ref(core): Make event processing logs warnings (#5010)

It can be confusing to users why event processing errors log out as errors. Let's bump this down to warnings instead - which better represent how actionable most of these thrown errors are.

Author: AbhiPrasad

packages/core/src/baseclient.ts

@@ -545,7 +545,7 @@ export abstract class BaseClient<O extends ClientOptions> implements Client<O> {
         return finalEvent.event_id;
       },
       reason => {
-        IS_DEBUG_BUILD && logger.error(reason);
+        IS_DEBUG_BUILD && logger.warn(reason);
         return undefined;
       },
     );

packages/core/test/lib/base.test.ts

@@ -940,13 +940,13 @@ describe('BaseClient', () => {
       const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, beforeSend });
       const client = new TestClient(options);
       const captureExceptionSpy = jest.spyOn(client, 'captureException');
-      const loggerErrorSpy = jest.spyOn(logger, 'error');
+      const loggerWarnSpy = jest.spyOn(logger, 'warn');
 
       client.captureEvent({ message: 'hello' });
 
       expect(TestClient.instance!.event).toBeUndefined();
       expect(captureExceptionSpy).not.toBeCalled();
-      expect(loggerErrorSpy).toBeCalledWith(new SentryError('`beforeSend` returned `null`, will not send event.'));
+      expect(loggerWarnSpy).toBeCalledWith(new SentryError('`beforeSend` returned `null`, will not send event.'));
     });
 
     test('calls beforeSend and log info about invalid return value', () => {
@@ -958,12 +958,12 @@ describe('BaseClient', () => {
         // @ts-ignore we need to test regular-js behavior
         const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, beforeSend });
         const client = new TestClient(options);
-        const loggerErrorSpy = jest.spyOn(logger, 'error');
+        const loggerWarnSpy = jest.spyOn(logger, 'warn');
 
         client.captureEvent({ message: 'hello' });
 
         expect(TestClient.instance!.event).toBeUndefined();
-        expect(loggerErrorSpy).toBeCalledWith(
+        expect(loggerWarnSpy).toBeCalledWith(
           new SentryError('`beforeSend` method has to return `null` or a valid event.'),
         );
       }
@@ -1091,15 +1091,15 @@ describe('BaseClient', () => {
 
       const client = new TestClient(getDefaultTestClientOptions({ dsn: PUBLIC_DSN }));
       const captureExceptionSpy = jest.spyOn(client, 'captureException');
-      const loggerErrorSpy = jest.spyOn(logger, 'error');
+      const loggerWarnSpy = jest.spyOn(logger, 'warn');
       const scope = new Scope();
       scope.addEventProcessor(() => null);
 
       client.captureEvent({ message: 'hello' }, {}, scope);
 
       expect(TestClient.instance!.event).toBeUndefined();
       expect(captureExceptionSpy).not.toBeCalled();
-      expect(loggerErrorSpy).toBeCalledWith(new SentryError('An event processor returned null, will not send event.'));
+      expect(loggerWarnSpy).toBeCalledWith(new SentryError('An event processor returned null, will not send event.'));
     });
 
     // TODO(v7): Add back tests with client reports
@@ -1131,7 +1131,7 @@ describe('BaseClient', () => {
       const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN });
       const client = new TestClient(options);
       const captureExceptionSpy = jest.spyOn(client, 'captureException');
-      const loggerErrorSpy = jest.spyOn(logger, 'error');
+      const loggerWarnSpy = jest.spyOn(logger, 'warn');
       const scope = new Scope();
       const exception = new Error('sorry');
       scope.addEventProcessor(() => {
@@ -1147,7 +1147,7 @@ describe('BaseClient', () => {
         },
         originalException: exception,
       });
-      expect(loggerErrorSpy).toBeCalledWith(
+      expect(loggerWarnSpy).toBeCalledWith(
         new SentryError(
           `Event processing pipeline threw an error, original event will not be sent. Details have been sent as a new event.\nReason: ${exception}`,
         ),

packages/nextjs/test/index.client.test.ts

@@ -14,7 +14,7 @@ const global = getGlobalObject();
 
 const reactInit = jest.spyOn(SentryReact, 'init');
 const captureEvent = jest.spyOn(BaseClient.prototype, 'captureEvent');
-const logError = jest.spyOn(logger, 'error');
+const logWarn = jest.spyOn(logger, 'warn');
 
 describe('Client init()', () => {
   afterEach(() => {
@@ -75,7 +75,7 @@ describe('Client init()', () => {
 
     expect(transportSend).not.toHaveBeenCalled();
     expect(captureEvent.mock.results[0].value).toBeUndefined();
-    expect(logError).toHaveBeenCalledWith(new SentryError('An event processor returned null, will not send event.'));
+    expect(logWarn).toHaveBeenCalledWith(new SentryError('An event processor returned null, will not send event.'));
   });
 
   describe('integrations', () => {

packages/nextjs/test/index.server.test.ts

@@ -16,7 +16,7 @@ const global = getGlobalObject();
 (global as typeof global & { __rewriteFramesDistDir__: string }).__rewriteFramesDistDir__ = '.next';
 
 const nodeInit = jest.spyOn(SentryNode, 'init');
-const logError = jest.spyOn(logger, 'error');
+const logWarn = jest.spyOn(logger, 'warn');
 
 describe('Server init()', () => {
   afterEach(() => {
@@ -104,7 +104,7 @@ describe('Server init()', () => {
     await SentryNode.flush();
 
     expect(transportSend).not.toHaveBeenCalled();
-    expect(logError).toHaveBeenCalledWith(new SentryError('An event processor returned null, will not send event.'));
+    expect(logWarn).toHaveBeenCalledWith(new SentryError('An event processor returned null, will not send event.'));
   });
 
   it("initializes both global hub and domain hub when there's an active domain", () => {