Not sure really what the effect of this is (if any) opening bug here for a queued up master fix that (may) need to be backported.

lib/ldb/pyldb.c

has

static PyObject *py_ldb_control_set_critical(PyLdbControlObject *self, PyObject *value, void *closure)

this function should match 'setter' func signature

		.name = discard_const_p(char, "critical"),
		.get  = (getter)py_ldb_control_get_critical,
		.set  = (setter)py_ldb_control_set_critical, <<<======

so return type is incorrect.

from https://docs.python.org/3/c-api/structures.html

"set functions take two PyObject* parameters (the instance and the value to be set) and a function pointer (the associated closure):

typedef int (*setter)(PyObject *, PyObject *, void *);

In case the attribute should be deleted the second parameter is NULL. Should return 0 on success or -1 with a set exception on failure."

so although we don't ever return -1 we also never return 0.