Fix zero length copper segments

lib/pcb/stages/AddTracesStage.ts

@@ -10,6 +10,11 @@ import { applyToPoint } from "transformation-matrix"
 import { generateDeterministicUuid } from "./utils/generateDeterministicUuid"
 import { getKicadLayer } from "../utils/layerMapping"
 
+const pointsAreEqual = (
+  a?: { x: number; y: number },
+  b?: { x: number; y: number },
+) => !!a && !!b && a.x === b.x && a.y === b.y
+
 /**
  * Adds traces (segments/tracks) to the PCB from circuit JSON
  */
@@ -63,6 +68,16 @@ export class AddTracesStage extends ConverterStage<CircuitJson, KicadPcb> {
         y: endPoint.y,
       })
 
+      if (pointsAreEqual(transformedStart, transformedEnd)) {
+        if (startPoint.layer) {
+          lastKnownLayer = startPoint.layer
+        }
+        if (endPoint.layer) {
+          lastKnownLayer = endPoint.layer
+        }
+        continue
+      }
+
       let netInfo: PcbNetInfo | undefined
       if (pcbNetMap) {
         let connectivityKey: string | undefined =

tests/pcb/repros/repro17-zero-length-trace-segment.test.ts

@@ -0,0 +1,52 @@
+import { expect, test } from "bun:test"
+import type { CircuitJson } from "circuit-json"
+import { CircuitJsonToKicadPcbConverter } from "lib/pcb/CircuitJsonToKicadPcbConverter"
+
+test("duplicate adjacent trace points should not create a zero-length segment", () => {
+  const circuitJson: CircuitJson = [
+    {
+      type: "pcb_board",
+      pcb_board_id: "pcb_board_0",
+      center: { x: 0, y: 0 },
+      thickness: 1.6,
+      num_layers: 2,
+      width: 20,
+      height: 10,
+      material: "fr4",
+    },
+    {
+      type: "source_net",
+      source_net_id: "source_net_1",
+      name: "GND",
+      member_source_group_ids: [],
+      subcircuit_connectivity_map_key: "net.GND",
+    },
+    {
+      type: "source_trace",
+      source_trace_id: "source_trace_1",
+      connected_source_port_ids: [],
+      connected_source_net_ids: ["source_net_1"],
+      subcircuit_connectivity_map_key: "net.GND",
+    },
+    {
+      type: "pcb_trace",
+      pcb_trace_id: "pcb_trace_1",
+      source_trace_id: "source_trace_1",
+      route: [
+        { route_type: "wire", x: 0, y: 0, width: 0.15, layer: "top" },
+        { route_type: "wire", x: 0, y: 0, width: 0.15, layer: "top" },
+        { route_type: "wire", x: 2, y: 0, width: 0.15, layer: "top" },
+      ],
+    },
+  ]
+
+  const converter = new CircuitJsonToKicadPcbConverter(circuitJson)
+  converter.runUntilFinished()
+
+  const output = converter.getOutputString()
+  const segments = output.match(/\(segment[\s\S]*?\(uuid [^)]+\)\n  \)/g) || []
+
+  expect(segments.length).toBe(1)
+  expect(output).not.toContain("(start 100 100)\n    (end 100 100)")
+  expect(output).toContain("(start 100 100)\n    (end 102 100)")
+})