[libgpiod] Bug in python binding when requesting output?

[Pedro Botella <pbotella@xxxxxxxxx>]

Hi,

I'm experiencing what I think is a bug in the python bindings for libgpiod.
I believe a line.request with type gpiod.LINE_REQ_DIR_OUT always
results in that line being set to '0'.
To reproduce:
1. request a line with type gpiod.LINE_REQ_DIR_OUT
2. set the line to '1'
3. release the line
4. request the same line with type gpiod.LINE_REQ_DIR_OUT
5. get the value, it should now be '0'

I think the issue is in "gpiod_LineBulk_request" in
https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/bindings/python/gpiodmodule.c
There a call to "gpiod_line_request_bulk" with default_vals being
passed as a pointer. Later on in the code, this parameter is checked
for NULL, if it is not NULL then the values in the array are used as
default_vals.
I believe that a NULL pointer should be passed instead if no
default_vals have been requested when doing a Line.request from
Python.

BR
Pedro