Error messages for removed Trainer mixin methods (#15065)

Co-authored-by: Carlos Mocholí <carlossmocholi@gmail.com>
Co-authored-by: Jirka Borovec <Borda@users.noreply.github.com>

src/pytorch_lightning/_graveyard/trainer.py

@@ -11,12 +11,34 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+import sys
 from typing import Any, Optional
 
 from pytorch_lightning import Trainer
 
 
+def _patch_sys_modules() -> None:
+    self = sys.modules[__name__]
+    sys.modules["pytorch_lightning.trainer.data_loading"] = self
+    sys.modules["pytorch_lightning.trainer.optimizers"] = self
+
+
+class TrainerDataLoadingMixin:
+    # TODO: Remove in v2.0.0
+    def __init__(self) -> None:
+        raise NotImplementedError(
+            "The `TrainerDataLoadingMixin` class was deprecated in v1.6 and is no longer supported as of v1.8."
+        )
+
+
+class TrainerOptimizersMixin:
+    # TODO: Remove in v2.0.0
+    def __init__(self) -> None:
+        raise NotImplementedError(
+            "The `TrainerOptimizersMixin` class was deprecated in v1.6 and is no longer supported as of v1.8."
+        )
+
+
 def _gpus(_: Trainer) -> None:
     # Remove in v2.0.0
     raise AttributeError(
@@ -169,6 +191,30 @@ def _call_hook(_: Trainer, *__: Any, **___: Any) -> Any:
     raise NotImplementedError("`Trainer.call_hook` was deprecated in v1.6 and is no longer supported as of v1.8.")
 
 
+def _prepare_dataloader(_: Trainer, *__: Any, **___: Any) -> None:
+    raise NotImplementedError(
+        "`Trainer.prepare_dataloader` was deprecated in v1.6 and is no longer supported as of v1.8."
+    )
+
+
+def _request_dataloader(_: Trainer, *__: Any, **___: Any) -> None:
+    raise NotImplementedError(
+        "`Trainer.request_dataloader` was deprecated in v1.6 and is no longer supported as of v1.8."
+    )
+
+
+def _init_optimizers(_: Trainer, *__: Any, **___: Any) -> None:
+    raise NotImplementedError("`Trainer.init_optimizers` was deprecated in v1.6 and is no longer supported as of v1.8.")
+
+
+def _convert_to_lightning_optimizers(_: Trainer) -> None:
+    raise NotImplementedError(
+        "`Trainer.convert_to_lightning_optimizers` was deprecated in v1.6 and is no longer supported as of v1.8."
+    )
+
+
+_patch_sys_modules()
+
 # Properties/Attributes
 Trainer.gpus = property(_gpus)
 Trainer.root_gpu = property(_root_gpu)
@@ -189,3 +235,7 @@ Trainer.verbose_evaluate = property(fget=_verbose_evaluate, fset=_verbose_evalua
 # Methods
 Trainer.run_stage = _run_stage
 Trainer.call_hook = _call_hook
+Trainer.prepare_dataloader = _prepare_dataloader
+Trainer.request_dataloader = _request_dataloader
+Trainer.init_optimizers = _init_optimizers
+Trainer.convert_to_lightning_optimizers = _convert_to_lightning_optimizers

tests/tests_pytorch/graveyard/test_trainer.py

@@ -75,3 +75,54 @@ def test_v2_0_0_unsupported_call_hook():
         NotImplementedError, match="`Trainer.call_hook` was deprecated in v1.6 and is no longer supported as of v1.8."
     ):
         trainer.call_hook("test_hook")
+
+
+def test_v2_0_0_unsupported_data_loading_mixin():
+    from pytorch_lightning.trainer.data_loading import TrainerDataLoadingMixin
+
+    class CustomTrainerDataLoadingMixin(TrainerDataLoadingMixin):
+        pass
+
+    with pytest.raises(
+        NotImplementedError,
+        match="`TrainerDataLoadingMixin` class was deprecated in v1.6 and is no longer supported as of v1.8",
+    ):
+        CustomTrainerDataLoadingMixin()
+
+    trainer = Trainer()
+    with pytest.raises(
+        NotImplementedError,
+        match="`Trainer.prepare_dataloader` was deprecated in v1.6 and is no longer supported as of v1.8.",
+    ):
+        trainer.prepare_dataloader(None)
+    with pytest.raises(
+        NotImplementedError,
+        match="`Trainer.request_dataloader` was deprecated in v1.6 and is no longer supported as of v1.8.",
+    ):
+        trainer.request_dataloader(None)
+
+
+def test_v2_0_0_trainer_optimizers_mixin():
+    from pytorch_lightning.trainer.optimizers import TrainerOptimizersMixin
+
+    class CustomTrainerOptimizersMixin(TrainerOptimizersMixin):
+        pass
+
+    with pytest.raises(
+        NotImplementedError,
+        match="`TrainerOptimizersMixin` class was deprecated in v1.6 and is no longer supported as of v1.8",
+    ):
+        CustomTrainerOptimizersMixin()
+
+    trainer = Trainer()
+    with pytest.raises(
+        NotImplementedError,
+        match="`Trainer.init_optimizers` was deprecated in v1.6 and is no longer supported as of v1.8.",
+    ):
+        trainer.init_optimizers(None)
+
+    with pytest.raises(
+        NotImplementedError,
+        match="`Trainer.convert_to_lightning_optimizers` was deprecated in v1.6 and is no longer supported as of v1.8.",
+    ):
+        trainer.convert_to_lightning_optimizers()