[Single File] Add single file support for Wan T2V/I2V

docs/source/en/api/pipelines/wan.md

@@ -45,6 +45,22 @@ pipe = WanPipeline.from_pretrained("Wan-AI/Wan2.1-T2V-1.3B-Diffusers", scheduler
 pipe.scheduler = <CUSTOM_SCHEDULER_HERE>
 ```
 
+### Using single file loading with Wan
+
+The `WanTransformer3DModel` and `AutoencoderKLWan` models support loading checkpoints in their original format via the `from_single_file` loading 
+method. 
+
+
+```python
+import torch
+from diffusers import WanPipeline, WanTransformer3DModel
+
+ckpt_path = "https://huggingface.co/Comfy-Org/Wan_2.1_ComfyUI_repackaged/blob/main/split_files/diffusion_models/wan2.1_t2v_1.3B_bf16.safetensors"
+transformer = WanTransformer3DModel.from_single_file(ckpt_path, torch_dtype=torch.bfloat16)
+
+pipe = WanPipeline.from_pretrained("Wan-AI/Wan2.1-T2V-1.3B-Diffusers", transformer=transformer)
+```
+
 ## WanPipeline
 
 [[autodoc]] WanPipeline

src/diffusers/loaders/single_file_model.py

@@ -39,6 +39,8 @@
     convert_mochi_transformer_checkpoint_to_diffusers,
     convert_sd3_transformer_checkpoint_to_diffusers,
     convert_stable_cascade_unet_single_file_to_diffusers,
+    convert_wan_transformer_to_diffusers,
+    convert_wan_vae_to_diffusers,
     create_controlnet_diffusers_config_from_ldm,
     create_unet_diffusers_config_from_ldm,
     create_vae_diffusers_config_from_ldm,
@@ -117,6 +119,14 @@
         "checkpoint_mapping_fn": convert_lumina2_to_diffusers,
         "default_subfolder": "transformer",
     },
+    "WanTransformer3DModel": {
+        "checkpoint_mapping_fn": convert_wan_transformer_to_diffusers,
+        "default_subfolder": "transformer",
+    },
+    "AutoencoderKLWan": {
+        "checkpoint_mapping_fn": convert_wan_vae_to_diffusers,
+        "default_subfolder": "vae",
+    },
 }