fix signature in callbacks to prevent deprecation warning

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 
+## [1.4.6] - unreleased
+
+- Fixed signature of `Timer.on_train_epoch_end` and `StochasticWeightAveraging.on_train_epoch_end` to prevent unwanted deprecation warnings ([#9347](https://github.com/PyTorchLightning/pytorch-lightning/pull/9347))
+
+
 ## [1.4.5] - 2021-08-31
 
 - Fixed reduction using `self.log(sync_dict=True, reduce_fx={mean,max})` ([#9142](https://github.com/PyTorchLightning/pytorch-lightning/pull/9142))

pytorch_lightning/callbacks/stochastic_weight_avg.py

@@ -216,7 +216,7 @@ def on_train_epoch_start(self, trainer: "pl.Trainer", pl_module: "pl.LightningMo
 
             trainer.accumulate_grad_batches = trainer.num_training_batches
 
-    def on_train_epoch_end(self, trainer: "pl.Trainer", *args):
+    def on_train_epoch_end(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule", unused: Optional = None):
         trainer.fit_loop._skip_backward = False
 
     def on_train_end(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule"):

pytorch_lightning/callbacks/timer.py

@@ -148,7 +148,9 @@ def on_train_batch_end(self, trainer: "pl.Trainer", *args, **kwargs) -> None:
             return
         self._check_time_remaining(trainer)
 
-    def on_train_epoch_end(self, trainer: "pl.Trainer", *args, **kwargs) -> None:
+    def on_train_epoch_end(
+        self, trainer: "pl.Trainer", pl_module: "pl.LightningModule", unused: Optional = None
+    ) -> None:
         if self._interval != Interval.epoch or self._duration is None:
             return
         self._check_time_remaining(trainer)

tests/callbacks/test_timer.py

@@ -24,6 +24,7 @@
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from tests.helpers import BoringModel
 from tests.helpers.runif import RunIf
+from tests.helpers.utils import no_warning_call
 
 
 def test_trainer_flag(caplog):
@@ -106,7 +107,9 @@ def test_timer_stops_training(tmpdir, caplog):
     timer = Timer(duration=duration)
 
     trainer = Trainer(default_root_dir=tmpdir, max_epochs=1000, callbacks=[timer])
-    with caplog.at_level(logging.INFO):
+    with caplog.at_level(logging.INFO), no_warning_call(
+        DeprecationWarning, match="The signature of `Callback.on_train_epoch_end` has changed in v1.3"
+    ):
         trainer.fit(model)
     assert trainer.global_step > 1
     assert trainer.current_epoch < 999