__dcigettext() contains:

  domainname_len = strlen (domainname);
  xdomainname = (char *) alloca (strlen (categoryname)
				 + domainname_len + 5);

It tries to allocate a buffer on stack, and for domain name causes stack overflow.

There is no portable way to restore after stack overflow or to check it ahead. We can add arbitrary limit for the length of domain name, but it does not guarantee anything. It is just yet one way to crash Python from Python code.