[From ckpt] Fix from_ckpt (#3466)

* Correct from_ckpt

* make style

src/diffusers/loaders.py

@@ -1326,7 +1326,7 @@ def from_ckpt(cls, pretrained_model_link_or_path, **kwargs):
         file_extension = pretrained_model_link_or_path.rsplit(".", 1)[-1]
         from_safetensors = file_extension == "safetensors"
 
-        if from_safetensors and use_safetensors is True:
+        if from_safetensors and use_safetensors is False:
             raise ValueError("Make sure to install `safetensors` with `pip install safetensors`.")
 
         # TODO: For now we only support stable diffusion

src/diffusers/pipelines/stable_diffusion/convert_from_ckpt.py

@@ -140,17 +140,17 @@ def renew_vae_attention_paths(old_list, n_shave_prefix_segments=0):
         new_item = new_item.replace("norm.weight", "group_norm.weight")
         new_item = new_item.replace("norm.bias", "group_norm.bias")
 
-        new_item = new_item.replace("q.weight", "query.weight")
-        new_item = new_item.replace("q.bias", "query.bias")
+        new_item = new_item.replace("q.weight", "to_q.weight")
+        new_item = new_item.replace("q.bias", "to_q.bias")
 
-        new_item = new_item.replace("k.weight", "key.weight")
-        new_item = new_item.replace("k.bias", "key.bias")
+        new_item = new_item.replace("k.weight", "to_k.weight")
+        new_item = new_item.replace("k.bias", "to_k.bias")
 
-        new_item = new_item.replace("v.weight", "value.weight")
-        new_item = new_item.replace("v.bias", "value.bias")
+        new_item = new_item.replace("v.weight", "to_v.weight")
+        new_item = new_item.replace("v.bias", "to_v.bias")
 
-        new_item = new_item.replace("proj_out.weight", "proj_attn.weight")
-        new_item = new_item.replace("proj_out.bias", "proj_attn.bias")
+        new_item = new_item.replace("proj_out.weight", "to_out.0.weight")
+        new_item = new_item.replace("proj_out.bias", "to_out.0.bias")
 
         new_item = shave_segments(new_item, n_shave_prefix_segments=n_shave_prefix_segments)
 
@@ -204,8 +204,12 @@ def assign_to_checkpoint(
                 new_path = new_path.replace(replacement["old"], replacement["new"])
 
         # proj_attn.weight has to be converted from conv 1D to linear
-        if "proj_attn.weight" in new_path:
+        is_attn_weight = "proj_attn.weight" in new_path or ("attentions" in new_path and "to_" in new_path)
+        shape = old_checkpoint[path["old"]].shape
+        if is_attn_weight and len(shape) == 3:
             checkpoint[new_path] = old_checkpoint[path["old"]][:, :, 0]
+        elif is_attn_weight and len(shape) == 4:
+            checkpoint[new_path] = old_checkpoint[path["old"]][:, :, 0, 0]
         else:
             checkpoint[new_path] = old_checkpoint[path["old"]]