Dynamically determine stacklevel for use with warnings.warn(..., stacklevel=X)

warning-stacklevel.py

import inspect
import sys
from pathlib import Path


def warn_stacklevel() -> int:
    """Dynamically determine stacklevel for warnings based on the call stack"""
    try:
        # Grab the root module from the current module '__name__'
        module_name = __name__.partition(".")[0]
        module_path = Path(sys.modules[module_name].__file__)

        # If the module is a folder we're looking at
        # subdirectories, otherwise we're looking for
        # an exact match.
        module_is_folder = module_path.name == "__init__.py"
        if module_is_folder:
            module_path = module_path.parent

        # Look through frames until we find a file that
        # isn't a part of our module, then return that stacklevel.
        for level, frame in enumerate(inspect.stack()):
            # Garbage collecting frames
            frame_filename = Path(frame.filename)
            del frame

            if (
                # If the module is a folder we look at subdirectory
                module_is_folder
                and module_path not in frame_filename.parents
            ) or (
                # Otherwise we're looking for an exact match.
                not module_is_folder
                and module_path != frame_filename
            ):
                return level

    except KeyError:
        pass
    return 0


# Use like so:
import warnings

warnings.warn("This is a warning!", stacklevel=warn_stacklevel())