What happens if --front-end-version cannot be fetched, and does --front-end-root get any fallback?

Problem. A pinned frontend fails to download, so what UI do you actually get. Conditions. --front-end-version set to a non-default value and no --front-end-root. Method. FrontendManager.init_frontend wraps init_frontend_unsafe in a broad try/except: on any exception it logs 'Failed to initialize frontend' with the error, logs 'Falling back to the default frontend.' and returns the pip-package frontend path. Server startup does not abort. --front-end-root is different: argparse validates the directory at launch (exists, is a directory, readable) and refuses to start otherwise; when valid, server.py uses it directly and never calls init_frontend, so there is no version check or fallback to the pip package. Failure modes. A typo or offline machine yields the packaged frontend silently apart from a log line, so a pin is not a guarantee; check the log line 'web root'. An empty or wrong directory under --front-end-root gives a broken UI with no fallback (inference). Limitations. Interaction with --offline was not tested. Version and date. commit fb3befd, read 2026-10-24. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Static code reading, not executed. Other routes (e.g. static file handlers) in later server code were not read, so claims about a broken UI for a wrong root are inference. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

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  "citations": [
    {
      "url": "https://raw.githubusercontent.com/comfyanonymous/ComfyUI/fb3befd168731438f88bc96e0920a538e8649878/app/frontend_management.py",
      "note": "init_frontend; cli_args.py --front-end-root; is_valid_directory; PromptServer.__init__; researcher reasoning"
    },
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      "url": "https://raw.githubusercontent.com/comfyanonymous/ComfyUI/fb3befd168731438f88bc96e0920a538e8649878/comfy/cli_args.py",
      "note": "init_frontend; cli_args.py --front-end-root; is_valid_directory; PromptServer.__init__; researcher reasoning"
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      "url": "https://raw.githubusercontent.com/comfyanonymous/ComfyUI/fb3befd168731438f88bc96e0920a538e8649878/server.py",
      "note": "init_frontend; cli_args.py --front-end-root; is_valid_directory; PromptServer.__init__; researcher reasoning"
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