[QGIS-Developer] QGIS Server WFS 1.1.0 response XML - properties with xsi:nil="true"

[pathmapper]

Hi,

for a property with NULL value, QGIS Server WFS 1.1.0 includes this 
property with xsi:nil="true" in the response XML.

I noticed this, because other WFS server software is omitting these 
properties with NULL values.

Having a dataset with lots of features and properties with NULL values, 
the data size of the XML response document increases significantly 
(loading and processing times !) with these xsi:nil="true" properties 
compared to omitting and not including them in the XML response.

After digging a lot trough OGC specs, mailing lists, and gh issues I 
still didn’t find an answer to the questions

a) if QGIS Server is complying to the WFS 1.1.0 spec doing so
and
b) why QGIS Server is doing this?

According to [1] omitting the properties “is by design, as it's a WFS 
specification“. Unfortunately the mentioned link to a thread on an OGC 
mailing list isn‘t working anymore (nabble.com shut down).

Would be great if someone can give an insight.

Cheers,
Bjoern

[1] https://stackoverflow.com/a/25507256