sigtools

library4.0.1pypypi✓ verified 24d ago

sigtools is a Python package that enhances introspection capabilities for determining function signatures, especially when decorators modify them. It provides utilities for boosting callable signature introspection, backports keyword-only parameters for older Python versions (though current versions are Python 3+), and tools for combining functions while preserving correct signatures. The current version is 4.0.1, with releases occurring periodically to maintain compatibility and add features.

serialization

pip install sigtools

package ↗homepage ↗

INSTALL

IMPORT

SIG · SIGTOOLS

sigtools

serializationpythonv4.0.1

Install

1.6s avg

Import

93ms

Disk

17MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v4.0.1 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.098s · 18.9MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.6s · import 0.088s · 19MB

17MB installed

● package 17MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

signature

✓ from sigtools import signature

✗ import inspect; inspect.signature(func)

When using `sigtools` decorators or features, `inspect.signature` may not reflect the *effective* signature of the callable. Always use `sigtools.signature` to get the correct signature managed by `sigtools`.

specifiers

✓ from sigtools import specifiers

wrappers

✓ from sigtools import wrappers

modifiers

✓ from sigtools import modifiers

This example demonstrates how to use `sigtools.signature` to introspect a function and how the `@signature` decorator can be used to explicitly set a function's introspectable signature, making `wrapped_func` appear with the same signature as `original_func`.

from sigtools import signature def original_func(a, b): pass @signature(original_func) def wrapped_func(c, d): # This function's signature is now effectively (a, b) due to @signature(original_func) pass print(f"Original signature: {signature(original_func)}") print(f"Wrapped signature: {signature(wrapped_func)}")

Debug

Known issues

breakingSigtools versions 4.0.0 and above officially require Python 3.6 or newer. Older versions offered Python 2 compatibility or backports, but this support has been removed.

fix

Ensure your project runs on Python 3.6 or a more recent version. If Python 2 compatibility is essential, you may need to use an older `sigtools` version (e.g., <2.0) at your own risk, but this is not recommended due to Python 2's end-of-life.

affects: >=4.0.0

gotchaWhen `sigtools` decorators (like `@signature`, `@specifiers.forwards_to`, `@modifiers.kwoargs`) are applied to a callable, the standard `inspect.signature` will often *not* reflect the modified or intended effective signature. Always use `sigtools.signature` for accurate introspection of callables managed by `sigtools`.

fix

Replace `inspect.signature(your_callable)` with `sigtools.signature(your_callable)` to retrieve the signature that `sigtools` has established for the function.

affects: All versions

gotchaCombining functions with `sigtools.wrappers` or managing argument forwarding with `sigtools.specifiers` can introduce complexity in understanding how arguments are mapped or interpreted. Misunderstanding these mechanisms can lead to unexpected `TypeError` or `AttributeError` exceptions.

fix

Carefully review the `sigtools` documentation, particularly sections on `sigtools.wrappers` and 'Picking the appropriate arguments for forwards'. Use `sigtools.signature` frequently during development to verify the resulting signature of combined or modified callables.

affects: All versions

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'sigtools'

The 'sigtools' package has not been installed in the current Python environment.

fix

pip install sigtools

TypeError: 'module' object is not callable

The user attempted to use `sigtools.wraps` directly as a decorator, but `sigtools.wraps` is a module, not a callable decorator itself.

fix

import sigtools.wraps

@sigtools.wraps.wraps
def my_decorator(func):
    # ...
    pass

TypeError: sigtools.spec.signature() argument must be a callable

The `sigtools.spec.signature` function was called with an argument that is not a callable object (e.g., an integer, string, or another non-function object).

fix

import sigtools.spec

def my_function(a, b):
    pass

sig = sigtools.spec.signature(my_function)

TypeError: All passed functions must be callable

One or more of the arguments provided to `sigtools.combine()` was not a callable object.

fix

import sigtools

def func1(a):
    pass
def func2(b):
    pass

combined_func = sigtools.combine(func1, func2)

Upgrade

Version history

4.0.1latest on PyPI · released Oct 13, 2022

Audit

Dependencies

No dependency data recorded yet.

Agent activity

8 hits · last 30 days

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Resources

packagehttps://pypi.org/project/sigtools/ ↗

homepagehttps://sigtools.readthedocs.io/ ↗