fix: prevent hop-over and junction overlap

lib/components/primitive-components/Group/Group_doInitialSchematicTraceRender/compute-crossings.ts

@@ -160,6 +160,26 @@ export function computeCrossings(
   const crossLen = opts.crossSegmentLength ?? 0.075
   const tol = opts.tolerance ?? TOL
 
+  // Precompute endpoint orientations for all traces to help choose which
+  // trace receives a crossing when a junction is also present at the
+  // intersection point.
+  const endpointInfo = new Map<
+    string,
+    Array<{ traceIdx: number; orient: "horizontal" | "vertical" }>
+  >()
+  for (let ti = 0; ti < traces.length; ti++) {
+    const trace = traces[ti]
+    for (const e of trace.edges) {
+      const orient = isHorizontalEdge(e) ? "horizontal" : "vertical"
+      for (const p of [e.from, e.to]) {
+        const key = `${p.x.toFixed(6)},${p.y.toFixed(6)}`
+        const arr = endpointInfo.get(key) ?? []
+        arr.push({ traceIdx: ti, orient })
+        endpointInfo.set(key, arr)
+      }
+    }
+  }
+
   // Collect intersections per edge reference
   type EdgeRef = { traceIdx: number; edgeIdx: number }
   const crossingsByEdge = new Map<string, number[]>()
@@ -196,12 +216,25 @@ export function computeCrossings(
           // Crossing is when both are away from endpoints
           if (!nearEndpointA && !nearEndpointB) {
             // Only one of the traces should receive the crossing marker.
-            // Prefer assigning the crossing to the more horizontal edge.
+            // Prefer assigning the crossing to the more horizontal edge, but if
+            // there's a junction at this point choose the edge that doesn't
+            // participate in that junction to avoid overlap.
+
+            const pointKey = `${P.x.toFixed(6)},${P.y.toFixed(6)}`
+            const otherOrients = new Set(
+              (endpointInfo.get(pointKey) ?? [])
+                .filter((info) => info.traceIdx !== ti && info.traceIdx !== tj)
+                .map((info) => info.orient),
+            )
+
             const aIsHorizontal = isHorizontalEdge(eA)
             const bIsHorizontal = isHorizontalEdge(eB)
 
             let assignToA: boolean
-            if (aIsHorizontal !== bIsHorizontal) {
+            if (otherOrients.size === 1 && aIsHorizontal !== bIsHorizontal) {
+              const orient = otherOrients.values().next().value
+              assignToA = orient === "horizontal" ? aIsHorizontal : !aIsHorizontal
+            } else if (aIsHorizontal !== bIsHorizontal) {
               // If exactly one is horizontal, prefer the horizontal one
               assignToA = aIsHorizontal
             } else {

tests/repros/repro51-junction-hop-overlap.test.tsx

@@ -0,0 +1,73 @@
+import { test, expect } from "bun:test"
+import { getTestFixture } from "../fixtures/get-test-fixture"
+
+test("repro51: junction and hop over traces do not overlap", () => {
+  const { circuit } = getTestFixture()
+
+  circuit.add(
+    <board pcbPack>
+      {/* --- 555 timer as a generic 8‑pin chip --- */}
+      <chip
+        name="U1"
+        footprint="soic8"
+        pinLabels={{
+          pin1: "GND",
+          pin2: "TRIG",
+          pin3: "OUT",
+          pin4: "RESET",
+          pin5: "CTRL",
+          pin6: "THRES",
+          pin7: "DISCH",
+          pin8: "VCC",
+        }}
+        schPinArrangement={{
+          leftSide: {
+            direction: "top-to-bottom",
+            pins: ["RESET", "CTRL", "THRES", "TRIG"],
+          },
+          rightSide: {
+            direction: "top-to-bottom",
+            pins: ["VCC", "OUT", "DISCH", "GND"],
+          },
+        }}
+      />
+      {/* VCC -> DISCH */}
+      <resistor name="R2" resistance="10k" footprint="0805" />{" "}
+      {/* DISCH -> node */}
+      <capacitor name="C1" capacitance="10uF" footprint="1206" />{" "}
+      {/* node -> GND */}
+      <capacitor name="C2" capacitance="10nF" footprint="0805" />{" "}
+      {/* CTRL -> GND (stability) */}
+      {/* 3-pin header for power + output */}
+      <pinheader
+        name="J1"
+        pinCount={3}
+        footprint="pinrow3"
+        gender="male"
+        schFacingDirection="left"
+        pinLabels={{ pin1: "VCC", pin2: "OUT", pin3: "GND" }}
+        connections={{ VCC: "net.VCC", OUT: "net.OUT", GND: "net.GND" }}
+      />
+      {/* Power & housekeeping */}
+      <trace from="U1.VCC" to="net.VCC" />
+      <trace from="U1.GND" to="net.GND" />
+      <trace from="U1.RESET" to="net.VCC" />
+      <trace from="U1.CTRL" to="C2.pin1" />
+      <trace from="C2.pin2" to="net.GND" />
+      {/* Astable wiring: tie THRES & TRIG; R1, R2, C1 form RC network */}
+      <trace from="U1.THRES" to="net.NODE" />
+      <trace from="U1.TRIG" to="net.NODE" />
+      <trace from="R2.pin2" to="net.NODE" />
+      <trace from="C1.pin1" to="net.NODE" />
+      <trace from="C1.pin2" to="net.GND" />
+      {/* R1 from VCC to DISCH; R2 from DISCH to node */}
+      <trace from="U1.DISCH" to="R2.pin1" />
+      {/* Output to header */}
+      <trace from="U1.OUT" to="net.OUT" />
+    </board>,
+  )
+
+  circuit.render()
+
+  expect(circuit).toMatchSchematicSnapshot(import.meta.path)
+})