fix tests

pytorch_lightning/trainer/trainer.py

@@ -58,7 +58,7 @@
     SimpleProfiler,
     XLAProfiler,
 )
-from pytorch_lightning.strategies import ParallelStrategy, SingleDeviceStrategy, Strategy
+from pytorch_lightning.strategies import ParallelStrategy, Strategy
 from pytorch_lightning.strategies.ddp_spawn import DDPSpawnStrategy
 from pytorch_lightning.trainer.callback_hook import TrainerCallbackHookMixin
 from pytorch_lightning.trainer.configuration_validator import verify_loop_configurations
@@ -2028,11 +2028,14 @@ def num_nodes(self) -> int:
 
     @property
     def device_ids(self) -> List[int]:
-        if isinstance(self.strategy, ParallelStrategy):
-            return [torch._utils._get_device_index(device, allow_cpu=True) for device in self.strategy.parallel_devices]
-        elif isinstance(self.strategy, SingleDeviceStrategy):
-            return [torch._utils._get_device_index(self.strategy.root_device, allow_cpu=True)]
-        return []
+        devices = getattr(self.strategy, "parallel_devices", [self.strategy.root_device])
+        device_ids = []
+        for idx, device in enumerate(devices):
+            if isinstance(device, torch.device):
+                device_ids.append(device.index or idx)
+            elif isinstance(device, int):
+                device_ids.append(device)
+        return device_ids
 
     @property
     def num_devices(self) -> int:

tests/trainer/test_trainer.py

@@ -2151,7 +2151,7 @@ def test_dataloaders_are_not_loaded_if_disabled_through_limit_batches(running_st
 @pytest.mark.parametrize(
     ["trainer_kwargs", "expected_device_ids"],
     [
-        ({"strategy": None}, []),
+        ({"strategy": None}, [0]),
         ({"num_processes": 1}, [0]),
         ({"gpus": 1}, [0]),
         ({"devices": 1}, [0]),
@@ -2166,4 +2166,4 @@ def test_trainer_config_device_ids(monkeypatch, trainer_kwargs, expected_device_
         monkeypatch.setattr(torch.cuda, "is_available", lambda: True)
         monkeypatch.setattr(torch.cuda, "device_count", lambda: 4)
     trainer = Trainer(**trainer_kwargs)
-    trainer.num_devices = expected_device_ids
+    assert trainer.device_ids == expected_device_ids