fix(node): Handle inspector already open (#10025)

If the inspector is already running, then ANR should be able to (re)use
that, instead of opening it itself.

packages/node-integration-tests/suites/anr/test.ts

@@ -95,6 +95,26 @@ conditionalTest({ min: 16 })('should report ANR when event loop blocked', () =>
     });
   });
 
+  test('With --inspect', done => {
+    expect.assertions(7);
+
+    const testScriptPath = path.resolve(__dirname, 'basic.js');
+
+    childProcess.exec(`node --inspect ${testScriptPath}`, { encoding: 'utf8' }, (_, stdout) => {
+      const [event] = parseJsonLines<[Event]>(stdout, 1);
+
+      expect(event.exception?.values?.[0].mechanism).toEqual({ type: 'ANR' });
+      expect(event.exception?.values?.[0].type).toEqual('ApplicationNotResponding');
+      expect(event.exception?.values?.[0].value).toEqual('Application Not Responding for at least 200 ms');
+      expect(event.exception?.values?.[0].stacktrace?.frames?.length).toBeGreaterThan(4);
+
+      expect(event.exception?.values?.[0].stacktrace?.frames?.[2].function).toEqual('?');
+      expect(event.exception?.values?.[0].stacktrace?.frames?.[3].function).toEqual('longWork');
+
+      done();
+    });
+  });
+
   test('With session', done => {
     expect.assertions(9);
 

packages/node/src/integrations/anr/index.ts

@@ -111,7 +111,9 @@ export class Anr implements Integration {
     if (options.captureStackTrace) {
       // eslint-disable-next-line @typescript-eslint/no-var-requires
       const inspector: InspectorApi = require('inspector');
-      inspector.open(0);
+      if (!inspector.url()) {
+        inspector.open(0);
+      }
     }
 
     const { Worker } = getWorkerThreads();