fix: use no-store cache headers to prevent stale frontend chunks

After a frontend update (e.g. nightly build), browsers could load
outdated cached index.html and JS/CSS chunks, causing dynamically
imported modules to fail with MIME type errors and vite:preloadError.

Hard refresh (Ctrl+Shift+R) was insufficient to fix the issue because
Cache-Control: no-cache still allows the browser to cache and
revalidate via ETags. aiohttp's FileResponse auto-generates ETags
based on file mtime+size, which may not change after pip reinstall,
so the browser gets 304 Not Modified and serves stale content.

Clearing ALL site data in DevTools did fix it, confirming the HTTP
cache was the root cause.

The fix changes:
- index.html: no-cache -> no-store, must-revalidate
- JS/CSS/JSON entry points: no-cache -> no-store

no-store instructs browsers to never cache these responses, ensuring
every page load fetches the current index.html with correct chunk
references. This is a small tradeoff (~5KB re-download per page load)
for guaranteed correctness after updates.

comfy/comfy_types/node_typing.py

@@ -176,8 +176,8 @@ class InputTypeOptions(TypedDict):
     """COMBO type only. Specifies the configuration for a multi-select widget.
     Available after ComfyUI frontend v1.13.4
     https://github.com/Comfy-Org/ComfyUI_frontend/pull/2987"""
-    gradient_stops: NotRequired[list[list[float]]]
-    """Gradient color stops for gradientslider display mode. Each stop is [offset, r, g, b] (``FLOAT``)."""
+    gradient_stops: NotRequired[list[dict]]
+    """Gradient color stops for gradientslider display mode. Each stop is {"offset": float, "color": [r, g, b]}."""
 
 
 class HiddenInputTypeDict(TypedDict):

comfy/ldm/flux/model.py

@@ -44,6 +44,22 @@ class FluxParams:
     txt_norm: bool = False
 
 
+def invert_slices(slices, length):
+    sorted_slices = sorted(slices)
+    result = []
+    current = 0
+
+    for start, end in sorted_slices:
+        if current < start:
+            result.append((current, start))
+        current = max(current, end)
+
+    if current < length:
+        result.append((current, length))
+
+    return result
+
+
 class Flux(nn.Module):
     """
     Transformer model for flow matching on sequences.
@@ -138,6 +154,7 @@ class Flux(nn.Module):
         y: Tensor,
         guidance: Tensor = None,
         control = None,
+        timestep_zero_index=None,
         transformer_options={},
         attn_mask: Tensor = None,
     ) -> Tensor:
@@ -164,10 +181,6 @@ class Flux(nn.Module):
             txt = self.txt_norm(txt)
         txt = self.txt_in(txt)
 
-        vec_orig = vec
-        if self.params.global_modulation:
-            vec = (self.double_stream_modulation_img(vec_orig), self.double_stream_modulation_txt(vec_orig))
-
         if "post_input" in patches:
             for p in patches["post_input"]:
                 out = p({"img": img, "txt": txt, "img_ids": img_ids, "txt_ids": txt_ids, "transformer_options": transformer_options})
@@ -182,6 +195,24 @@ class Flux(nn.Module):
         else:
             pe = None
 
+        vec_orig = vec
+        txt_vec = vec
+        extra_kwargs = {}
+        if timestep_zero_index is not None:
+            modulation_dims = []
+            batch = vec.shape[0] // 2
+            vec_orig = vec_orig.reshape(2, batch, vec.shape[1]).movedim(0, 1)
+            invert = invert_slices(timestep_zero_index, img.shape[1])
+            for s in invert:
+                modulation_dims.append((s[0], s[1], 0))
+            for s in timestep_zero_index:
+                modulation_dims.append((s[0], s[1], 1))
+            extra_kwargs["modulation_dims_img"] = modulation_dims
+            txt_vec = vec[:batch]
+
+        if self.params.global_modulation:
+            vec = (self.double_stream_modulation_img(vec_orig), self.double_stream_modulation_txt(txt_vec))
+
         blocks_replace = patches_replace.get("dit", {})
         transformer_options["total_blocks"] = len(self.double_blocks)
         transformer_options["block_type"] = "double"
@@ -195,7 +226,8 @@ class Flux(nn.Module):
                                                    vec=args["vec"],
                                                    pe=args["pe"],
                                                    attn_mask=args.get("attn_mask"),
-                                                   transformer_options=args.get("transformer_options"))
+                                                   transformer_options=args.get("transformer_options"),
+                                                   **extra_kwargs)
                     return out
 
                 out = blocks_replace[("double_block", i)]({"img": img,
@@ -213,7 +245,8 @@ class Flux(nn.Module):
                                  vec=vec,
                                  pe=pe,
                                  attn_mask=attn_mask,
-                                 transformer_options=transformer_options)
+                                 transformer_options=transformer_options,
+                                 **extra_kwargs)
 
             if control is not None: # Controlnet
                 control_i = control.get("input")
@@ -230,6 +263,12 @@ class Flux(nn.Module):
         if self.params.global_modulation:
             vec, _ = self.single_stream_modulation(vec_orig)
 
+        extra_kwargs = {}
+        if timestep_zero_index is not None:
+            lambda a: 0 if a == 0 else a + txt.shape[1]
+            modulation_dims_combined = list(map(lambda x: (0 if x[0] == 0 else x[0] + txt.shape[1], x[1] + txt.shape[1], x[2]), modulation_dims))
+            extra_kwargs["modulation_dims"] = modulation_dims_combined
+
         transformer_options["total_blocks"] = len(self.single_blocks)
         transformer_options["block_type"] = "single"
         transformer_options["img_slice"] = [txt.shape[1], img.shape[1]]
@@ -242,7 +281,8 @@ class Flux(nn.Module):
                                        vec=args["vec"],
                                        pe=args["pe"],
                                        attn_mask=args.get("attn_mask"),
-                                       transformer_options=args.get("transformer_options"))
+                                       transformer_options=args.get("transformer_options"),
+                                       **extra_kwargs)
                     return out
 
                 out = blocks_replace[("single_block", i)]({"img": img,
@@ -253,7 +293,7 @@ class Flux(nn.Module):
                                                           {"original_block": block_wrap})
                 img = out["img"]
             else:
-                img = block(img, vec=vec, pe=pe, attn_mask=attn_mask, transformer_options=transformer_options)
+                img = block(img, vec=vec, pe=pe, attn_mask=attn_mask, transformer_options=transformer_options, **extra_kwargs)
 
             if control is not None: # Controlnet
                 control_o = control.get("output")
@@ -264,7 +304,11 @@ class Flux(nn.Module):
 
         img = img[:, txt.shape[1] :, ...]
 
-        img = self.final_layer(img, vec_orig)  # (N, T, patch_size ** 2 * out_channels)
+        extra_kwargs = {}
+        if timestep_zero_index is not None:
+            extra_kwargs["modulation_dims"] = modulation_dims
+
+        img = self.final_layer(img, vec_orig, **extra_kwargs)  # (N, T, patch_size ** 2 * out_channels)
         return img
 
     def process_img(self, x, index=0, h_offset=0, w_offset=0, transformer_options={}):
@@ -312,13 +356,16 @@ class Flux(nn.Module):
         w_len = ((w_orig + (patch_size // 2)) // patch_size)
         img, img_ids = self.process_img(x, transformer_options=transformer_options)
         img_tokens = img.shape[1]
+        timestep_zero_index = None
         if ref_latents is not None:
+            ref_num_tokens = []
             h = 0
             w = 0
             index = 0
             ref_latents_method = kwargs.get("ref_latents_method", self.params.default_ref_method)
+            timestep_zero = ref_latents_method == "index_timestep_zero"
             for ref in ref_latents:
-                if ref_latents_method == "index":
+                if ref_latents_method in ("index", "index_timestep_zero"):
                     index += self.params.ref_index_scale
                     h_offset = 0
                     w_offset = 0
@@ -342,6 +389,13 @@ class Flux(nn.Module):
                 kontext, kontext_ids = self.process_img(ref, index=index, h_offset=h_offset, w_offset=w_offset)
                 img = torch.cat([img, kontext], dim=1)
                 img_ids = torch.cat([img_ids, kontext_ids], dim=1)
+                ref_num_tokens.append(kontext.shape[1])
+            if timestep_zero:
+                if index > 0:
+                    timestep = torch.cat([timestep, timestep * 0], dim=0)
+                    timestep_zero_index = [[img_tokens, img_ids.shape[1]]]
+            transformer_options = transformer_options.copy()
+            transformer_options["reference_image_num_tokens"] = ref_num_tokens
 
         txt_ids = torch.zeros((bs, context.shape[1], len(self.params.axes_dim)), device=x.device, dtype=torch.float32)
 
@@ -349,6 +403,6 @@ class Flux(nn.Module):
             for i in self.params.txt_ids_dims:
                 txt_ids[:, :, i] = torch.linspace(0, context.shape[1] - 1, steps=context.shape[1], device=x.device, dtype=torch.float32)
 
-        out = self.forward_orig(img, img_ids, context, txt_ids, timestep, y, guidance, control, transformer_options, attn_mask=kwargs.get("attention_mask", None))
+        out = self.forward_orig(img, img_ids, context, txt_ids, timestep, y, guidance, control, timestep_zero_index=timestep_zero_index, transformer_options=transformer_options, attn_mask=kwargs.get("attention_mask", None))
         out = out[:, :img_tokens]
         return rearrange(out, "b (h w) (c ph pw) -> b c (h ph) (w pw)", h=h_len, w=w_len, ph=self.patch_size, pw=self.patch_size)[:,:,:h_orig,:w_orig]

comfy_api/latest/_io.py

@@ -297,7 +297,7 @@ class Float(ComfyTypeIO):
         '''Float input.'''
         def __init__(self, id: str, display_name: str=None, optional=False, tooltip: str=None, lazy: bool=None,
                     default: float=None, min: float=None, max: float=None, step: float=None, round: float=None,
-                    display_mode: NumberDisplay=None, gradient_stops: list[list[float]]=None,
+                    display_mode: NumberDisplay=None, gradient_stops: list[dict]=None,
                     socketless: bool=None, force_input: bool=None, extra_dict=None, raw_link: bool=None, advanced: bool=None):
             super().__init__(id, display_name, optional, tooltip, lazy, default, socketless, None, force_input, extra_dict, raw_link, advanced)
             self.min = min

comfy_extras/nodes_flux.py

@@ -6,6 +6,7 @@ import comfy.model_management
 import torch
 import math
 import nodes
+import comfy.ldm.flux.math
 
 class CLIPTextEncodeFlux(io.ComfyNode):
     @classmethod
@@ -231,6 +232,68 @@ class Flux2Scheduler(io.ComfyNode):
         sigmas = get_schedule(steps, round(seq_len))
         return io.NodeOutput(sigmas)
 
+class KV_Attn_Input:
+    def __init__(self):
+        self.cache = {}
+
+    def __call__(self, q, k, v, extra_options, **kwargs):
+        reference_image_num_tokens = extra_options.get("reference_image_num_tokens", [])
+        if len(reference_image_num_tokens) == 0:
+            return {}
+
+        ref_toks = sum(reference_image_num_tokens)
+        cache_key = "{}_{}".format(extra_options["block_type"], extra_options["block_index"])
+        if cache_key in self.cache:
+            kk, vv = self.cache[cache_key]
+            self.set_cache = False
+            return {"q": q, "k": torch.cat((k, kk), dim=2), "v": torch.cat((v, vv), dim=2)}
+
+        self.cache[cache_key] = (k[:, :, -ref_toks:].clone(), v[:, :, -ref_toks:].clone())
+        self.set_cache = True
+        return {"q": q, "k": k, "v": v}
+
+    def cleanup(self):
+        self.cache = {}
+
+
+class FluxKVCache(io.ComfyNode):
+    @classmethod
+    def define_schema(cls) -> io.Schema:
+        return io.Schema(
+            node_id="FluxKVCache",
+            display_name="Flux KV Cache",
+            description="Enables KV Cache optimization for reference images on Flux family models.",
+            category="",
+            is_experimental=True,
+            inputs=[
+                io.Model.Input("model", tooltip="The model to use KV Cache on."),
+            ],
+            outputs=[
+                io.Model.Output(tooltip="The patched model with KV Cache enabled."),
+            ],
+        )
+
+    @classmethod
+    def execute(cls, model: io.Model.Type) -> io.NodeOutput:
+        m = model.clone()
+        input_patch_obj = KV_Attn_Input()
+
+        def model_input_patch(inputs):
+            if len(input_patch_obj.cache) > 0:
+                ref_image_tokens = sum(inputs["transformer_options"].get("reference_image_num_tokens", []))
+                if ref_image_tokens > 0:
+                    img = inputs["img"]
+                    inputs["img"] = img[:, :-ref_image_tokens]
+            return inputs
+
+        m.set_model_attn1_patch(input_patch_obj)
+        m.set_model_post_input_patch(model_input_patch)
+        if hasattr(model.model.diffusion_model, "params"):
+            m.add_object_patch("diffusion_model.params.default_ref_method", "index_timestep_zero")
+        else:
+            m.add_object_patch("diffusion_model.default_ref_method", "index_timestep_zero")
+
+        return io.NodeOutput(m)
 
 class FluxExtension(ComfyExtension):
     @override
@@ -243,6 +306,7 @@ class FluxExtension(ComfyExtension):
             FluxKontextMultiReferenceLatentMethod,
             EmptyFlux2LatentImage,
             Flux2Scheduler,
+            FluxKVCache,
         ]
 
 

comfy_extras/nodes_painter.py

@@ -0,0 +1,127 @@
+from __future__ import annotations
+
+import hashlib
+import os
+
+import numpy as np
+import torch
+from PIL import Image
+
+import folder_paths
+import node_helpers
+from comfy_api.latest import ComfyExtension, io, UI
+from typing_extensions import override
+
+
+def hex_to_rgb(hex_color: str) -> tuple[float, float, float]:
+    hex_color = hex_color.lstrip("#")
+    if len(hex_color) != 6:
+        return (0.0, 0.0, 0.0)
+    r = int(hex_color[0:2], 16) / 255.0
+    g = int(hex_color[2:4], 16) / 255.0
+    b = int(hex_color[4:6], 16) / 255.0
+    return (r, g, b)
+
+
+class PainterNode(io.ComfyNode):
+    @classmethod
+    def define_schema(cls):
+        return io.Schema(
+            node_id="Painter",
+            display_name="Painter",
+            category="image",
+            inputs=[
+                io.Image.Input(
+                    "image",
+                    optional=True,
+                    tooltip="Optional base image to paint over",
+                ),
+                io.String.Input(
+                    "mask",
+                    default="",
+                    socketless=True,
+                    extra_dict={"widgetType": "PAINTER", "image_upload": True},
+                ),
+                io.Int.Input(
+                    "width",
+                    default=512,
+                    min=64,
+                    max=4096,
+                    step=64,
+                    socketless=True,
+                    extra_dict={"hidden": True},
+                ),
+                io.Int.Input(
+                    "height",
+                    default=512,
+                    min=64,
+                    max=4096,
+                    step=64,
+                    socketless=True,
+                    extra_dict={"hidden": True},
+                ),
+                io.Color.Input("bg_color", default="#000000"),
+            ],
+            outputs=[
+                io.Image.Output("IMAGE"),
+                io.Mask.Output("MASK"),
+            ],
+        )
+
+    @classmethod
+    def execute(cls, mask, width, height, bg_color="#000000", image=None) -> io.NodeOutput:
+        if image is not None:
+            base_image = image[:1]
+            h, w = base_image.shape[1], base_image.shape[2]
+        else:
+            h, w = height, width
+            r, g, b = hex_to_rgb(bg_color)
+            base_image = torch.zeros((1, h, w, 3), dtype=torch.float32)
+            base_image[0, :, :, 0] = r
+            base_image[0, :, :, 1] = g
+            base_image[0, :, :, 2] = b
+
+        if mask and mask.strip():
+            mask_path = folder_paths.get_annotated_filepath(mask)
+            painter_img = node_helpers.pillow(Image.open, mask_path)
+            painter_img = painter_img.convert("RGBA")
+
+            if painter_img.size != (w, h):
+                painter_img = painter_img.resize((w, h), Image.LANCZOS)
+
+            painter_np = np.array(painter_img).astype(np.float32) / 255.0
+            painter_rgb = painter_np[:, :, :3]
+            painter_alpha = painter_np[:, :, 3:4]
+
+            mask_tensor = torch.from_numpy(painter_np[:, :, 3]).unsqueeze(0)
+
+            base_np = base_image[0].cpu().numpy()
+            composited = painter_rgb * painter_alpha + base_np * (1.0 - painter_alpha)
+            out_image = torch.from_numpy(composited).unsqueeze(0)
+        else:
+            mask_tensor = torch.zeros((1, h, w), dtype=torch.float32)
+            out_image = base_image
+
+        return io.NodeOutput(out_image, mask_tensor, ui=UI.PreviewImage(out_image))
+
+    @classmethod
+    def fingerprint_inputs(cls, mask, width, height, bg_color="#000000", image=None):
+        if mask and mask.strip():
+            mask_path = folder_paths.get_annotated_filepath(mask)
+            if os.path.exists(mask_path):
+                m = hashlib.sha256()
+                with open(mask_path, "rb") as f:
+                    m.update(f.read())
+                return m.digest().hex()
+        return ""
+
+
+
+class PainterExtension(ComfyExtension):
+    @override
+    async def get_node_list(self):
+        return [PainterNode]
+
+
+async def comfy_entrypoint():
+    return PainterExtension()

middleware/cache_middleware.py

@@ -32,7 +32,7 @@ async def cache_control(
     )
 
     if request.path.endswith(".js") or request.path.endswith(".css") or is_entry_point:
-        response.headers.setdefault("Cache-Control", "no-cache")
+        response.headers.setdefault("Cache-Control", "no-store")
         return response
 
     # Early return for non-image files - no cache headers needed

nodes.py

@@ -951,7 +951,7 @@ class UNETLoader:
     @classmethod
     def INPUT_TYPES(s):
         return {"required": { "unet_name": (folder_paths.get_filename_list("diffusion_models"), ),
-                              "weight_dtype": (["default", "fp8_e4m3fn", "fp8_e4m3fn_fast", "fp8_e5m2"], {"advanced": True})
+                              "weight_dtype": (["default", "fp8_e4m3fn", "fp8_e4m3fn_fast", "fp8_e5m2"],)
                              }}
     RETURN_TYPES = ("MODEL",)
     FUNCTION = "load_unet"
@@ -2450,6 +2450,7 @@ async def init_builtin_extra_nodes():
         "nodes_nag.py",
         "nodes_sdpose.py",
         "nodes_math.py",
+        "nodes_painter.py",
     ]
 
     import_failed = []

requirements.txt

@@ -1,5 +1,5 @@
-comfyui-frontend-package==1.41.16
-comfyui-workflow-templates==0.9.18
+comfyui-frontend-package==1.41.18
+comfyui-workflow-templates==0.9.21
 comfyui-embedded-docs==0.4.3
 torch
 torchsde

server.py

@@ -310,7 +310,7 @@ class PromptServer():
         @routes.get("/")
         async def get_root(request):
             response = web.FileResponse(os.path.join(self.web_root, "index.html"))
-            response.headers['Cache-Control'] = 'no-cache'
+            response.headers['Cache-Control'] = 'no-store, must-revalidate'
             response.headers["Pragma"] = "no-cache"
             response.headers["Expires"] = "0"
             return response

tests-unit/server_test/test_cache_control.py

@@ -28,31 +28,31 @@ CACHE_SCENARIOS = [
     },
     # JavaScript/CSS scenarios
     {
-        "name": "js_no_cache",
+        "name": "js_no_store",
         "path": "/script.js",
         "status": 200,
-        "expected_cache": "no-cache",
+        "expected_cache": "no-store",
         "should_have_header": True,
     },
     {
-        "name": "css_no_cache",
+        "name": "css_no_store",
         "path": "/styles.css",
         "status": 200,
-        "expected_cache": "no-cache",
+        "expected_cache": "no-store",
         "should_have_header": True,
     },
     {
-        "name": "index_json_no_cache",
+        "name": "index_json_no_store",
         "path": "/api/index.json",
         "status": 200,
-        "expected_cache": "no-cache",
+        "expected_cache": "no-store",
         "should_have_header": True,
     },
     {
-        "name": "localized_index_json_no_cache",
+        "name": "localized_index_json_no_store",
         "path": "/templates/index.zh.json",
         "status": 200,
-        "expected_cache": "no-cache",
+        "expected_cache": "no-store",
         "should_have_header": True,
     },
     # Non-matching files