The following testcase fails:

from gi.repository import Gtk, GdkPixbuf, Gdk, GtkSource
import os, sys

languageManager = GtkSource.LanguageManager()
languages = languageManager.get_language_ids()
goLanguage = languageManager.get_language('go')
print (goLanguage.get_style_ids()); # works
chdrLanguage = languageManager.get_language('chdr')
print (chdrLanguage.get_style_ids())  # causes "assertion failed: (arg->v_pointer

The assertion is due to the fact that get_style_ids returns a gchar** array but it may also return NULL when there are no ids. Pygobject does not handle that.

The follwing patches fix the issue and add a testcase that also reproduce the issue. However I am not sure if NULL should be handled as [] like in the patch or if it should be handled ad None.

Do we need a special annotation to say that NULL is a valid value?