ref(replay): Log warning if sample rates are all undefined

packages/replay/src/integration.ts

@@ -192,6 +192,11 @@ Sentry.init({ replaysOnErrorSampleRate: ${errorSampleRate} })`,
     // Client is not available in constructor, so we need to wait until setupOnce
     this._loadReplayOptionsFromClient();
 
+    if (!this._options.sessionSampleRate && !this._options.errorSampleRate) {
+      // eslint-disable-next-line no-console
+      console.warn('Replay is disabled because both `replaysSessionSampleRate` and `replaysOnErrorSampleRate` are 0');
+    }
+
     this._replay = new ReplayContainer({
       options: this._options,
       recordingOptions: this._recordingOptions,

packages/replay/test/integration/integrationSettings.test.ts

@@ -53,14 +53,14 @@ describe('Integration | integrationSettings', () => {
       expect(mockConsole).toBeCalledTimes(1);
     });
 
-    it('works with defining 0 in integration', async () => {
+    it('works with defining 0 in integration but logs warnings', async () => {
       const { replay } = await mockSdk({
         replayOptions: { sessionSampleRate: 0 },
         sentryOptions: { replaysSessionSampleRate: undefined },
       });
 
       expect(replay.getOptions().sessionSampleRate).toBe(0);
-      expect(mockConsole).toBeCalledTimes(1);
+      expect(mockConsole).toBeCalledTimes(2);
     });
 
     it('works with defining settings in SDK', async () => {
@@ -70,11 +70,11 @@ describe('Integration | integrationSettings', () => {
       expect(mockConsole).toBeCalledTimes(0);
     });
 
-    it('works with defining 0 in SDK', async () => {
+    it('works with defining 0 in SDK but a warning is logged', async () => {
       const { replay } = await mockSdk({ sentryOptions: { replaysSessionSampleRate: 0 }, replayOptions: {} });
 
       expect(replay.getOptions().sessionSampleRate).toBe(0);
-      expect(mockConsole).toBeCalledTimes(0);
+      expect(mockConsole).toBeCalledTimes(1);
     });
 
     it('SDK option takes precedence', async () => {
@@ -87,14 +87,14 @@ describe('Integration | integrationSettings', () => {
       expect(mockConsole).toBeCalledTimes(1);
     });
 
-    it('SDK option takes precedence even when 0', async () => {
+    it('SDK option takes precedence even when 0 but warnings are logged', async () => {
       const { replay } = await mockSdk({
         sentryOptions: { replaysSessionSampleRate: 0 },
         replayOptions: { sessionSampleRate: 0.1 },
       });
 
       expect(replay.getOptions().sessionSampleRate).toBe(0);
-      expect(mockConsole).toBeCalledTimes(1);
+      expect(mockConsole).toBeCalledTimes(2);
     });
   });
 

packages/replay/test/integration/sampling.test.ts

@@ -5,6 +5,7 @@ useFakeTimers();
 
 describe('Integration | sampling', () => {
   it('does nothing if not sampled', async () => {
+    const mockConsole = jest.spyOn(console, 'warn').mockImplementation(jest.fn());
     const { record: mockRecord } = mockRrweb();
     const { replay } = await mockSdk({
       replayOptions: {
@@ -29,5 +30,6 @@ describe('Integration | sampling', () => {
     );
     expect(mockRecord).not.toHaveBeenCalled();
     expect(spyAddListeners).not.toHaveBeenCalled();
+    expect(mockConsole).toBeCalledTimes(1);
   });
 });

packages/replay/test/mocks/mockSdk.ts

@@ -75,7 +75,7 @@ export async function mockSdk({ replayOptions, sentryOptions, autoStart = true }
     integrations: [replayIntegration],
   });
 
-  // Instead of `setupOnce`, which is tricky to test, we call this manually here
+  // Instead of `setupOnce`, which is tricky to test, we call this manually here)
   replayIntegration['_setup']();
 
   if (autoStart) {