Use typing forward references (#7770)

* Use typing forward references

* Update pytorch_lightning/core/lightning.py

pytorch_lightning/core/lightning.py

@@ -324,9 +324,6 @@ class LightningModule(
                 ' `https://github.com/PyTorchLightning/pytorch-lightning/discussions`'
             )
 
-        if self._results is not None:
-            # TODO: if logged twice fail with crash
-
         # set the default depending on the fx_name
         on_step = self.__auto_choose_log_on_step(on_step)
         on_epoch = self.__auto_choose_log_on_epoch(on_epoch)
@@ -336,9 +333,7 @@ class LightningModule(
 
         # make sure user doesn't introduce logic for multi-dataloaders
         if "/dataloader_idx_" in name:
-                raise MisconfigurationException(
-                    f"Logged key: {name} should not contain information about dataloader_idx."
-                )
+            raise MisconfigurationException(f"Logged key: {name} should not contain information about dataloader_idx.")
 
         value = self.__sync(
             value,
@@ -349,6 +344,7 @@ class LightningModule(
             device=self.device,
         )
 
+        assert self._results is not None
         self._results.log(
             name,
             value,
@@ -378,7 +374,7 @@ class LightningModule(
         add_dataloader_idx: bool = True,
     ) -> None:
         """
-        Log a dictonary of values at once
+        Log a dictionary of values at once
 
         Example::
 

pytorch_lightning/overrides/base.py

@@ -15,13 +15,13 @@ import torch
 from torch.nn import DataParallel
 from torch.nn.parallel import DistributedDataParallel
 
-from pytorch_lightning.core.lightning import LightningModule
+import pytorch_lightning as pl
 from pytorch_lightning.utilities.device_dtype_mixin import DeviceDtypeModuleMixin
 
 
 class _LightningModuleWrapperBase(DeviceDtypeModuleMixin, torch.nn.Module):
 
-    def __init__(self, pl_module: LightningModule):
+    def __init__(self, pl_module: 'pl.LightningModule') -> None:
         """
         Wraps the user's LightningModule and redirects the forward call to the appropriate
         method, either ``training_step``, ``validation_step`` or ``test_step``.
@@ -66,7 +66,7 @@ class _LightningModuleWrapperBase(DeviceDtypeModuleMixin, torch.nn.Module):
         pass
 
 
-def unwrap_lightning_module(wrapped_model) -> LightningModule:
+def unwrap_lightning_module(wrapped_model) -> 'pl.LightningModule':
     model = wrapped_model
     if isinstance(model, (DistributedDataParallel, DataParallel)):
         model = model.module

pytorch_lightning/overrides/data_parallel.py

@@ -17,7 +17,7 @@ from typing import Any
 
 import torch
 
-from pytorch_lightning.core.lightning import LightningModule
+import pytorch_lightning as pl
 from pytorch_lightning.overrides.base import _LightningModuleWrapperBase
 from pytorch_lightning.utilities import rank_zero_warn
 from pytorch_lightning.utilities.apply_func import apply_to_collection
@@ -53,7 +53,7 @@ class LightningParallelModule(_LightningModuleWrapperBase):
 
     """
 
-    def __init__(self, pl_module: LightningModule):
+    def __init__(self, pl_module: 'pl.LightningModule') -> None:
         super().__init__(pl_module)
         _ignore_scalar_return_in_dp()
 

pytorch_lightning/overrides/distributed.py

@@ -18,13 +18,13 @@ import torch
 from torch.nn.parallel import DistributedDataParallel
 from torch.utils.data import BatchSampler, DistributedSampler, Sampler
 
-from pytorch_lightning.core.lightning import LightningModule
+import pytorch_lightning as pl
 from pytorch_lightning.overrides.base import _LightningModuleWrapperBase
 
 
 class LightningDistributedModule(_LightningModuleWrapperBase):
 
-    def __init__(self, pl_module: LightningModule):
+    def __init__(self, pl_module: 'pl.LightningModule') -> None:
         """
         Wraps the user's LightningModule and redirects the forward call to the appropriate
         method, either ``training_step``, ``validation_step``, ``test_step`` or ``predict``.

pytorch_lightning/plugins/precision/apex_amp.py

@@ -39,7 +39,7 @@ class ApexMixedPrecisionPlugin(MixedPrecisionPlugin):
     def master_params(self, optimizer: Optimizer) -> _PARAMETERS:
         return amp.master_params(optimizer)
 
-    def dispatch(self, trainer: "pl.Trainer") -> None:
+    def dispatch(self, trainer: 'pl.Trainer') -> None:
         if not self._connected:
             accelerator = trainer.accelerator
             _, accelerator.optimizers = amp.initialize(

pytorch_lightning/plugins/training_type/deepspeed.py

@@ -22,8 +22,8 @@ from typing import Any, Callable, Dict, Generator, List, Optional, Tuple, Union
 
 import torch
 
+import pytorch_lightning as pl
 from pytorch_lightning.callbacks import GradientAccumulationScheduler
-from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.overrides.base import _LightningModuleWrapperBase
 from pytorch_lightning.plugins.environments.cluster_environment import ClusterEnvironment
 from pytorch_lightning.plugins.training_type.ddp import DDPPlugin
@@ -51,7 +51,7 @@ def remove_module_hooks(model: torch.nn.Module) -> None:
 
 class LightningDeepSpeedModule(_LightningModuleWrapperBase):
 
-    def __init__(self, pl_module: LightningModule, precision: int):
+    def __init__(self, pl_module: 'pl.LightningModule', precision: int) -> None:
         super().__init__(pl_module)
         self.precision = precision
 
@@ -378,7 +378,7 @@ class DeepSpeedPlugin(DDPPlugin):
         distributed_sampler_kwargs = dict(num_replicas=self.world_size, rank=self.global_rank)
         return distributed_sampler_kwargs
 
-    def init_optimizers(self, trainer, model: LightningModule) -> Tuple[List, List, List]:
+    def init_optimizers(self, trainer: 'pl.Trainer', model: 'pl.LightningModule') -> Tuple[List, List, List]:
         # Skip initializing optimizers here as DeepSpeed handles optimizers via config.
         # User may have specified config options instead in configure_optimizers, but this is handled
         # via `_initialize_deepspeed_train`

pytorch_lightning/plugins/training_type/parallel.py

@@ -19,7 +19,7 @@ from typing import Any, List, Optional
 import torch
 from torch.nn.parallel import DistributedDataParallel
 
-from pytorch_lightning.core.lightning import LightningModule
+import pytorch_lightning as pl
 from pytorch_lightning.overrides.base import unwrap_lightning_module
 from pytorch_lightning.plugins.environments.cluster_environment import ClusterEnvironment
 from pytorch_lightning.plugins.training_type.training_type_plugin import TrainingTypePlugin
@@ -99,7 +99,7 @@ class ParallelPlugin(TrainingTypePlugin, ABC):
         return torch_backend
 
     @staticmethod
-    def configure_sync_batchnorm(model: LightningModule) -> LightningModule:
+    def configure_sync_batchnorm(model: 'pl.LightningModule') -> 'pl.LightningModule':
         """
         Add global batchnorm for a model spread across multiple GPUs and nodes.
 
@@ -112,8 +112,7 @@ class ParallelPlugin(TrainingTypePlugin, ABC):
         Return:
             LightningModule with batchnorm layers synchronized between process groups
         """
-        model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model)
-        return model
+        return torch.nn.SyncBatchNorm.convert_sync_batchnorm(model)
 
     @contextmanager
     def block_backward_sync(self):

tests/accelerators/test_multi_nodes_gpu.py

@@ -125,5 +125,5 @@ def test__validation_step__log(tmpdir):
     }
 
     # we don't want to enable val metrics during steps because it is not something that users should do
-    # on purpose DO NOT allow step_b... it's silly to monitor val step metrics
+    # on purpose DO NOT allow b_step... it's silly to monitor val step metrics
     assert set(trainer.callback_metrics) == {'a', 'a2', 'b', 'a_epoch', 'b_epoch', 'a_step'}