bindings: python: fix Line.request() crashing

On an attempt to call the 'request' method of a Line object, the program
crashes with this exception:

> SystemError: ../Objects/dictobject.c:2606: bad argument to internal function
>
> The above exception was the direct cause of the following exception:
>
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> SystemError: <class 'gpiod.LineBulk'> returned a result with an error set

The problem is that keyword args are NULL (rather than an empty dict) if
they are not present. However, PyDict_Size sets an exception if it gets
NULL.

Fixes: 02a3d0a2ab5e ("bindings: python: fix segfault when calling Line.request()")
Signed-off-by: Jiri Benc <jbenc@upir.cz>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/bindings/python/gpiodmodule.c b/bindings/python/gpiodmodule.c
index b3ae2bfebb8a7d6839afc0295ff1687a24d5786c..fee4c32406fabea4e9d7500c2a8b58096cbb8770 100644 (file)
--- a/bindings/python/gpiodmodule.c
+++ b/bindings/python/gpiodmodule.c
@@ -472,7 +472,7 @@ static PyObject *gpiod_Line_request(gpiod_LineObject *self,
        gpiod_LineBulkObject *bulk_obj;
        int rv;
 
-       if (PyDict_Size(kwds) > 0) {
+       if (kwds && PyDict_Size(kwds) > 0) {
                def_val = PyDict_GetItemString(kwds, "default_val");
                def_vals = PyDict_GetItemString(kwds, "default_vals");
        } else {