fix llava (huggingface#27909)

* fix llava

* nits

* attention_mask was forgotten

* nice

* :)

* fixup

src/transformers/models/llava/modeling_llava.py

@@ -22,6 +22,7 @@
 
 from ... import PreTrainedModel
 from ...activations import ACT2FN
+from ...cache_utils import Cache
 from ...modeling_outputs import ModelOutput
 from ...utils import (
     add_start_docstrings,
@@ -472,14 +473,57 @@ def forward(
         )
 
     def prepare_inputs_for_generation(
-        self, input_ids, past_key_values=None, inputs_embeds=None, pixel_values=None, **kwargs
+        self, input_ids, past_key_values=None, inputs_embeds=None, pixel_values=None, attention_mask=None, **kwargs
     ):
-        # Call `prepare_inputs_for_generation` from the LM
-        model_input = self.language_model.prepare_inputs_for_generation(
-            input_ids, past_key_values, inputs_embeds=inputs_embeds, **kwargs
+        if past_key_values is not None:
+            if isinstance(past_key_values, Cache):
+                cache_length = past_key_values.get_seq_length()
+                past_length = past_key_values.seen_tokens
+            else:
+                cache_length = past_length = past_key_values[0][0].shape[2]
+
+            # Keep only the unprocessed tokens:
+            # 1 - If the length of the attention_mask exceeds the length of input_ids, then we are in a setting where
+            # some of the inputs are exclusivelly passed as part of the cache (e.g. when passing input_embeds as
+            # input)
+            if attention_mask is not None and attention_mask.shape[1] > input_ids.shape[1]:
+                input_ids = input_ids[:, -(attention_mask.shape[1] - past_length) :]
+            # 2 - If the past_length is smaller than input_ids', then input_ids holds all input tokens. We can discard
+            # input_ids based on the past_length.
+            elif past_length < input_ids.shape[1]:
+                input_ids = input_ids[:, past_length:]
+            # 3 - Otherwise (past_length >= input_ids.shape[1]), let's assume input_ids only has unprocessed tokens.
+            elif self.config.image_token_index in input_ids:
+                input_ids = input_ids[:, input_ids.shape[1] - 1 :]
+            # If the cache has seen more tokens than it can hold, then the cache has a size limit. Let's discard the
+            # older attention values, as their corresponding values are not part of the input.
+            if cache_length < past_length and attention_mask is not None:
+                attention_mask = attention_mask[:, -(cache_length + input_ids.shape[1]) :]
+
+        position_ids = kwargs.get("position_ids", None)
+        if attention_mask is not None and position_ids is None:
+            # create position_ids on the fly for batch generation
+            position_ids = attention_mask.long().cumsum(-1) - 1
+            position_ids.masked_fill_(attention_mask == 0, 1)
+            if past_key_values:
+                position_ids = position_ids[:, -input_ids.shape[1] :]
+
+        # if `inputs_embeds` are passed, we only want to use them in the 1st generation step
+        if inputs_embeds is not None and past_key_values is None:
+            model_inputs = {"inputs_embeds": inputs_embeds}
+        else:
+            model_inputs = {"input_ids": input_ids}
+
+        model_inputs.update(
+            {
+                "position_ids": position_ids,
+                "past_key_values": past_key_values,
+                "use_cache": kwargs.get("use_cache"),
+                "attention_mask": attention_mask,
+                "pixel_values": pixel_values,
+            }
         )
-        model_input.update({"pixel_values": pixel_values})
-        return model_input
+        return model_inputs
 
     def _reorder_cache(self, *args, **kwargs):
         return self.language_model._reorder_cache(*args, **kwargs)