Round 5 fixes: workerpool resize shrink, validator lazy session close, plugin config error handling, 422 message detail, tests

app/core/execution/worker_pool.py

@@ -84,19 +84,12 @@ class AsyncWorkerPool:
                     asyncio.create_task(self._worker_loop(i), name=f"{self.name}-worker-{i}")
                 )
         elif new_worker_count < self.worker_count:
-            for _ in range(self.worker_count - new_worker_count):
-                await self._queue.put(None)
-            await asyncio.sleep(0)
-            still_running = []
-            for w in self._workers:
-                if w.done():
-                    try:
-                        await w
-                    except asyncio.CancelledError:
-                        pass
-                else:
-                    still_running.append(w)
-            self._workers = still_running
+            excess_workers = self._workers[new_worker_count:]
+            self._workers = self._workers[:new_worker_count]
+            for w in excess_workers:
+                w.cancel()
+            if excess_workers:
+                await asyncio.gather(*excess_workers, return_exceptions=True)
         self.worker_count = new_worker_count
 
     async def _worker_loop(self, worker_id: int) -> None: