The schematic net names are fully unique but if we have multiple pads
that are mapped to a NC pin, they need to have unique net names so that
they do not get connected to each other in the ratsnest. This breaks
the schematic parity check as we have modified the netname for some
pads. To work around this, we first maintain the zero-th net without
suffix and then add an additional check in DRC to ensure that we allow
unconnected nets as long as the share a common prefix with the schematic
netname.
This one for symbol <-> footprint. (Original was for
lib footprint <-> board footprint.)
Also fixes a major bug in DRC where we bail out of parity
checking if DRCE_MISSING_FOOTPRINT is set to ignore (or
overflows).
Fixes https://gitlab.com/kicad/code/kicad/-/issues/16671
Threaded DRC access will write to this string, re-allocating the memory
without any synchronization between threads using the string. Comment
adding this listed performance as a reason for using shared strings.
Measured performance does not seem noticeably different in either case,
even with high-error count boards. If there is a case where the
performance is limiting, we can replace these wxStrings with
std::wstring and utilize fmt
Fixes https://gitlab.com/kicad/code/kicad/issues/9888
Seth Hillbrand
Jan Wichmann
Jeff Young
Marek Roszko