What causes "{func.__name__} got too many positioned arguments." in apache/beam?

Remove the extra positional argument or convert it to a keyword argument that the pandas signature accepts.

apache/beam · error · TypeError

got too many positioned arguments.

Error message

{func.__name__} got too many positioned arguments.

What it means

frame_base's function wrapper adapts Beam dataframe implementations to the pandas API signature (base_arg_names). It enforces that callers pass no more positional arguments than the pandas base method accepts, raising this TypeError to prevent arguments from silently being misassigned.

Solutions

Remove the extra positional argument or convert it to a keyword argument that the pandas signature accepts.
Check the current pandas signature of the method and update the call site.
If calling the Beam-internal function, pass Beam-specific arguments as keywords rather than positionally.

Example fix

// before
df.quantile(0.5, 0, 'linear')
// after
df.quantile(0.5, axis=0, interpolation='linear')

Defensive patterns

Strategy: validation

Validate before calling

import inspect
n_base = len(inspect.signature(pd.DataFrame.quantile).parameters)
assert len(args) <= n_base, 'too many positional arguments'

Type guard

def fits_base_signature(args, base_func) -> bool:
    import inspect
    return len(args) <= len(inspect.signature(base_func).parameters)

Try / catch

try:
    df.quantile(*args)
except TypeError as e:
    if 'too many positioned' in str(e):
        df.quantile(*args[:1], **kwargs)
    else:
        raise

Prevention

Call methods by keyword arguments to make arity errors impossible.
Re-check positional args after pandas major-version upgrades.
Avoid calling Beam's internal wrapped functions directly; use the public dataframe API.

When it happens

Trigger: Calling a dataframe method with excess positional args, e.g. df.quantile(0.5, 0, 'linear') passing more positionals than the pandas signature, or a Beam-internal shim invoking a wrapped function with stale extra positional arguments.

Common situations: Code written against an older pandas signature where extra positional args were tolerated; pandas 2.x changes that removed positional parameters; typos adding an extra argument; calling the Beam wrapper directly instead of through the public method.

Understand the failure class

Background: "must be a positive integer", "cannot be empty", "invalid argument": how invalid-argument errors work across open-source libraries — this error's family across 33 libraries.

Related errors

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/2a31b89605d5efe8. Report an issue: GitHub.

Appendix: source

Thrown at sdks/python/apache_beam/dataframe/frame_base.py:517

    # We would need to add position only arguments if they ever become a thing
    # in Pandas (as of 2.1 currently they aren't).
    base_arg_spec = getfullargspec(unwrap(getattr(base_type, func.__name__)))
    base_arg_names = base_arg_spec.args
    # Some arguments are keyword only and we still want to check against those.
    all_possible_base_arg_names = base_arg_names + base_arg_spec.kwonlyargs
    beam_arg_names = getfullargspec(func).args

    if not_found := (set(beam_arg_names) - set(all_possible_base_arg_names) -
                     set(removed_arg_names)):
      raise TypeError(
          f"Beam definition of {func.__name__} has arguments that are not found"
          f" in the base version of the function: {not_found}")

    @functools.wraps(func)
    def wrapper(*args, **kwargs):
      if len(args) > len(base_arg_names):
        raise TypeError(f"{func.__name__} got too many positioned arguments.")

      for name, value in zip(base_arg_names, args):
        if name in kwargs:
          raise TypeError(
              "%s() got multiple values for argument '%s'" %
              (func.__name__, name))
        kwargs[name] = value
      # Still have to populate these for the Beam function signature.
      if removed_args:
        for name in removed_args:
          if name not in kwargs:
            kwargs[name] = None
      return func(**kwargs)

    return wrapper

  return wrap

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