fix(core): Avoid prolonging idle span when starting standalone span

packages/core/src/tracing/idleSpan.ts

@@ -17,6 +17,7 @@ import {
 import { timestampInSeconds } from '../utils/time';
 import { freezeDscOnSpan, getDynamicSamplingContextFromSpan } from './dynamicSamplingContext';
 import { SentryNonRecordingSpan } from './sentryNonRecordingSpan';
+import { SentrySpan } from './sentrySpan';
 import { SPAN_STATUS_ERROR } from './spanstatus';
 import { startInactiveSpan } from './trace';
 
@@ -326,7 +327,12 @@ export function startIdleSpan(startSpanOptions: StartSpanOptions, options: Parti
       // or if this is the idle span itself being started,
       // or if the started span has already been closed,
       // we don't care about it for activity
-      if (_finished || startedSpan === span || !!spanToJSON(startedSpan).timestamp) {
+      if (
+        _finished ||
+        startedSpan === span ||
+        !!spanToJSON(startedSpan).timestamp ||
+        (startedSpan instanceof SentrySpan && startedSpan.isStandaloneSpan())
+      ) {
         return;
       }
 

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

@@ -586,6 +586,28 @@ describe('startIdleSpan', () => {
       expect(spanToJSON(idleSpan).status).not.toEqual('deadline_exceeded');
       expect(spanToJSON(idleSpan).timestamp).toBeDefined();
     });
+
+    it("doesn't reset the timeout for standalone spans", () => {
+      const idleSpan = startIdleSpan({ name: 'idle span' }, { finalTimeout: 99_999 });
+      expect(idleSpan).toBeDefined();
+
+      // Start any span to cancel idle timeout
+      startInactiveSpan({ name: 'span' });
+
+      // Wait some time
+      vi.advanceTimersByTime(TRACING_DEFAULTS.childSpanTimeout - 1000);
+      expect(spanToJSON(idleSpan).status).not.toEqual('deadline_exceeded');
+      expect(spanToJSON(idleSpan).timestamp).toBeUndefined();
+
+      // new standalone span should not reset the timeout
+      const standaloneSpan = startInactiveSpan({ name: 'standalone span', experimental: { standalone: true } });
+      expect(standaloneSpan).toBeDefined();
+
+      // Wait for timeout to exceed
+      vi.advanceTimersByTime(1001);
+      expect(spanToJSON(idleSpan).status).not.toEqual('deadline_exceeded');
+      expect(spanToJSON(idleSpan).timestamp).toBeDefined();
+    });
   });
 
   describe('disableAutoFinish', () => {