Check for vias inside pads

[seveibar]

Summary

• add and export checkViasInPads
• report a PCB placement error when a via center lies inside an SMD or plated-through pad on an overlapping copper layer
• use the pad's true geometry rather than only its bounding box
• include the rule in runAllPlacementChecks / runAllChecks
• skip the rule when pcb_board.is_via_in_pad_allowed is explicitly true

Why

Via-in-pad usually requires an intentional manufacturing process. With the new circuit-json board flag, checks can reject accidental vias in pads while allowing designs that explicitly opt in.

The rule uses backward-compatible feature detection for the board flag so this focused PR does not need to pull in unrelated schema migrations through the repository's pinned development dependency.

Validation

• bun test tests/lib/check-vias-in-pads.test.ts (4 passing)
• bun test (141 passing)
• bunx tsc --noEmit
• bun run build
• bunx @tscircuit/dependency-check
• Biome formatting on all touched files
• git diff --check

[graphite-app]

This file contains 4 test(...) calls (at lines 49, 65, 121, and 143), but the style guide requires that a *.test.ts file may have AT MOST one test(...). After the first test, the remaining tests should be split into separate, numbered files. For example: check-vias-in-pads1.test.ts, check-vias-in-pads2.test.ts, check-vias-in-pads3.test.ts, and check-vias-in-pads4.test.ts.

Suggested change

	test("reports a via whose center is inside an SMD pad", async () => {
	const circuitJson: AnyCircuitElement[] = [makeBoard(), rectPad, viaInRectPad]
	const errors = checkViasInPads(circuitJson)
	expect(errors).toHaveLength(1)
	expect(errors[0]).toMatchObject({
	type: "pcb_placement_error",
	pcb_placement_error_id: "via_in_pad_pcb_via_1_pcb_smtpad_1",
	error_type: "pcb_placement_error",
	})
	expect(errors[0].message).toContain("is inside SMD pad")
	expect(containsCircuitJsonId(errors[0].message)).toBe(false)
	expect(await runAllPlacementChecks(circuitJson)).toContainEqual(errors[0])
	})
	test("uses true pad geometry for circular, polygon, and plated-hole pads", () => {
	const circuitJson: AnyCircuitElement[] = [
	makeBoard(),
	{
	type: "pcb_smtpad",
	pcb_smtpad_id: "pcb_smtpad_circle",
	shape: "circle",
	x: -4,
	y: 0,
	radius: 0.5,
	layer: "top",
	},
	{
	type: "pcb_smtpad",
	pcb_smtpad_id: "pcb_smtpad_polygon",
	shape: "polygon",
	points: [
	{ x: -0.5, y: -0.5 },
	{ x: 0.5, y: -0.5 },
	{ x: 0, y: 0.5 },
	],
	layer: "top",
	},
	{
	type: "pcb_plated_hole",
	pcb_plated_hole_id: "pcb_plated_hole_1",
	shape: "circle",
	x: 4,
	y: 0,
	outer_diameter: 1,
	hole_diameter: 0.5,
	layers: ["top", "bottom"],
	},
	{
	...viaInRectPad,
	pcb_via_id: "pcb_via_circle",
	x: -4.2,
	y: 0,
	},
	{
	...viaInRectPad,
	pcb_via_id: "pcb_via_polygon",
	x: 0,
	y: 0,
	},
	{
	...viaInRectPad,
	pcb_via_id: "pcb_via_plated_hole",
	x: 4,
	y: 0,
	},
	]
	expect(checkViasInPads(circuitJson)).toHaveLength(3)
	})
	test("ignores vias outside pads and vias on non-overlapping layers", () => {
	const circuitJson: AnyCircuitElement[] = [
	makeBoard(),
	rectPad,
	{
	...viaInRectPad,
	pcb_via_id: "pcb_via_outside",
	x: 2,
	y: 2,
	},
	{
	...viaInRectPad,
	pcb_via_id: "pcb_via_inner_layers",
	x: 0,
	y: 0,
	layers: ["inner1", "inner2"],
	},
	]
	expect(checkViasInPads(circuitJson)).toEqual([])
	})
	test("respects the board via-in-pad allowance", () => {
	const allowedCircuit: AnyCircuitElement[] = [
	makeBoard(true),
	rectPad,
	viaInRectPad,
	]
	const disallowedCircuit: AnyCircuitElement[] = [
	makeBoard(false),
	rectPad,
	viaInRectPad,
	]
	expect(checkViasInPads(allowedCircuit)).toEqual([])
	expect(checkViasInPads(disallowedCircuit)).toHaveLength(1)
	})
	test("reports a via whose center is inside an SMD pad", async () => {
	const circuitJson: AnyCircuitElement[] = [makeBoard(), rectPad, viaInRectPad]
	const errors = checkViasInPads(circuitJson)
	expect(errors).toHaveLength(1)
	expect(errors[0]).toMatchObject({
	type: "pcb_placement_error",
	pcb_placement_error_id: "via_in_pad_pcb_via_1_pcb_smtpad_1",
	error_type: "pcb_placement_error",
	})
	expect(errors[0].message).toContain("is inside SMD pad")
	expect(containsCircuitJsonId(errors[0].message)).toBe(false)
	expect(await runAllPlacementChecks(circuitJson)).toContainEqual(errors[0])
	})

Spotted by Graphite (based on custom rule: Custom rule)



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[tscircuitbot]

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PR Rating: ⭐⭐
Impact: Minor

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