Improve typing coverage (4/n)

🚀 Typing coverage

Let’s improve typing coverage of PyTorch Lightning together!

I’m creating a new issue in order to increase visibility. There are three older issues (#7037, #5023, #4698) which became stale over time.

Plan

Currently, there are 55 files which are excluded from mypy checks so that our CI does not fail. These files vastly differ in difficulty in order to make the typing complete. For this reason, we are introducing difficulty estimate for each file so that community members can choose to work on the files appropriate to their skill level.

Please, comment on this issue in order to reserve a particular file to work on. Once you do so, I will edit this top comment to avoid collisions. Once you think your work is finished, please open a PR referencing this issue which:

removes the corresponding line from pyproject.toml
and passes mypy checks with the corresponding line removed. You can test it locally by running mypy from root directory

If you are struggling with pushing it over the finish line, open the PR anyway and someone from our team will help you to get it there. 🚀

Please note, that it can happen that you may need to edit more than just one file. This is fine, but please keep in mind, that the goal of your PR will be to make the check passing for the chosen file. Also, please note that the difficulty is just an educated guess.

For those of you who are not familiar with the process of contributing a PR, we have prepared a simple guide that will walk you through the necessary steps. You can do it! 🚀 💪

List of files and guesstimated difficulty

Completed

Difficulty 1 of 3

pytorch_lightning/core/decorators.py #14044
pytorch_lightning/profilers/advanced.py @nninept #13792 ~- [ ] pytorch_lightning/profilers/base.py @LeeChanHyuk #13879~
pytorch_lightning/loggers/base.py @JustinGoheen #13494
pytorch_lightning/__setup__.py @CyprienRicque #13472 ~- [ ] pytorch_lightning/distributed/dist.py @puhuk #13492~
pytorch_lightning/strategies/single_device.py @CyprienRicque #13532
pytorch_lightning/trainer/optimizers.py @gautierdag #13470
pytorch_lightning/utilities/distributed.py @krishnakalyan3 #13678
pytorch_lightning/callbacks/finetuning.py @ar90n #13516
pytorch_lightning/loggers/mlflow.py @JustinGoheen ~~#13690~~ #13691
pytorch_lightning/tuner/tuning.py @donlapark ~~#13616~~ #13631
pytorch_lightning/strategies/single_tpu.py @CyprienRicque #13534
pytorch_lightning/strategies/ddp2.py @CyprienRicque #13535
pytorch_lightning/strategies/parallel.py @CyprienRicque #13556
pytorch_lightning/loggers/csv_logs.py @JustinGoheen #13538
pytorch_lightning/tuner/lr_finder.py @donlapark #13513 #13652
pytorch_lightning/strategies/dp.py @CyprienRicque #13564
pytorch_lightning/profilers/simple.py @krishnakalyan3 #14103
pytorch_lightning/strategies/sharded_spawn.py @krishnakalyan3 #14102
pytorch_lightning/demos/mnist_datamodule.py @alro923 #13929
pytorch_lightning/demos/boring_classes.py @krishnakalyan3 #14201
pytorch_lightning/tuner/batch_size_scaling.py @ar90n #13518

Difficulty 2 of 3

pytorch_lightning/loops/epoch/training_epoch_loop.py @himkt #13555
pytorch_lightning/core/mixins/device_dtype_mixin.py @krishnakalyan3 #13704
pytorch_lightning/loggers/comet.py @JustinGoheen #13689
pytorch_lightning/loggers/tensorboard.py @JustinGoheen #13688
pytorch_lightning/strategies/horovod.py @CyprienRicque #13570
pytorch_lightning/callbacks/model_checkpoint.py @BongYang #13617
pytorch_lightning/strategies/fully_sharded.py @BongYang #13941
pytorch_lightning/loggers/neptune.py @JustinGoheen #13692
pytorch_lightning/utilities/meta.py @nninept #13763 #13868
pytorch_lightning/strategies/tpu_spawn.py @BongYang #13813
pytorch_lightning/loggers/logger.py @JustinGoheen #13541
pytorch_lightning/loggers/wandb.py @gautierdag #13483
pytorch_lightning/callbacks/stochastic_weight_avg.py @donlapark #13685 #13860
pytorch_lightning/strategies/strategy.py @CyprienRicque #13519
pytorch_lightning/strategies/deepspeed.py @donlapark #13832
pytorch_lightning/strategies/ddp_spawn.py @donlapark #13865
pytorch_lightning/strategies/ipu.py @HalestormAI #13786
pytorch_lightning/trainer/connectors/callback_connector.py @krishnakalyan3 #13750
pytorch_lightning/strategies/ddp.py @lijm1358 #13885
pytorch_lightning/core/saving.py @JustinGoheen #13932
pytorch_lightning/callbacks/quantization.py @krishnakalyan3 #13782
pytorch_lightning/strategies/sharded.py @lijm1358 #14184
pytorch_lightning/core/datamodule.py @JustinGoheen #13693