[BugFix] Ensure appropriate guards in destructors (#25284)

Signed-off-by: Nick Hill <nhill@redhat.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

vllm/compilation/collective_fusion.py

@@ -1183,7 +1183,7 @@ class AllReduceFusionPass(VllmInductorPass):
         self.end_and_log()
 
     def __del__(self):
-        if self.disabled:
+        if getattr(self, "disabled", True):
             return
         if flashinfer_comm is not None:
             flashinfer_comm.trtllm_destroy_ipc_workspace_for_all_reduce(

vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py

@@ -569,9 +569,10 @@ class NixlConnectorWorker:
 
     def __del__(self):
         """Cleanup background threads on destruction."""
-        self._handshake_initiation_executor.shutdown(wait=False)
-        if self._nixl_handshake_listener_t:
-            self._nixl_handshake_listener_t.join(timeout=0)
+        if executor := getattr(self, "_handshake_initiation_executor", None):
+            executor.shutdown(wait=False)
+        if listener_t := getattr(self, "_nixl_handshake_listener_t", None):
+            listener_t.join(timeout=0)
 
     @staticmethod
     def _nixl_handshake_listener(metadata: NixlAgentMetadata,
@@ -1379,4 +1380,4 @@ class NixlKVConnectorStats(KVConnectorStats):
         # TODO: reduce stats to a single value, calculate latency/throughput
         return {
             "num_successful_transfers": self.data["num_successful_transfers"]
-        }
\ No newline at end of file
+        }

vllm/executor/executor_base.py

@@ -235,9 +235,6 @@ class ExecutorBase(ABC):
         """Shutdown the executor."""
         self.collective_rpc("shutdown")
 
-    def __del__(self):
-        self.shutdown()
-
     async def execute_model_async(
             self,
             execute_model_req: ExecuteModelRequest) -> List[SamplerOutput]:

vllm/v1/worker/gpu_worker.py

@@ -683,7 +683,8 @@ class Worker(WorkerBase):
             tensorizer_config=tensorizer_config, )
 
     def shutdown(self) -> None:
-        self.model_runner.ensure_kv_transfer_shutdown()
+        if runner := getattr(self, "model_runner", None):
+            runner.ensure_kv_transfer_shutdown()
 
 
 def init_worker_distributed_environment(