When a spin box is showing a NULL value, we DON'T do the default step
behavior, as that would add one step to the NULL value, which is usually
a very large negative value... so the user will get a very large negative number!
Instead, treat the initial value as 0 instead, and then perform the step.
The original workaround was only supposed to apply to QList/
QVector of QVariantMaps. By replacing them all in sip we
break mapping of signals defined in c++ which are emitted
by Python code.
Fixes exceptions after running processing algorithms in Qt6
builds.
And make sipify handle this nicely. This means that all our non-flag
style enums correctly map across to IntFlag python enums on Qt 6,
fixing issues with negative enum values for these and providing
a better match for the original c++ enum.
