[QGIS-Developer] GDAL processing algorithms issues due the default output layer extensions weirdly changed

[Andrea Giudiceandrea]

I've recently seen 3 other reports from as many users [1] [2] [3] using 
QGIS 3.36 and QGIS 3.34 about the same issue which completely disrupts 
the functionality of the GDAL processing algorithms.

Maybe the fix could be to just totally avoid to use the "-1" value as 
the default for the "Default output [vector|raster] layer extension" and 
use the value 0 instead. I don't have enough knowledge of the settings 
logic to propose a fix, anyway I think it would be great if the 
underlying root cause of the issue could be fixed ASAP.

Best regards.

[1] https://github.com/qgis/QGIS/issues/56588
[2] 
https://gis.stackexchange.com/questions/478050/raster-to-vector-bunch-of-errors/
[3] https://lists.osgeo.org/pipermail/qgis-user/2024-March/054176.html