Modulemd.ModuleStream.read_string does not accept None for optional arguments

[mprahl]

Modulemd.ModuleStream.read_string has two optional arguments, module_name and module_stream. When interfacing with them in Python, None values are not allowed. Empty strings do work however. Here is the reproducer:

import requests
import gi
gi.require_version("Modulemd", "2.0")
from gi.repository import Modulemd

mmd_str = requests.get(
    'https://pagure.io/fm-orchestrator/raw/master/f/tests/staged_data/platform.yaml').text
Modulemd.ModuleStream.read_string(mmd_str, None, None)

This causes the following traceback:

Traceback (most recent call last):
  File "reproducer.py", line 8, in <module>
    Modulemd.ModuleStream.read_string(mmd_str, None, None)
TypeError: Argument 1 does not allow None as a value

[sgallagher]

The problem here is that you are actually missing the strict argument, which is non-nullable. You probably want to do Modulemd.ModuleStream.read_string(mmd_str, False, None, None) here. (Modulemd.ModuleStream.read_string(mmd_str, False) will also work.

[sgallagher]

Actually, for MBS we probably want to have True there. We want False for DNF to be more tolerant, but on the packager side I think it makes sense to reject unknown values.

[mprahl]

Thanks @sgallagher. I fixed the documentation example in #276.