What language does this apply to?

Python

Describe the problem you are trying to solve.

Would like to be able to use the Python extension in subinterpreters or after reload.

Because of the assignment at

to the C-static variable, the error is triggered in subinterpreters or when reloading the module. This is because the message class may not be the same in a subinterpreter/reload as it was when the module was first loaded.

Describe the solution you'd like

Options:

1. See PEP 3121. Start using module state instead of C-static state so it can be safely reloaded.
2. Stop checking for module class extension using static state