Improved parameter validation for TorchForecastingModel

CHANGELOG.md

@@ -31,6 +31,8 @@ but cannot always guarantee backwards compatibility. Changes that may **break co
 
 ### For developers of the library:
 
+ - Reworked the `_validate_model_params` function of `TorchForecastingModel` to support more complicated cases of class inheritance. [#2908](https://github.com/unit8co/darts/pull/2908) by [Tim Rosenflanz](https://github.com/trosenflanz).
+
 ## [0.37.1](https://github.com/unit8co/darts/tree/0.37.1) (2025-08-18)
 
 ### For users of the library:

darts/models/forecasting/torch_forecasting_model.py

@@ -362,14 +362,24 @@ def encode_year(idx):
 
     @classmethod
     def _validate_model_params(cls, **kwargs):
-        """validate that parameters used at model creation are part of :class:`TorchForecastingModel`,
-        :class:`PLForecastingModule` or cls __init__ methods.
-        """
-        valid_kwargs = (
-            set(inspect.signature(TorchForecastingModel.__init__).parameters.keys())
-            | set(inspect.signature(PLForecastingModule.__init__).parameters.keys())
-            | set(inspect.signature(cls.__init__).parameters.keys())
+        # initiate with PLForecastingModule params that isn't part of the base class
+        valid_kwargs = set(
+            inspect.signature(PLForecastingModule.__init__).parameters.keys()
         )
+        # add params from the full list of base classes
+        for base in inspect.getmro(cls):
+            if base is object:
+                break
+            try:
+                sig = inspect.signature(base.__init__)
+                valid_kwargs.update(sig.parameters.keys())
+            except (ValueError, TypeError):
+                # In case a built-in class throws or __init__ is not introspectable
+                continue
+
+        # Remove 'self','args,'kwargs' from consideration
+        for generic_arg in ["self", "args", "kwargs"]:
+            valid_kwargs.discard(generic_arg)
 
         invalid_kwargs = [kwarg for kwarg in kwargs if kwarg not in valid_kwargs]