISOString());
+  });
+
+  test('should fall back to event.start_timestamp when profilingStartTimestampNs is not set', () => {
+    const profile = createMockAndroidCombinedProfile();
+    const event = createMockEvent({ start_timestamp: 1000 });
+
+    const result = enrichAndroidProfileWithEventContext('profile-id', profile, event);
+
+    expect(result).not.toBeNull();
+    expect(result!.timestamp).toBe(new Date(1000 * 1000).toISOString());
+  });
+
+  test('should not include profilingStartTimestampNs in the output', () => {
+    const profile = createMockAndroidCombinedProfile({ profilingStartTimestampNs: 1500 * 1e9 });
+    const event = createMockEvent();
+
+    const result = enrichAndroidProfileWithEventContext('profile-id', profile, event);
+
+    expect(result).not.toBeNull();
+    expect(result).not.toHaveProperty('profilingStartTimestampNs');
+  });
+});