Comment 4 for bug 1774967

A named net is certainly the "gold standard".

Barring that, we should keep the zone attached to whatever it was attached to. If you update with match-by-reference, then the auto-generated-net-names (which encode reference+pad) are the "silver standard". Today we handle this only when the zone's net-name no longer has any pads. We should probably do it any time the zone's net-name is auto-generated.

However, if you update with match-by-timestamp, then timestamp+pad is the "silver standard". We don't handle this at all today (either when the zone's net-name has no pads or when it's auto-generated).