fix: improve telemetry worker stderr cleanup (#3648)

* fix: improve telemetry worker stderr cleanup to prevent hanging

Replace setImmediate + destroy() with process.stderr.end() callback
to ensure all buffered writes are flushed before exiting. Add fallback
exit in finally block to prevent worker from hanging if end() fails.

This properly releases the inherited stderr file descriptor in debug
mode, preventing the parent process from being blocked.

* fix: only close stderr in telemetry worker when DEBUG is active

Only call process.stderr.end() when DEBUG env var is set, mirroring the
parent process logic where stderr is inherited only in DEBUG mode. When
stderr is ignored, closing it is unnecessary and could cause issues.

Author: eablack

src/lib/analytics-telemetry/telemetry-worker.ts

@@ -13,21 +13,27 @@ const MAX_WORKER_LIFETIME_MS = 10000
 
 /**
  * Close stderr before exiting to avoid keeping parent process alive
- * This is important when stderr is inherited in DEBUG mode
+ * This is only necessary when stderr is inherited in DEBUG mode
  */
 function exitWorker(code: number): void {
-  // Use setImmediate to allow any pending stderr writes to flush
-  // before destroying the stream
-  setImmediate(() => {
+  // Close stderr if it was inherited (DEBUG mode)
+  if (process.env.DEBUG) {
     try {
-      // Close stderr to release the file descriptor reference to parent
-      process.stderr.destroy()
-    } catch {
-      // Ignore errors during cleanup
+      // End stderr gracefully, flushing all pending writes
+      // This properly releases the file descriptor reference to parent
+      process.stderr.end(() => {
+        process.exit(code)
+      })
+    } finally {
+      // Fallback: ensure we exit even if end() fails or callback never fires
+      // Use setImmediate to give the end() callback a chance to run first
+      setImmediate(() => {
+        process.exit(code)
+      })
     }
-
+  } else {
     process.exit(code)
-  })
+  }
 }
 
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