fix: don't create traces for net-label-only connections

lib/solvers/LongDistancePairSolver/LongDistancePairSolver.ts

@@ -56,7 +56,8 @@ export class LongDistancePairSolver extends BaseSolver {
       primaryConnectedPinIds.add(pair.pins[1].pinId)
     }
 
-    const { netConnMap } = getConnectivityMapsFromInputProblem(inputProblem)
+    const { directConnMap, netConnMap } =
+      getConnectivityMapsFromInputProblem(inputProblem)
     this.netConnMap = netConnMap
     const pinMap = new Map<PinId, InputPin & { chipId: string }>()
     for (const chip of inputProblem.chips) {
@@ -72,8 +73,10 @@ export class LongDistancePairSolver extends BaseSolver {
     > = []
     const addedPairKeys = new Set<string>()
 
-    for (const netId of Object.keys(netConnMap.netMap)) {
-      const allPinIdsInNet = netConnMap.getIdsConnectedToNet(netId)
+    // Use directConnMap for candidate pair generation so that net-label-only
+    // connections don't produce long-distance traces.
+    for (const netId of Object.keys(directConnMap.netMap)) {
+      const allPinIdsInNet = directConnMap.getIdsConnectedToNet(netId)
       if (allPinIdsInNet.length < 2) continue
 
       const unconnectedPinIds = allPinIdsInNet.filter(

lib/solvers/MspConnectionPairSolver/MspConnectionPairSolver.ts

@@ -74,7 +74,9 @@ export class MspConnectionPairSolver extends BaseSolver {
       }
     }
 
-    this.queuedDcNetIds = Object.keys(netConnMap.netMap)
+    // Only queue nets from the direct-connection map.  Net-label-only nets
+    // (netConnections) should produce net labels, not MSP pairs / traces.
+    this.queuedDcNetIds = Object.keys(directConnMap.netMap)
   }
 
   override getConstructorParams(): ConstructorParameters<
@@ -93,7 +95,7 @@ export class MspConnectionPairSolver extends BaseSolver {
 
     const dcNetId = this.queuedDcNetIds.shift()!
 
-    const allIds = this.globalConnMap.getIdsConnectedToNet(dcNetId) as string[]
+    const allIds = this.dcConnMap.getIdsConnectedToNet(dcNetId) as string[]
     const directlyConnectedPins = allIds.filter((id) => !!this.pinMap[id])
 
     if (directlyConnectedPins.length <= 1) {

lib/solvers/MspConnectionPairSolver/getConnectivityMapFromInputProblem.ts

@@ -14,7 +14,14 @@ export const getConnectivityMapsFromInputProblem = (
     ])
   }
 
-  const netConnMap = new ConnectivityMap(directConnMap.netMap)
+  // Deep-clone the netMap so that netConnMap mutations (adding net-label
+  // connections) don't pollute directConnMap.  Without this, net-label-only
+  // connections leak into directConnMap and cause spurious MSP pairs / traces.
+  const clonedNetMap: Record<string, string[]> = {}
+  for (const [key, ids] of Object.entries(directConnMap.netMap)) {
+    clonedNetMap[key] = [...ids]
+  }
+  const netConnMap = new ConnectivityMap(clonedNetMap)
 
   for (const netConn of inputProblem.netConnections) {
     netConnMap.addConnections([[netConn.netId, ...netConn.pinIds]])