[Single File] Support loading Comfy UI Flux checkpoints (#9243)

update

src/diffusers/loaders/single_file_utils.py

@@ -79,7 +79,10 @@
     "animatediff_sdxl_beta": "up_blocks.2.motion_modules.0.temporal_transformer.norm.weight",
     "animatediff_scribble": "controlnet_cond_embedding.conv_in.weight",
     "animatediff_rgb": "controlnet_cond_embedding.weight",
-    "flux": "double_blocks.0.img_attn.norm.key_norm.scale",
+    "flux": [
+        "double_blocks.0.img_attn.norm.key_norm.scale",
+        "model.diffusion_model.double_blocks.0.img_attn.norm.key_norm.scale",
+    ],
 }
 
 DIFFUSERS_DEFAULT_PIPELINE_PATHS = {
@@ -258,7 +261,7 @@
     "timestep_spacing": "leading",
 }
 
-LDM_VAE_KEY = "first_stage_model."
+LDM_VAE_KEYS = ["first_stage_model.", "vae."]
 LDM_VAE_DEFAULT_SCALING_FACTOR = 0.18215
 PLAYGROUND_VAE_SCALING_FACTOR = 0.5
 LDM_UNET_KEY = "model.diffusion_model."
@@ -267,7 +270,6 @@
     "cond_stage_model.transformer.",
     "conditioner.embedders.0.transformer.",
 ]
-OPEN_CLIP_PREFIX = "conditioner.embedders.0.model."
 LDM_OPEN_CLIP_TEXT_PROJECTION_DIM = 1024
 SCHEDULER_LEGACY_KWARGS = ["prediction_type", "scheduler_type"]
 
@@ -523,8 +525,10 @@ def infer_diffusers_model_type(checkpoint):
         else:
             model_type = "animatediff_v3"
 
-    elif CHECKPOINT_KEY_NAMES["flux"] in checkpoint:
-        if "guidance_in.in_layer.bias" in checkpoint:
+    elif any(key in checkpoint for key in CHECKPOINT_KEY_NAMES["flux"]):
+        if any(
+            g in checkpoint for g in ["guidance_in.in_layer.bias", "model.diffusion_model.guidance_in.in_layer.bias"]
+        ):
             model_type = "flux-dev"
         else:
             model_type = "flux-schnell"
@@ -1183,7 +1187,11 @@ def convert_ldm_vae_checkpoint(checkpoint, config):
     # remove the LDM_VAE_KEY prefix from the ldm checkpoint keys so that it is easier to map them to diffusers keys
     vae_state_dict = {}
     keys = list(checkpoint.keys())
-    vae_key = LDM_VAE_KEY if any(k.startswith(LDM_VAE_KEY) for k in keys) else ""
+    vae_key = ""
+    for ldm_vae_key in LDM_VAE_KEYS:
+        if any(k.startswith(ldm_vae_key) for k in keys):
+            vae_key = ldm_vae_key
+
     for key in keys:
         if key.startswith(vae_key):
             vae_state_dict[key.replace(vae_key, "")] = checkpoint.get(key)
@@ -1896,6 +1904,10 @@ def convert_animatediff_checkpoint_to_diffusers(checkpoint, **kwargs):
 
 def convert_flux_transformer_checkpoint_to_diffusers(checkpoint, **kwargs):
     converted_state_dict = {}
+    keys = list(checkpoint.keys())
+    for k in keys:
+        if "model.diffusion_model." in k:
+            checkpoint[k.replace("model.diffusion_model.", "")] = checkpoint.pop(k)
 
     num_layers = list(set(int(k.split(".", 2)[1]) for k in checkpoint if "double_blocks." in k))[-1] + 1  # noqa: C401
     num_single_layers = list(set(int(k.split(".", 2)[1]) for k in checkpoint if "single_blocks." in k))[-1] + 1  # noqa: C401