Generate: validate model_kwargs (and catch typos in generate arguments) (#18261)

* validate generate model_kwargs

* generate tests -- not all models have an attn mask

Author: gante

src/transformers/generation_utils.py

@@ -841,6 +841,29 @@ def compute_transition_beam_scores(
 
         return transition_scores
 
+    def _validate_model_kwargs(self, model_kwargs: Dict[str, Any]):
+        """Validates model kwargs for generation. Generate argument typos will also be caught here."""
+        # Excludes arguments that are handled before calling any model function
+        if self.config.is_encoder_decoder:
+            for key in ["decoder_input_ids"]:
+                model_kwargs.pop(key, None)
+
+        unused_model_args = []
+        model_args = set(inspect.signature(self.prepare_inputs_for_generation).parameters)
+        # `kwargs` if often used to handle optional forward pass inputs like `attention_mask`. If
+        # `prepare_inputs_for_generation` doesn't accept `kwargs`, then a stricter check can be made ;)
+        if "kwargs" in model_args:
+            model_args |= set(inspect.signature(self.forward).parameters)
+        for key, value in model_kwargs.items():
+            if value is not None and key not in model_args:
+                unused_model_args.append(key)
+
+        if unused_model_args:
+            raise ValueError(
+                f"The following `model_kwargs` are not used by the model: {unused_model_args} (note: typos in the"
+                " generate arguments will also show up in this list)"
+            )
+
     @torch.no_grad()
     def generate(
         self,
@@ -1120,6 +1143,9 @@ def generate(
         >>> tokenizer.batch_decode(outputs, skip_special_tokens=True)
         ['Paris ist eines der dichtesten besiedelten Gebiete Europas.']
         ```"""
+        # 0. Validate model kwargs
+        self._validate_model_kwargs(model_kwargs.copy())
+
         # 1. Set generation parameters if not already defined
         bos_token_id = bos_token_id if bos_token_id is not None else self.config.bos_token_id
         num_beams = num_beams if num_beams is not None else self.config.num_beams