net.declared_via_drill

What it is ¶

net.declared_via_drill(net, mm) yields the via drill that the project’s own net-class declarations set for a net, held in metres and shown in mm. The net SHOULD be routed at that drill. There is one row per net the project actually constrained. It is the resolved answer, taken after the cascade across the net’s classes has run.

Pair it with board.via_drill(net, mm), the ACTUAL routed value in the same units. A comparison of the two uses no number that the engine invented.

For hardware engineers ¶

A net can sit in several classes at once, and the classes can disagree. KiCad does not pick one class and use it wholesale. It fills each constraint from the highest-priority class that states that particular constraint, and the Default class fills whatever is left over. So a net can take its clearance from one class and its via drill from another, exactly as the tool does when it routes.

This relation is that same resolution, so the number here is the number your layout tool would enforce. Ask it when you want to know what a net was supposed to be, not what it is.

For software engineers ¶

Join THIS, not netclass.via_drill. Membership is 1:many (WS1-050), so joining net.netclass(?net, ?class) to the per-class relation fans out over every class the net belongs to, and a comparison then fires against classes that lost the cascade. So a net can be routed correctly to its winning class’s value and still produce a confident, wrong finding.

Rows are 1:1 with constrained nets. If none of a net’s classes states this quantity, the net yields no row. A rule joining it then selects only nets that the project genuinely constrained, and not net.declared_via_drill(?n, ?_) reads as unconstrained.

Go projector ¶

netDeclaredFacts in stdlib/relations/facts.go. For each net it orders the net’s classes by the project’s priority (ascending, unstated and unknown classes last) and takes the first class that states the field, independently per field. The citation records WHICH class supplied the value (net_settings:<class>), so a finding can say where the limit came from.

Absence is not a pass ¶

Only a KiCad project read populates this, and only when the project declares class definitions. On every other source, a rule comparing declared against actual finds nothing to compare and reports clean. A review cannot tell that from a genuine pass. Such a rule gates on check.CapNetClassDefs, queryable as design.has_netclass_defs (and on the board tier for the actual side), so an absent declaration reads not-applicable.

Datalog ¶

What every constrained net should route at:

net.declared_via_drill(?net, ?mm) => ?net, ?mm

Nets routed smaller than their own project demands:

net.declared_via_drill(?net, ?declared), board.via_drill(?net, ?actual), ?actual < ?declared => ?net, ?actual, ?declared