cocoindex-io/cocoindex · error · TypeError

Unknown memo_key parameter(s) for {qualified_name(fn)}(): {u

Error message

Unknown memo_key parameter(s) for {qualified_name(fn)}(): {unknown}

What it means

This is a near-duplicate of the _normalize_memo_key ValueError but raised from a later diagnostic path in the same validation, with the unknown names formatted via a single interpolated value. It fires when memo_key references parameters absent from the decorated function's signature.

Source

Thrown at python/cocoindex/_internal/function.py:546

    if memo_key is None:
        return None

    normalized = dict(memo_key)
    if not normalized:
        return None

    sig = inspect.signature(fn)
    param_names = {param.name for param in sig.parameters.values()}
    unknown = sorted(name for name in normalized if name not in param_names)
    if unknown:
        raise ValueError(
            f"Unknown memo_key parameter(s) for {qualified_name(fn)}(): "
            + ", ".join(unknown)
        )

    for name, transform in normalized.items():
        if transform is not None and not callable(transform):
            raise TypeError(
                f"memo_key[{name!r}] for {qualified_name(fn)}() must be a callable or None"
            )

    positional: list[MemoKeyTransform | None | NotSetType] = []
    varargs_override: MemoKeyTransform | None | NotSetType = NOT_SET
    varkw_override: MemoKeyTransform | None | NotSetType = NOT_SET

    for param in sig.parameters.values():
        if param.kind in (
            inspect.Parameter.POSITIONAL_ONLY,
            inspect.Parameter.POSITIONAL_OR_KEYWORD,
        ):
            if param.name in normalized:
                positional.append(normalized[param.name])
            else:
                positional.append(NOT_SET)
        elif param.kind == inspect.Parameter.VAR_POSITIONAL:
            if param.name in normalized:

View on GitHub (pinned to e84aa99b32)

Solutions

1. Fix the memo_key keys to match declared parameters
2. Keep memo_key specs co-located with the function definition to catch drift in review
3. Add a unit test decorating the function at import time so the ValueError surfaces early

Example fix

# before
@coco.fn(memo_key={"old_param": None})
async def f(new_param: str): ...

# after
@coco.fn(memo_key={"new_param": None})
async def f(new_param: str): ...

import inspect
assert set(memo_key) <= set(inspect.signature(fn).parameters), "memo_key names must match fn parameters"

When it happens

Trigger: Same as error 37: @coco.fn(memo_key={...}) containing a name not in fn's parameters, reached via the alternate validation/reporting branch in _normalize_memo_key (called from __init__ and tests).

Common situations: Typos, stale parameter names after refactoring, or reused memo_key dicts across different functions.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Unknown memo_key parameter(s) for {qualified_name(fn)}(): {'
• memo_key transform for *args must return tuple, got {type(va
• memo_key transform for **kwargs must return dict, got {type(
• deps= requires logic_tracking to be enabled; with logic_trac
• coco.use_state() cannot be called inside a memoized function

AI-assisted analysis of cocoindex-io/cocoindex@e84aa99b32 (2026-09-08). Data as JSON: /api/errors/d07f59409839ed4b. Report an issue: GitHub.