cursed-snakes/namespace-inject.py

import ast
import inspect
from textwrap import dedent
from typing import Callable

#################
# MAGIC SECTION #
#################


class Shoehorn:
    local_fns: tuple[Callable, ...]

    def __init__(self, *local_fn: Callable) -> None:
        self.local_fns = local_fn

    @staticmethod
    def _get_func_def(object: Callable) -> tuple[ast.FunctionDef, ast.Module]:
        object_ast = ast.parse(dedent(inspect.getsource(object)))
        return next(
            x for x in ast.walk(object_ast)
            if isinstance(x, ast.FunctionDef) and x.name == object.__name__
        ), object_ast

    def __call__(self, fn: Callable) -> Callable:
        fn_func_def, fn_ast = self._get_func_def(fn)

        fn_func_def.body = [
            self._get_func_def(lfn)[0]
            for lfn in self.local_fns
        ] + fn_func_def.body

        fn_func_def.decorator_list = [
            decorator
            for decorator in fn_func_def.decorator_list
            if not (
                isinstance(decorator, ast.Call)
                and isinstance(decorator.func, ast.Name)
                and decorator.func.id == Shoehorn.__name__
            )
        ]

        if (fn_sourcefile := inspect.getsourcefile(fn)) is None:
            fn_sourcefile = "<string>"

        exec(
            compile(fn_ast, fn_sourcefile, "exec"),
            fn_globals := {},
        )
        return fn_globals[fn.__name__]

##################
# NORMAL SECTION #
##################


def foo():
    raise NotImplementedError()


def func1(pstr: str) -> None:
    def foo() -> None:
        print(f"{pstr = }")

    foo()


def func2(pstr: str) -> None:
    foo()


def foo_local() -> None:
    print(f"{pstr = }")  # type:ignore # noqa: F821


@Shoehorn(foo_local)
def func3(pstr: str) -> None:
    foo_local()


def func_info(f: Callable) -> None:
    try:
        print(f"{f.__name__} = {f}, {f.__code__.co_varnames = }")
        f("bar")
        f("baz")
    except Exception:
        print(f"Function {f.__name__} is broken.")


if __name__ == "__main__":
    func_info(func1)
    func_info(func2)
    func_info(func3)