google/python-fire · error · OSError

Fire was passed a filename which could not be found.

Error message

Fire was passed a filename which could not be found.

What it means

When the argument to fire.import_module contains a path separator but does not exist on disk, fire concludes it was intended as a filename and raises OSError('Fire was passed a filename which could not be found.') rather than trying it as a module name. This distinguishes 'path-like but missing' from the dotted-module case.

Source

Thrown at fire/__main__.py:107

    IOError: if the file or module can not be found or imported.

  Returns:
    Tuple[ModuleType, str]: returns the imported module and the module name,
      usually extracted from the path itself.
  """

  if os.path.exists(module_or_filename):
    # importlib.util.spec_from_file_location requires .py
    if not module_or_filename.endswith('.py'):
      try:  # try as module instead
        return import_from_module_name(module_or_filename)
      except ImportError:
        raise ValueError('Fire can only be called on .py files.')

    return import_from_file_path(module_or_filename)

  if os.path.sep in module_or_filename:  # Use / to detect if it was a filename.
    raise OSError('Fire was passed a filename which could not be found.')

  return import_from_module_name(module_or_filename)  # Assume it's a module.


def main(args):
  """Entrypoint for fire when invoked as a module with python -m fire."""

  if len(args) < 2:
    print(cli_string)
    sys.exit(1)

  module_or_filename = args[1]
  module, module_name = import_module(module_or_filename)

  fire.Fire(module, name=module_name, command=args[2:])


if __name__ == '__main__':

View on GitHub (pinned to 716bbc23d7)

Solutions

1. Check the path exists: `ls dir/subdir/mod.py`.
2. Run the command from the correct working directory, or use an absolute path.
3. If you meant a module, use dots not slashes: `python -m fire pkg.mod`.

Example fix

// before
python -m fire src/modle.py serve   # typo
// after
python -m fire src/model.py serve

import os
arg = 'src/model.py'
if os.path.sep in arg and not os.path.exists(arg):
    raise SystemExit(f'File not found: {os.path.abspath(arg)}')

def is_existing_pathlike_target(arg: str) -> bool:
    return os.path.sep not in arg or os.path.exists(arg)

try:
    module, name = fire_import.import_module(arg)
except OSError as e:
    print(f'{e} — check cwd and spelling of {arg}'); sys.exit(2)

When it happens

Trigger: python -m fire dir/subdir/mod (or any string containing /) where dir/subdir/mod does not exist relative to the cwd — a typo in the directory, a moved file, or running from the wrong directory.

Common situations: Running the CLI from a different cwd than the project root (CI, containers, cron); refactoring that renamed or moved files without updating the command; Windows/Unix path separator mixups.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

• Given file path does not exist.
• Unable to load module from specified path.
• Fire can only be called on .py files.
• FindExecutableOnPath({0},...) failed because first argument
• The command argument must be a string or a sequence of argum

AI-assisted analysis of google/python-fire@716bbc23d7 (2026-08-28). Data as JSON: /api/errors/b9373f0264dd47d4. Report an issue: GitHub.