Fix AttributeError: 'NoneType' object has no attribute 'finalize' on …

…TPU (#6221)

* Fix bug

Fix AttributeError: 'NoneType' object has no attribute 'finalize'

* Update CHANGELOG.md

* deleted a period

* Update CHANGELOG.md

Co-authored-by: Akihiro Nitta <nitta@akihironitta.com>

* Update CHANGELOG.md

* Update pytorch_lightning/plugins/training_type/tpu_spawn.py

Co-authored-by: Rohit Gupta <rohitgr1998@gmail.com>

Co-authored-by: Akihiro Nitta <nitta@akihironitta.com>
Co-authored-by: Carlos Mocholí <carlossmocholi@gmail.com>
Co-authored-by: Rohit Gupta <rohitgr1998@gmail.com>

CHANGELOG.md

@@ -98,6 +98,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Expose DeepSpeed loss parameters to allow users to fix loss instability ([#6115](https://github.com/PyTorchLightning/pytorch-lightning/pull/6115))
 
 
+- Fixed `AttributeError` when `logger=None` on TPU ([#6221](https://github.com/PyTorchLightning/pytorch-lightning/pull/6221))
+
+
 - Fixed `ModelPruning(make_pruning_permanent=True)` pruning buffers getting removed when saved during training ([#6073](https://github.com/PyTorchLightning/pytorch-lightning/pull/6073))
 
 

pytorch_lightning/plugins/training_type/tpu_spawn.py

@@ -262,7 +262,7 @@ def __load_weights_on_main_process(self) -> None:
         self._model = model
 
     def _close_logger(self, trainer) -> None:
-        if hasattr(trainer, "logger"):
+        if trainer.logger is not None:
             trainer.logger.finalize("success")
 
     @property