Remove .replace [rebase and fixup into #16361] (#16383)

Author: carmocca

src/pytorch_lightning/loops/fit_loop.py

@@ -72,7 +72,6 @@ def batch_idx(self) -> int:
 
     @property
     def min_steps(self) -> Optional[int]:
-        # TODO(@justusschock): Why aren't we using the attribute in this class?
         """Returns the minimum number of steps to run."""
         return self.epoch_loop.min_steps
 

src/pytorch_lightning/loops/loop.py

@@ -11,16 +11,14 @@
 # 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 inspect
 from abc import ABC, abstractmethod
-from typing import Any, Dict, Generic, Optional, Type, TypeVar, Union
+from typing import Any, Dict, Generic, Optional, TypeVar
 
 from torchmetrics import Metric
 
 import pytorch_lightning as pl
 from pytorch_lightning.trainer.connectors.logger_connector.result import _ResultCollection
 from pytorch_lightning.trainer.progress import BaseProgress
-from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from pytorch_lightning.utilities.imports import _fault_tolerant_training
 
 T = TypeVar("T")  # the output type of `run`
@@ -108,52 +106,6 @@ def connect(self, **kwargs: "Loop") -> None:
         Linked loops should form a tree.
         """
 
-    def replace(self, **loops: Union["Loop", Type["Loop"]]) -> None:
-        """Optionally replace one or multiple of this loop's sub-loops.
-
-        This method takes care of instantiating the class (if necessary) with all existing arguments, connecting all
-        sub-loops of the old loop to the new instance, setting the ``Trainer`` reference, and connecting the new loop to
-        the parent.
-
-        Args:
-            **loops: ``Loop`` subclasses or instances. The name used should match the loop attribute name you want to
-                replace.
-
-        Raises:
-            MisconfigurationException: When passing a ``Loop`` class, if the ``__init__`` arguments do not match those
-                of the Loop class it replaces.
-        """
-        new_loops = {}
-
-        for name, type_or_object in loops.items():
-            old_loop = getattr(self, name)
-
-            if isinstance(type_or_object, type):
-                # compare the signatures
-                old_parameters = inspect.signature(old_loop.__class__.__init__).parameters
-                current_parameters = inspect.signature(type_or_object.__init__).parameters
-                if old_parameters != current_parameters:
-                    raise MisconfigurationException(
-                        f"`{self.__class__.__name__}.replace({type_or_object.__name__})` can only be used if the"
-                        f" `__init__` signatures match but `{old_loop.__class__.__name__}` does not."
-                    )
-                # instantiate the loop
-                kwargs = {p: getattr(old_loop, p) for p in old_parameters if p != "self"}
-                loop = type_or_object(**kwargs)
-            else:
-                loop = type_or_object
-
-            # connect sub-loops
-            kwargs = {n: l for n, l in old_loop.__dict__.items() if isinstance(l, Loop)}
-            if kwargs:
-                loop.connect(**kwargs)
-            # set the trainer reference
-            loop.trainer = self.trainer
-
-            new_loops[name] = loop
-        # connect to self
-        self.connect(**new_loops)
-
     def on_skip(self) -> T:
         """The function to run when :meth:`run` should be skipped, determined by the condition in :attr:`skip`.