[Bugfix] Always set RAY_ADDRESS for Ray actor before spawn (#21540)

Signed-off-by: Rui Qiao <ruisearch42@gmail.com>

vllm/utils/__init__.py

@@ -2883,26 +2883,27 @@ def _maybe_force_spawn():
     if os.environ.get("VLLM_WORKER_MULTIPROC_METHOD") == "spawn":
         return
 
-    reason = None
-    if cuda_is_initialized():
-        reason = "CUDA is initialized"
-    elif xpu_is_initialized():
-        reason = "XPU is initialized"
-    elif is_in_ray_actor():
+    reasons = []
+    if is_in_ray_actor():
         # even if we choose to spawn, we need to pass the ray address
         # to the subprocess so that it knows how to connect to the ray cluster.
         # env vars are inherited by subprocesses, even if we use spawn.
         import ray
         os.environ["RAY_ADDRESS"] = ray.get_runtime_context().gcs_address
-        reason = "In a Ray actor and can only be spawned"
+        reasons.append("In a Ray actor and can only be spawned")
+
+    if cuda_is_initialized():
+        reasons.append("CUDA is initialized")
+    elif xpu_is_initialized():
+        reasons.append("XPU is initialized")
 
-    if reason is not None:
+    if reasons:
         logger.warning(
             "We must use the `spawn` multiprocessing start method. "
             "Overriding VLLM_WORKER_MULTIPROC_METHOD to 'spawn'. "
             "See https://docs.vllm.ai/en/latest/usage/"
             "troubleshooting.html#python-multiprocessing "
-            "for more information. Reason: %s", reason)
+            "for more information. Reasons: %s", "; ".join(reasons))
         os.environ["VLLM_WORKER_MULTIPROC_METHOD"] = "spawn"