fix(tracing): Account for case where startTransaction returns undefined (#7566)

Author: AbhiPrasad

packages/core/src/tracing/trace.ts

@@ -7,14 +7,17 @@ import type { Span } from './span';
 /**
  * Wraps a function with a transaction/span and finishes the span after the function is done.
  *
+ * Note that if you have not enabled tracing extensions via `addTracingExtensions`, this function
+ * will not generate spans, and the `span` returned from the callback may be undefined.
+ *
  * This function is meant to be used internally and may break at any time. Use at your own risk.
  *
  * @internal
  * @private
  */
 export function trace<T>(
   context: TransactionContext,
-  callback: (span: Span) => T,
+  callback: (span?: Span) => T,
   // eslint-disable-next-line @typescript-eslint/no-empty-function
   onError: (error: unknown) => void = () => {},
 ): T {
@@ -32,15 +35,15 @@ export function trace<T>(
   scope.setSpan(activeSpan);
 
   function finishAndSetSpan(): void {
-    activeSpan.finish();
+    activeSpan && activeSpan.finish();
     hub.getScope().setSpan(parentSpan);
   }
 
   let maybePromiseResult: T;
   try {
     maybePromiseResult = callback(activeSpan);
   } catch (e) {
-    activeSpan.setStatus('internal_error');
+    activeSpan && activeSpan.setStatus('internal_error');
     onError(e);
     finishAndSetSpan();
     throw e;
@@ -52,7 +55,7 @@ export function trace<T>(
         finishAndSetSpan();
       },
       e => {
-        activeSpan.setStatus('internal_error');
+        activeSpan && activeSpan.setStatus('internal_error');
         onError(e);
         finishAndSetSpan();
       },

packages/core/test/lib/tracing/trace.test.ts

@@ -47,6 +47,21 @@ describe('trace', () => {
       }
     });
 
+    it('should return the same value as the callback if transactions are undefined', async () => {
+      // @ts-ignore we are force overriding the transaction return to be undefined
+      // The `startTransaction` types are actually wrong - it can return undefined
+      // if tracingExtensions are not enabled
+      jest.spyOn(hub, 'startTransaction').mockReturnValue(undefined);
+      try {
+        const result = await trace({ name: 'GET users/[id]' }, () => {
+          return callback();
+        });
+        expect(result).toEqual(expected);
+      } catch (e) {
+        expect(e).toEqual(expected);
+      }
+    });
+
     it('creates a transaction', async () => {
       let ref: any = undefined;
       client.on('finishTransaction', transaction => {
@@ -99,7 +114,9 @@ describe('trace', () => {
       });
       try {
         await trace({ name: 'GET users/[id]' }, span => {
-          span.op = 'http.server';
+          if (span) {
+            span.op = 'http.server';
+          }
           return callback();
         });
       } catch (e) {
@@ -138,7 +155,9 @@ describe('trace', () => {
       try {
         await trace({ name: 'GET users/[id]', parentSampled: true }, () => {
           return trace({ name: 'SELECT * from users' }, childSpan => {
-            childSpan.op = 'db.query';
+            if (childSpan) {
+              childSpan.op = 'db.query';
+            }
             return callback();
           });
         });