stubgen-pyx 0.1.3

Generates `.pyi` files from Cython modules in a given package directory.

stubgen-pyx

Automatic stub file generation for Cython extensions.

Installation

pip install stubgen-pyx

Usage

Generate stubs from the command line:

stubgen-pyx /path/to/package

Or use the Python API:

import stubgen_pyx
stubgen_pyx.stubgen("/path/to/package")

Overview

Cython is a widely-used extension language for Python, but type information for Cython modules is often unavailable to static analysis tools. This package generates .pyi stub files that expose type hints and signatures for Cython code, enabling better IDE support and type checking.

Why not use mypy's stubgen?

While mypy's stubgen can generate stubs for compiled extension modules through runtime introspection, it cannot access Cython-specific metadata embedded in the compiled modules. This results in incomplete or inaccurate type information.

stubgen-pyx is designed specifically for Cython and leverages embedded metadata to produce more accurate and complete stub files.

Example

A Cython module like this:

cdef class TestClass:
    """
    This is a class for testing stub file generation.
    """
    a: int

    def __init__(self):
        """
        A docstring for __init__
        """
        self.a = 1

    cpdef b(self):
        """
        A docstring for b
        """
        return self.a

    def c(self):
        """
        A docstring for c
        """
        return self.a

    cdef d(self):
        """
        A docstring for d (this should be ignored)
        """
        return self.a

Generates the following stub file:

class TestClass:
    """
    This is a class for testing stub file generation.
    """
    def __init__(self) -> None:
        """
        A docstring for __init__
        """
        ...

    def b(self):
        """
        A docstring for b
        """
        ...

    def c(self):
        """
        A docstring for c
        """
        ...

Note that cdef methods (like d) are not included since they're not accessible from Python, and public attributes and cpdef methods are properly exposed.

Limitations

Import resolution for cimported types: When types from cimport-ed modules appear in function signatures or class definitions, their imports are not automatically included in the generated stub file.

Workaround: Define a __cimport_types__ list or tuple at the module level containing the types you want exposed:

__cimport_types__ = [SomeType, AnotherType]

These types will then be properly imported in the generated stub file.