invoke-ai/InvokeAI · error

Empty path segments not allowed in subfolder path

Error message

Empty path segments not allowed in subfolder path

What it means

_validate_subfolder rejects empty path segments: a subfolder like 'a//b' or a trailing slash 'a/' splits into '' parts, which is treated as malformed input rather than silently collapsed. The library requires a clean, canonical relative path.

Source

Thrown at invokeai/app/services/video_files/video_files_disk.py:218

    def validate_path(self, path: Union[str, Path]) -> bool:
        path = path if isinstance(path, Path) else Path(path)
        return path.exists()

    @staticmethod
    def _validate_subfolder(subfolder: str) -> None:
        """Validates a subfolder path to prevent directory traversal."""
        if not subfolder:
            return
        if "\\" in subfolder:
            raise ValueError("Backslashes not allowed in subfolder path")
        if subfolder.startswith("/"):
            raise ValueError("Absolute paths not allowed in subfolder path")
        for part in subfolder.split("/"):
            if part == "..":
                raise ValueError("Parent directory references not allowed in subfolder path")
            if part == "":
                raise ValueError("Empty path segments not allowed in subfolder path")

    def __get_sidecar_path(self, video_name: str, video_subfolder: str = "") -> Path:
        sidecar_name = Path(video_name).stem + ".json"
        if video_subfolder:
            self._validate_subfolder(video_subfolder)
            sidecar_path = self.__sidecars_folder / video_subfolder / sidecar_name
        else:
            sidecar_path = self.__sidecars_folder / sidecar_name
        resolved_base = self.__sidecars_folder.resolve()
        resolved_sidecar_path = sidecar_path.resolve()
        if not resolved_sidecar_path.is_relative_to(resolved_base):
            raise ValueError("Sidecar path outside outputs folder, potential directory traversal detected")
        return resolved_sidecar_path

    def __read_sidecar(self, video_name: str, video_subfolder: str = "") -> Optional[dict]:
        path = self.__get_sidecar_path(video_name, video_subfolder=video_subfolder)
        if not path.exists():
            return None

View on GitHub (pinned to 0b6a024f2f)

Solutions

1. Strip duplicate and trailing slashes: subfolder = '/'.join(p for p in raw.split('/') if p)
2. Normalize input with posixpath.normpath and re-check it is relative and non-empty
3. Fix the code that constructs the subfolder string so it never introduces empty segments

Example fix

// before
subfolder = f"{base}/{name}/"
// after
subfolder = "/".join(p for p in f"{base}/{name}".split("/") if p)

import posixpath
def normalize_subfolder(raw: str) -> str:
    cleaned = "/".join(p for p in raw.split("/") if p not in ("", "."))
    assert ".." not in cleaned.split("/"), "traversal not allowed"
    return cleaned

def is_clean_path(sub: str) -> bool:
    return sub != "" and "//" not in sub and not sub.endswith("/")

try:
    path = service.get_path(video_name, subfolder=raw)
except ValueError as e:
    if "Empty path segments" in str(e):
        path = service.get_path(video_name, subfolder=normalize_subfolder(raw))
    else:
        raise

When it happens

Trigger: Passing subfolder='a//b', 'a/', '/a' (leading slash handled separately but trailing still fails), or '' inside get_path / __get_sidecar_path.

Common situations: String concatenation building subpaths ('base' + '/' + name where name already has a slash), URL path segments pasted into config, trailing-slash forms submitted from clients.

Related errors

• Backslashes not allowed in subfolder path
• Absolute paths not allowed in subfolder path
• Empty path segments not allowed in subfolder path
• No existing parent found for {path}
• Not a valid file or directory: {model_path}

AI-assisted analysis of invoke-ai/InvokeAI@0b6a024f2f (2026-08-29). Data as JSON: /api/errors/29f6e1d60e23c21e. Report an issue: GitHub.