ComfyUI with comfy-kitchen fails to start on PyTorch < 2.7 (for legacy GPUs)

### Custom Node Testing

- [x] I have tried disabling custom nodes and the issue persists (see [how to disable custom nodes](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled) if you need help)

### Expected Behavior

Automatic launch of the ComfyUI backend when the launch script for SwarmUI is run

Environment that triggered the issue:

SwarmUI 0.9.8.2 (self-starting ComfyUI backend)
GPU: GTX 1050 4 GB
PyTorch 2.4.1 + CUDA 12.1
Date of first breakage: 2026-08-08

### Actual Behavior

Failure to launch the backend due to a failure to import comfy-kitchen (see log)

### Steps to Reproduce

1. Install / update to a recent ComfyUI that depends on comfy-kitchen ≥ 0.2.28
2. Have PyTorch 2.4.x / 2.5.x / 2.6.x
3. Launch → immediate crash on "import comfy_kitchen"

### Debug Logs

```powershell
2026-08-08 17:23:56.879 [Init] === SwarmUI v0.9.8.2 Starting at 2026-08-08 17:23:56 ===
2026-08-08 17:23:56.890 [Init] Parsing command line...
2026-08-08 17:23:56.906 [Init] Loading settings file...
2026-08-08 17:23:56.945 [Init] Re-saving settings file...
2026-08-08 17:23:56.980 [Init] Applying command line settings...
2026-08-08 17:23:56.991 [Init] SwarmUI was installed 2025-02-05 (18 months ago) with version 0.9.5.0
2026-08-08 17:23:56.991 [Init] Swarm base path is: /home/user/swarmui/SwarmUI
2026-08-08 17:23:56.991 [Init] Running on OS: Manjaro Linux
2026-08-08 17:23:56.992 [Debug] [Load Time] Initial settings load took 0.1s (0.1s from start)
2026-08-08 17:23:57.037 [Init] Prepping extension: SwarmUI.Builtin_ImageBatchToolExtension.ImageBatchToolExtension...
2026-08-08 17:23:57.038 [Init] Prepping extension: SwarmUI.Builtin_GridGeneratorExtension.GridGeneratorExtension...
2026-08-08 17:23:57.038 [Init] Prepping extension: SwarmUI.Builtin_DynamicThresholding.DynamicThresholdingExtension...
2026-08-08 17:23:57.038 [Init] Prepping extension: SwarmUI.Builtin_ComfyUIBackend.ComfyUIBackendExtension...
2026-08-08 17:23:57.038 [Init] Prepping extension: SwarmUI.Builtin_AutoWebUIExtension.AutoWebUIBackendExtension...
2026-08-08 17:23:57.087 [Debug] Don't need to rebuild extension src/Extensions/SwarmUI-FaceTools/SwarmUI-FaceTools.csproj, already built.
2026-08-08 17:23:57.091 [Debug] Don't need to rebuild extension src/Extensions/SwarmUI-PromptBuilderExtension/SwarmAutoGenExtensionProjectFile.csproj, already built.
2026-08-08 17:23:57.093 [Init] Prepping extension: Quaggles.Extensions.FaceTools.FaceToolsExtension...
2026-08-08 17:23:57.093 [Init] Prepping extension: PromptBuilderExtension.PromptBuilderExtension...
2026-08-08 17:23:57.109 [Init] CPU Cores: 4 | RAM: 23.35 GiB total, 20.39 GiB available, unknown virtual/swap
2026-08-08 17:23:57.109 [Init] Current git commit is [28905519: tweak h3 lora detect], marked as date 2026-08-08 10:48:24 (5 hours ago)
2026-08-08 17:23:57.126 [Init] GPU 0: NVIDIA GeForce GTX 1050 | Temp 44C | Util 0% GPU, 0% Memory | VRAM 4.00 GiB total, 3.93 GiB free, 12.00 MiB used
2026-08-08 17:23:57.146 [Info] Loaded Prompt Builder data category: Background
2026-08-08 17:23:57.146 [Info] Loaded Prompt Builder data category: Colors
2026-08-08 17:23:57.148 [Info] Loaded Prompt Builder data category: Image Composition
2026-08-08 17:23:57.154 [Info] Loaded Prompt Builder data category: Character
2026-08-08 17:23:57.155 [Info] Loaded Prompt Builder data category: Lighting
2026-08-08 17:23:57.155 [Info] Loaded Prompt Builder data category: Locations
2026-08-08 17:23:57.155 [Info] Loaded Prompt Builder data category: Sex
2026-08-08 17:23:57.156 [Info] Loaded Prompt Builder data category: Creatures
2026-08-08 17:23:57.157 [Info] Loaded Prompt Builder data category: Design Elements
2026-08-08 17:23:57.158 [Info] Loaded Prompt Builder data category: Games
2026-08-08 17:23:57.158 [Info] Loaded Prompt Builder data category: Groups
2026-08-08 17:23:57.158 [Info] Loaded Prompt Builder data category: Jobs
2026-08-08 17:23:57.160 [Info] Loaded Prompt Builder data category: Objects
2026-08-08 17:23:57.160 [Info] Loaded Prompt Builder data category: Plants
2026-08-08 17:23:57.181 [Info] Loaded Prompt Builder data category: Series
2026-08-08 17:23:57.181 [Info] Prompt Builder Extension loaded 15 data categories
2026-08-08 17:23:57.183 [Debug] [Load Time] Extension PreInit took 0.19s (0.3s from start)
2026-08-08 17:23:57.183 [Init] Prepping options...
2026-08-08 17:23:57.323 [Debug] [Load Time] Prep Options took 0.14s (0.44s from start)
2026-08-08 17:23:57.324 [Debug] [Load Time] Web PreInit took 0s (0.44s from start)
2026-08-08 17:23:57.346 [Debug] [Load Time] Extensions Init took 0.02s (0.46s from start)
2026-08-08 17:23:57.346 [Debug] [Load Time] Prep Utils took 0s (0.46s from start)
2026-08-08 17:23:57.375 [Debug] [Load Time] Languages load took 0.03s (0.49s from start)
2026-08-08 17:23:57.375 [Init] Loading models list...
2026-08-08 17:23:57.398 [Debug] Have 14 Stable-Diffusion models.
2026-08-08 17:23:57.400 [Debug] Have 3 VAE models.
2026-08-08 17:23:57.414 [Debug] Have 65 LoRA models.
2026-08-08 17:23:57.415 [Debug] Have 6 Embedding models.
2026-08-08 17:23:57.418 [Debug] Have 19 ControlNet models.
2026-08-08 17:23:57.418 [Debug] Have 0 Clip models.
2026-08-08 17:23:57.418 [Debug] Have 0 ClipVision models.
2026-08-08 17:23:57.420 [Debug] [Load Time] Model listing took 0.05s (0.53s from start)
2026-08-08 17:23:57.420 [Init] Loading backends...
2026-08-08 17:23:57.421 [Init] Loading backends from file...
2026-08-08 17:23:57.423 [Debug] [Load ComfyUI Self-Starting #0] Waiting to load...
2026-08-08 17:23:57.425 [Debug] [Load ComfyUI Self-Starting #0] Will now load...
2026-08-08 17:23:57.425 [Init] Initializing backend #0 - ComfyUI Self-Starting...
2026-08-08 17:23:57.426 [Debug] [Load Time] Backends took 0.01s (0.54s from start)
2026-08-08 17:23:57.426 [Init] Prepping API...
2026-08-08 17:23:57.427 [Debug] [Load ComfyUI Self-Starting #0] Starting init...
2026-08-08 17:23:57.428 [Debug] [Load ComfyUI Self-Starting #0] Will emit comfy model paths file...
2026-08-08 17:23:57.428 [Debug] [Load ComfyUI Self-Starting #0] Done emitting comfy model paths file.
2026-08-08 17:23:57.428 [Debug] [Load ComfyUI Self-Starting #0] Will add args: --extra-model-paths-config /home/user/swarmui/SwarmUI/Data/comfy-auto-model.yaml --preview-method latent2rgb --front-end-version Comfy-Org/ComfyUI_frontend@v1.47.12
2026-08-08 17:23:57.429 [Debug] [Load ComfyUI Self-Starting #0] Will track node repo load task...
2026-08-08 17:23:57.429 [Debug] [Load ComfyUI Self-Starting #0] Waiting on git tasks to complete...
2026-08-08 17:23:57.431 [Debug] [Load Time] API took 0.01s (0.54s from start)
2026-08-08 17:23:57.431 [Init] Prepping webserver...
2026-08-08 17:23:57.436 [Init] Backend request handler loop ready...
2026-08-08 17:23:57.465 [Debug] [Load Time] [Web] WebApp builder prep took 0.03s (0.03s from start)
2026-08-08 17:23:57.481 [Debug] [Load ComfyUI Self-Starting #0] Will ensure all node repos...
2026-08-08 17:23:57.510 [Debug] [Load Time] [Web] WebApp build took 0.05s (0.07s from start)
2026-08-08 17:23:57.510 [Debug] [Load Time] [Web] exception handler took 0s (0.08s from start)
2026-08-08 17:23:57.510 [Debug] [Load Time] [Web] StartStop handler took 0s (0.08s from start)
2026-08-08 17:23:57.510 [Debug] [Load Time] [Web] static files took 0s (0.08s from start)
2026-08-08 17:23:57.533 [Debug] [Load ComfyUI Self-Starting #0] Ensure node repos - Will git pull for ComfyUI_IPAdapter_plus...
2026-08-08 17:23:57.582 [Debug] [Load ComfyUI Self-Starting #0] Ensure node repos - Will git pull for ComfyUI-SAI_API...
2026-08-08 17:23:57.617 [Debug] [Load Time] [Web] core use calls took 0.11s (0.18s from start)
2026-08-08 17:23:57.620 [Debug] [Load Time] [Web] core maps took 0s (0.19s from start)
2026-08-08 17:23:57.620 [Init] Scan for web extensions...
2026-08-08 17:23:57.622 [Debug] [Load Time] [Web] end took 0s (0.19s from start)
2026-08-08 17:23:57.622 [Debug] [Load Time] Web prep took 0.19s (0.74s from start)
2026-08-08 17:23:57.622 [Init] Readying extensions for launch...
2026-08-08 17:23:57.622 [Debug] [Load Time] Extensions pre-launch took 0s (0.74s from start)
2026-08-08 17:23:57.622 [Init] Launching server...
2026-08-08 17:23:57.624 [Init] Starting webserver on http://localhost:7801
2026-08-08 17:23:57.680 [Debug] [Load Time] Web launch took 0.06s (0.79s from start)
2026-08-08 17:23:58.013 [Debug] [Load ComfyUI Self-Starting #0] Node pull response for ComfyUI-SAI_API: Already up to date.
2026-08-08 17:23:58.031 [Debug] [Load ComfyUI Self-Starting #0] Node pull response for ComfyUI_IPAdapter_plus: Already up to date.
2026-08-08 17:23:58.031 [Debug] [Load ComfyUI Self-Starting #0] Done ensuring all node repos.
2026-08-08 17:23:58.031 [Debug] [Load ComfyUI Self-Starting #0] All tasks done.
2026-08-08 17:23:58.036 [Init] Swarm is up to date! You have version 0.9.8.2, and 0.9.8-Beta is the latest.
2026-08-08 17:23:58.036 [Init] SwarmUI v0.9.8.2 - Local is now running.
2026-08-08 17:23:58.039 [Debug] [Load ComfyUI Self-Starting #0] Will validate required libs...
2026-08-08 17:23:58.042 [Debug] [Load ComfyUI Self-Starting #0] Done validating required libs.
2026-08-08 17:23:58.042 [Debug] [Load ComfyUI Self-Starting #0] Starting self-start ComfyUI process...
2026-08-08 17:23:58.044 [Debug] [Load ComfyUI Self-Starting #0] Requested generic launch of dlbackend/ComfyUI/main.py on GPU 0 from ComfyUI-0
2026-08-08 17:23:58.049 [Debug] (ComfyUI-0 launch) Adding path /home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv
2026-08-08 17:23:58.049 [Debug] [Load ComfyUI Self-Starting #0] (ComfyUI-0 launch) Will use python: /home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/bin/python3
2026-08-08 17:23:58.049 [Debug] [Load ComfyUI Self-Starting #0] Will start process...
2026-08-08 17:23:58.049 [Init] Self-Start ComfyUI-0 on port 7821 is loading...
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path checkpoints /home/user/stable-diffusion-webui/models/Stable-diffusion
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path vae /home/user/stable-diffusion-webui/models/VAE
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path loras /home/user/stable-diffusion-webui/models/Lora
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path loras /home/user/stable-diffusion-webui/models/LyCORIS
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/ESRGAN
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/RealESRGAN
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/SwinIR
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/upscale-models
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/upscale_models
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path embeddings /home/user/stable-diffusion-webui/embeddings
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path embeddings /home/user/stable-diffusion-webui/models/embeddings
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path hypernetworks /home/user/stable-diffusion-webui/models/hypernetworks
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path controlnet /home/user/stable-diffusion-webui/models/ControlNet
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path model_patches /home/user/stable-diffusion-webui/models/ControlNet
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path model_patches /home/user/stable-diffusion-webui/models/model_patches
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path clip /home/user/stable-diffusion-webui/models/clip
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path clip /home/user/stable-diffusion-webui/models/CLIP
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path clip_vision /home/user/stable-diffusion-webui/models/clip_vision
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path unet /home/user/stable-diffusion-webui/models/unet
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path diffusion_models /home/user/stable-diffusion-webui/models/diffusion_models
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path gligen /home/user/stable-diffusion-webui/models/gligen
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path ipadapter /home/user/stable-diffusion-webui/models/ipadapter
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path yolov8 /home/user/stable-diffusion-webui/models/yolov8
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path tensorrt /home/user/stable-diffusion-webui/models/tensorrt
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path clipseg /home/user/stable-diffusion-webui/models/clipseg
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path style_models /home/user/stable-diffusion-webui/models/style_models
2026-08-08 17:23:58.468 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path latent_upscale_models /home/user/stable-diffusion-webui/models/latent_upscale_models
2026-08-08 17:23:58.469 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path custom_nodes /home/user/swarmui/SwarmUI/src/BuiltinExtensions/ComfyUIBackend/DLNodes
2026-08-08 17:23:58.469 [Debug] [ComfyUI-0/STDERR] [INFO] Adding extra search path custom_nodes /home/user/swarmui/SwarmUI/src/BuiltinExtensions/ComfyUIBackend/ExtraNodes
2026-08-08 17:23:58.536 [Init] Launch web browser...
2026-08-08 17:23:59.054 [Debug] [Load ComfyUI Self-Starting #0] Will attempt to load value set...
2026-08-08 17:23:59.659 [Debug] [ComfyUI-0/STDOUT] [START] Security scan
2026-08-08 17:23:59.659 [Debug] [ComfyUI-0/STDOUT] [DONE] Security scan
2026-08-08 17:23:59.659 [Debug] [ComfyUI-0/STDOUT] ## ComfyUI-Manager: installing dependencies done.
2026-08-08 17:23:59.659 [Debug] [ComfyUI-0/STDOUT] ** ComfyUI startup time: 2026-08-08 17:23:59.659
2026-08-08 17:23:59.659 [Debug] [ComfyUI-0/STDOUT] ** Platform: Linux
2026-08-08 17:23:59.660 [Debug] [ComfyUI-0/STDOUT] ** Python version: 3.11.11 (main, Dec 11 2024, 16:28:39) [GCC 11.2.0]
2026-08-08 17:23:59.660 [Debug] [ComfyUI-0/STDOUT] ** Python executable: /home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/bin/python3
2026-08-08 17:23:59.660 [Debug] [ComfyUI-0/STDOUT] ** ComfyUI Path: /home/user/swarmui/SwarmUI/dlbackend/ComfyUI
2026-08-08 17:23:59.660 [Debug] [ComfyUI-0/STDOUT] ** ComfyUI Base Folder Path: /home/user/swarmui/SwarmUI/dlbackend/ComfyUI
2026-08-08 17:23:59.660 [Debug] [ComfyUI-0/STDOUT] ** User directory: /home/user/swarmui/SwarmUI/dlbackend/ComfyUI/user
2026-08-08 17:23:59.660 [Debug] [ComfyUI-0/STDOUT] ** ComfyUI-Manager config path: /home/user/swarmui/SwarmUI/dlbackend/ComfyUI/user/default/ComfyUI-Manager/config.ini
2026-08-08 17:23:59.660 [Debug] [ComfyUI-0/STDOUT] ** Log path: /home/user/swarmui/SwarmUI/dlbackend/ComfyUI/user/comfyui.log
2026-08-08 17:24:00.085 [Debug] [Load ComfyUI Self-Starting #0] Will attempt to load value set...
2026-08-08 17:24:01.088 [Debug] [Load ComfyUI Self-Starting #0] Will attempt to load value set...
2026-08-08 17:24:02.091 [Debug] [Load ComfyUI Self-Starting #0] Will attempt to load value set...
2026-08-08 17:24:03.092 [Debug] [Load ComfyUI Self-Starting #0] Will attempt to load value set...
2026-08-08 17:24:03.172 [Warning] [ComfyUI-0/STDERR] Traceback (most recent call last):
2026-08-08 17:24:03.172 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/main.py", line 237, in
2026-08-08 17:24:03.172 [Warning] [ComfyUI-0/STDERR] import comfy.utils
2026-08-08 17:24:03.173 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/comfy/utils.py", line 25, in
2026-08-08 17:24:03.173 [Warning] [ComfyUI-0/STDERR] import comfy.memory_management
2026-08-08 17:24:03.173 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/comfy/memory_management.py", line 8, in
2026-08-08 17:24:03.173 [Warning] [ComfyUI-0/STDERR] from comfy.quant_ops import QuantizedTensor
2026-08-08 17:24:03.173 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/comfy/quant_ops.py", line 23, in
2026-08-08 17:24:03.174 [Warning] [ComfyUI-0/STDERR] import comfy_kitchen as ck
2026-08-08 17:24:03.174 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/comfy_kitchen/**init**.py", line 3, in
2026-08-08 17:24:03.174 [Warning] [ComfyUI-0/STDERR] from .backends import cuda as _cuda_backend # noqa: F401
2026-08-08 17:24:03.175 [Warning] [ComfyUI-0/STDERR] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-08-08 17:24:03.176 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/comfy_kitchen/backends/cuda/**init**.py", line 161, in
2026-08-08 17:24:03.176 [Warning] [ComfyUI-0/STDERR] from comfy_kitchen.backends.eager import rope as _eager_rope # noqa: E402
2026-08-08 17:24:03.178 [Warning] [ComfyUI-0/STDERR] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-08-08 17:24:03.178 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/comfy_kitchen/backends/eager/**init**.py", line 71, in
2026-08-08 17:24:03.178 [Warning] [ComfyUI-0/STDERR] from .na import na3d
2026-08-08 17:24:03.178 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/comfy_kitchen/backends/eager/na.py", line 163, in
2026-08-08 17:24:03.179 [Warning] [ComfyUI-0/STDERR] @torch.library.custom_op("comfy_kitchen::na3d", mutates_args=())
2026-08-08 17:24:03.181 [Warning] [ComfyUI-0/STDERR] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-08-08 17:24:03.181 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/torch/_library/custom_ops.py", line 119, in inner
2026-08-08 17:24:03.181 [Warning] [ComfyUI-0/STDERR] schema_str = torch._custom_op.impl.infer_schema(fn, mutates_args)
2026-08-08 17:24:03.184 [Warning] [ComfyUI-0/STDERR] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-08-08 17:24:03.185 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/torch/_library/infer_schema.py", line 42, in infer_schema
2026-08-08 17:24:03.185 [Warning] [ComfyUI-0/STDERR] error_fn(
2026-08-08 17:24:03.185 [Warning] [ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/torch/_library/infer_schema.py", line 21, in error_fn
2026-08-08 17:24:03.185 [Warning] [ComfyUI-0/STDERR] raise ValueError(
2026-08-08 17:24:03.186 [Warning] [ComfyUI-0/STDERR] ValueError: infer_schema(func): Parameter kernel_size has unsupported type list[int]. The valid types are: dict_keys([, typing.Optional[torch.Tensor], typing.Sequence[torch.Tensor], typing.List[torch.Tensor], typing.Sequence[typing.Optional[torch.Tensor]], typing.List[typing.Optional[torch.Tensor]], , typing.Optional[int], typing.Sequence[int], typing.List[int], typing.Optional[typing.Sequence[int]], typing.Optional[typing.List[int]], , typing.Optional[float], typing.Sequence[float], typing.List[float], typing.Optional[typing.Sequence[float]], typing.Optional[typing.List[float]], , typing.Optional[bool], typing.Sequence[bool], typing.List[bool], typing.Optional[typing.Sequence[bool]], typing.Optional[typing.List[bool]], , typing.Optional[str], typing.Union[int, float, bool], typing.Union[int, float, bool, NoneType], typing.Sequence[typing.Union[int, float, bool]], typing.List[typing.Union[int, float, bool]], , typing.Optional[torch.dtype], , typing.Optional[torch.device]]). Got func with signature (q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, kernel_size: list[int], is_causal: list[bool], scale: float | None) -> torch.Tensor)
2026-08-08 17:24:03.708 [Info] Self-Start ComfyUI-0 unexpectedly exited (ExitCode=unknown) (if something failed, change setting LogLevel to Debug to see why!)
2026-08-08 17:24:03.708 [Info] Self-Start ComfyUI-0 had errors before shutdown:
[ComfyUI-0/STDERR] [INFO] Adding extra search path checkpoints /home/user/stable-diffusion-webui/models/Stable-diffusion
[ComfyUI-0/STDERR] [INFO] Adding extra search path vae /home/user/stable-diffusion-webui/models/VAE
[ComfyUI-0/STDERR] [INFO] Adding extra search path loras /home/user/stable-diffusion-webui/models/Lora
[ComfyUI-0/STDERR] [INFO] Adding extra search path loras /home/user/stable-diffusion-webui/models/LyCORIS
[ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/ESRGAN
[ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/RealESRGAN
[ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/SwinIR
[ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/upscale-models
[ComfyUI-0/STDERR] [INFO] Adding extra search path upscale_models /home/user/stable-diffusion-webui/models/upscale_models
[ComfyUI-0/STDERR] [INFO] Adding extra search path embeddings /home/user/stable-diffusion-webui/embeddings
[ComfyUI-0/STDERR] [INFO] Adding extra search path embeddings /home/user/stable-diffusion-webui/models/embeddings
[ComfyUI-0/STDERR] [INFO] Adding extra search path hypernetworks /home/user/stable-diffusion-webui/models/hypernetworks
[ComfyUI-0/STDERR] [INFO] Adding extra search path controlnet /home/user/stable-diffusion-webui/models/ControlNet
[ComfyUI-0/STDERR] [INFO] Adding extra search path model_patches /home/user/stable-diffusion-webui/models/ControlNet
[ComfyUI-0/STDERR] [INFO] Adding extra search path model_patches /home/user/stable-diffusion-webui/models/model_patches
[ComfyUI-0/STDERR] [INFO] Adding extra search path clip /home/user/stable-diffusion-webui/models/clip
[ComfyUI-0/STDERR] [INFO] Adding extra search path clip /home/user/stable-diffusion-webui/models/CLIP
[ComfyUI-0/STDERR] [INFO] Adding extra search path clip_vision /home/user/stable-diffusion-webui/models/clip_vision
[ComfyUI-0/STDERR] [INFO] Adding extra search path unet /home/user/stable-diffusion-webui/models/unet
[ComfyUI-0/STDERR] [INFO] Adding extra search path diffusion_models /home/user/stable-diffusion-webui/models/diffusion_models
[ComfyUI-0/STDERR] [INFO] Adding extra search path gligen /home/user/stable-diffusion-webui/models/gligen
[ComfyUI-0/STDERR] [INFO] Adding extra search path ipadapter /home/user/stable-diffusion-webui/models/ipadapter
[ComfyUI-0/STDERR] [INFO] Adding extra search path yolov8 /home/user/stable-diffusion-webui/models/yolov8
[ComfyUI-0/STDERR] [INFO] Adding extra search path tensorrt /home/user/stable-diffusion-webui/models/tensorrt
[ComfyUI-0/STDERR] [INFO] Adding extra search path clipseg /home/user/stable-diffusion-webui/models/clipseg
[ComfyUI-0/STDERR] [INFO] Adding extra search path style_models /home/user/stable-diffusion-webui/models/style_models
[ComfyUI-0/STDERR] [INFO] Adding extra search path latent_upscale_models /home/user/stable-diffusion-webui/models/latent_upscale_models
[ComfyUI-0/STDERR] [INFO] Adding extra search path custom_nodes /home/user/swarmui/SwarmUI/src/BuiltinExtensions/ComfyUIBackend/DLNodes
[ComfyUI-0/STDERR] [INFO] Adding extra search path custom_nodes /home/user/swarmui/SwarmUI/src/BuiltinExtensions/ComfyUIBackend/ExtraNodes
[ComfyUI-0/STDERR] Traceback (most recent call last):
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/main.py", line 237, in
[ComfyUI-0/STDERR] import comfy.utils
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/comfy/utils.py", line 25, in
[ComfyUI-0/STDERR] import comfy.memory_management
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/comfy/memory_management.py", line 8, in
[ComfyUI-0/STDERR] from comfy.quant_ops import QuantizedTensor
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/comfy/quant_ops.py", line 23, in
[ComfyUI-0/STDERR] import comfy_kitchen as ck
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/comfy_kitchen/**init**.py", line 3, in
[ComfyUI-0/STDERR] from .backends import cuda as _cuda_backend # noqa: F401
[ComfyUI-0/STDERR] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/comfy_kitchen/backends/cuda/**init**.py", line 161, in
[ComfyUI-0/STDERR] from comfy_kitchen.backends.eager import rope as _eager_rope # noqa: E402
[ComfyUI-0/STDERR] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/comfy_kitchen/backends/eager/**init**.py", line 71, in
[ComfyUI-0/STDERR] from .na import na3d
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/comfy_kitchen/backends/eager/na.py", line 163, in
[ComfyUI-0/STDERR] @torch.library.custom_op("comfy_kitchen::na3d", mutates_args=())
[ComfyUI-0/STDERR] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/torch/_library/custom_ops.py", line 119, in inner
[ComfyUI-0/STDERR] schema_str = torch._custom_op.impl.infer_schema(fn, mutates_args)
[ComfyUI-0/STDERR] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/torch/_library/infer_schema.py", line 42, in infer_schema
[ComfyUI-0/STDERR] error_fn(
[ComfyUI-0/STDERR] File "/home/user/swarmui/SwarmUI/dlbackend/ComfyUI/venv/lib/python3.11/site-packages/torch/_library/infer_schema.py", line 21, in error_fn
[ComfyUI-0/STDERR] raise ValueError(
[ComfyUI-0/STDERR] ValueError: infer_schema(func): Parameter kernel_size has unsupported type list[int]. The valid types are: dict_keys([, typing.Optional[torch.Tensor], typing.Sequence[torch.Tensor], typing.List[torch.Tensor], typing.Sequence[typing.Optional[torch.Tensor]], typing.List[typing.Optional[torch.Tensor]], , typing.Optional[int], typing.Sequence[int], typing.List[int], typing.Optional[typing.Sequence[int]], typing.Optional[typing.List[int]], , typing.Optional[float], typing.Sequence[float], typing.List[float], typing.Optional[typing.Sequence[float]], typing.Optional[typing.List[float]], , typing.Optional[bool], typing.Sequence[bool], typing.List[bool], typing.Optional[typing.Sequence[bool]], typing.Optional[typing.List[bool]], , typing.Optional[str], typing.Union[int, float, bool], typing.Union[int, float, bool, NoneType], typing.Sequence[typing.Union[int, float, bool]], typing.List[typing.Union[int, float, bool]], , typing.Optional[torch.dtype], , typing.Optional[torch.device]]). Got func with signature (q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, kernel_size: list[int], is_causal: list[bool], scale: float | None) -> torch.Tensor)
2026-08-08 17:24:03.710 [Debug] Status of ComfyUI-0 after process end is LOADING
2026-08-08 17:24:03.712 [Error] Self-Start ComfyUI-0 on port 7821 failed. AutoRestart ignored as this was an initial launch failure.
2026-08-08 17:24:04.094 [Debug] [Load ComfyUI Self-Starting #0] ComfyUI-0 self-start port 7821 loop ending (failed?)
2026-08-08 17:24:04.249 [Info] Creating new session 'local' for 127.0.0.1
2026-08-08 17:24:04.293 [Debug] User local requested weak refresh within 10 seconds of last refresh, ignoring as redundant.
2026-08-08 17:24:04.293 [Debug] Data refreshed!
2026-08-08 17:24:08.602 [Debug] User local requested check for updates.
2026-08-08 17:24:09.033 [Debug] Git fetch of /home/user/swarmui/SwarmUI says:
2026-08-08 17:24:09.036 [Debug] Git fetch of /home/user/swarmui/SwarmUI/src/Extensions/SwarmUI-FaceTools/ says:
2026-08-08 17:24:09.046 [Debug] Check for updates found 0 updates to SwarmUI core.
2026-08-08 17:24:09.067 [Debug] Check for updates found 3 updates to extension 'FaceToolsExtension'.
2026-08-08 17:24:09.102 [Debug] Git fetch of /home/user/swarmui/SwarmUI/src/Extensions/SwarmUI-PromptBuilderExtension/ says:
2026-08-08 17:24:09.109 [Debug] Check for updates found no updates to extension 'PromptBuilderExtension'.
2026-08-08 17:24:09.167 [Debug] Git fetch of /home/user/swarmui/SwarmUI/dlbackend/ComfyUI says:
2026-08-08 17:24:09.176 [Debug] Check for updates found no updates for ComfyUI install at /home/user/swarmui/SwarmUI/dlbackend/ComfyUI
2026-08-08 17:24:09.749 [Debug] Git fetch of src/BuiltinExtensions/ComfyUIBackend/DLNodes/ComfyUI_IPAdapter_plus says:
2026-08-08 17:24:09.755 [Debug] Git fetch of src/BuiltinExtensions/ComfyUIBackend/DLNodes/ComfyUI-SAI_API says:
2026-08-08 17:24:09.767 [Debug] Check for updates found no updates for ComfyUI node at src/BuiltinExtensions/ComfyUIBackend/DLNodes/ComfyUI_IPAdapter_plus
2026-08-08 17:24:09.767 [Debug] Check for updates found no updates for ComfyUI node at src/BuiltinExtensions/ComfyUIBackend/DLNodes/ComfyUI-SAI_API
```

### Other

Recent ComfyUI versions pull in comfy-kitchen (via requirements / ComfyUI-Manager).

Starting with comfy-kitchen ≥ 0.2.28 the package registers a custom op that uses PEP-585 annotations (list[int], list[bool]).

torch.library.infer_schema only accepts these annotations from PyTorch 2.7.0 onward. On any older torch the import fails hard:
ValueError: infer_schema(func): Parameter kernel_size has unsupported type list[int]
textThis aborts ComfyUI at startup (see log).

Users with legacy hardware might decide to pin their PyTorch version, but will then run into this issue on every update.

Currently, users with older PyTorch can manually uninstall comfy-kitchen, create a wrapper script with the launch shell to prevent reinstall, and manually add try-except blocks in the following python scripts that assume comfy-kitchen is present:
. comfy/quant_ops.py
. comfy/float.py
. comfy/text_encoders/llama.py
. comfy/ldm/modules/attention.py
. comfy/ldm/lightricks/vae/na_diffusion_decoder.py
. comfy/ldm/joyimage/model.py
. any future files that import it

These patches are also lost on every ComfyUI update, requiring tedious manual patching every time.

Suggest making the `comfy_kitchen` dependency optional (for users with PyTorch ≥ 2.7) and guard every import with:

try:
import comfy_kitchen as ck
# etc.
except (ImportError, ValueError):
ck = None
# fall back to pure-PyTorch / older code paths

This would restore functionality for legacy hardware without affecting modern users who can run PyTorch ≥ 2.7.
Users with legacy hardware will not have comfy-kitchen installed, but those cards will not be able to make use of the the FP8 / NVFP4 kernels that comfy-kitchen provides anyway.

Happy to test any proposed patch

Start with dlbackend/ComfyUI/main.py and the self-start launch path, then reproduce the import failure using PyTorch 2.4.1 and a recent comfy-kitchen version. Trace the comfy_kitchen import error and confirm that ComfyUI starts successfully on PyTorch versions below 2.7, including the GTX 1050 environment described.

Written by the indexing model from the issue text.