Fix MusicGen SDPA (#31208)

* fix sdpa musicgen

* make style

* remove copied from statement from Musicgen SDPA

src/transformers/models/musicgen/modeling_musicgen.py

@@ -545,7 +545,6 @@ class MusicgenFlashAttention2(MusicgenAttention):
         )
 
 
-# Copied from transformers.models.bart.modeling_bart.BartSdpaAttention with Bart->Musicgen
 class MusicgenSdpaAttention(MusicgenAttention):
     def forward(
         self,
@@ -572,6 +571,23 @@ class MusicgenSdpaAttention(MusicgenAttention):
                 output_attentions=output_attentions,
             )
 
+        if (
+            attention_mask is not None
+            and (attention_mask.mean(dim=[1, 2, 3]) <= torch.finfo(attention_mask.dtype).min).any()
+        ):
+            logger.warning_once(
+                '`torch.nn.functional.scaled_dot_product_attention` does not support having an empty attention mask. Falling back to the manual attention implementation. This warning can be removed using the argument `attn_implementation="eager"` when loading the model.'
+                "Note that this probably happens because `guidance_scale>1` or because you used `get_unconditional_inputs`. See https://github.com/huggingface/transformers/issues/31189 for more information."
+            )
+            return super().forward(
+                hidden_states,
+                key_value_states=key_value_states,
+                past_key_value=past_key_value,
+                attention_mask=attention_mask,
+                layer_head_mask=layer_head_mask,
+                output_attentions=output_attentions,
+            )
+
         # if key_value_states are provided this layer is used as a cross-attention layer
         # for the decoder
         is_cross_attention = key_value_states is not None