first_common_ancestor

pythonic_fp.gadgets.first_common_ancestor(cls1: type, cls2: type) → type

Find the least upper bound in the inheritance graph of two classes.

Warning

This function can fail with a TypeError. Some error messages seen are

  • multiple bases have instance lay-out conflict

  • type ‘bool’ is not an acceptable base type

This happens frequently when the function is given Python builtin types or in multiple inheritance situations.

Parameters:

  • cls1 – A class in the inheritance hierarchy.

  • cls2 – A class in the inheritance hierarchy.

Returns:

First common ancestor based on getmro order.

Raises:

TypeError – Raised when no common ancestor or not caught when raised by inspect.getmro.