Show the error cube when a footprint has no 3D model

src/three-components/FootprinterModel.tsx

@@ -33,6 +33,18 @@ export const FootprinterModel = ({
     if (!footprint) return null
     const { geometries } = getJscadModelForFootprint(footprint, jscadModeling)
 
+    // jscad-electronics answers "I have no body for this" with an empty model
+    // rather than an error, and an empty group renders as nothing at all -- the
+    // component silently vanishes from the board with no way to tell it apart
+    // from a part that was never placed. Throwing puts it in front of the
+    // ThreeErrorBoundary the viewers already wrap every model in, which draws
+    // the red error cube and shows this message on hover.
+    if (geometries.flat(Infinity).length === 0) {
+      throw new Error(
+        `No 3D model for footprint "${footprint}" (jscad-electronics returned no geometry)`,
+      )
+    }
+
     const group = new THREE.Group()
 
     for (const geomInfo of geometries.flat(Infinity) as any[]) {

tests/footprinter-empty-model-errors.test.tsx

@@ -0,0 +1,120 @@
+import { expect, test } from "bun:test"
+import * as jscadModeling from "@jscad/modeling"
+import { getJscadModelForFootprint } from "jscad-electronics/vanilla"
+import { JSDOM } from "jsdom"
+import { act } from "react"
+import { createRoot } from "react-dom/client"
+import * as THREE from "three"
+
+const { FootprinterModel } = await import(
+  "../src/three-components/FootprinterModel"
+)
+const { ThreeErrorBoundary } = await import(
+  "../src/three-components/ThreeErrorBoundary"
+)
+const { ThreeContext } = await import("../src/react-three/ThreeContext")
+const { HoverContext } = await import("../src/react-three/HoverContext")
+
+/** A footprint jscad-electronics has no body for. */
+const FOOTPRINT_WITH_NO_MODEL = "res_p0.8656mm_pw0.5657mm_ph0.54mm"
+
+/**
+ * Half of what makes the viewer-side change necessary is upstream silence, so
+ * it is asserted rather than assumed: if jscad-electronics ever starts throwing
+ * for this, or starts returning a body, this test says so instead of leaving a
+ * guard in place for a condition that no longer occurs.
+ */
+test("jscad-electronics reports a missing body as an empty model, not an error", () => {
+  const { geometries } = getJscadModelForFootprint(
+    FOOTPRINT_WITH_NO_MODEL,
+    jscadModeling as any,
+  )
+
+  expect(geometries.flat(Number.POSITIVE_INFINITY)).toHaveLength(0)
+})
+
+/**
+ * Renders one `FootprinterModel` inside the same error boundary the viewers
+ * wrap every model in, and reports what the boundary caught and what reached
+ * the scene. Measured before unmount, since unmounting detaches the group.
+ */
+const renderInBoundary = async (footprint: string) => {
+  const dom = new JSDOM('<div id="root"></div>')
+  const previousWindow = globalThis.window
+  const previousDocument = globalThis.document
+  Object.assign(globalThis, {
+    window: dom.window,
+    document: dom.window.document,
+    IS_REACT_ACT_ENVIRONMENT: true,
+  })
+
+  let caughtError: Error | undefined
+  const rootObject = new THREE.Object3D()
+  const reactRoot = createRoot(dom.window.document.getElementById("root")!)
+  let objectsInScene = 0
+
+  try {
+    await act(async () => {
+      reactRoot.render(
+        <ThreeContext.Provider value={{ rootObject } as any}>
+          <HoverContext.Provider
+            value={{ addHoverable: () => {}, removeHoverable: () => {} }}
+          >
+            <ThreeErrorBoundary
+              fallback={({ error }) => {
+                caughtError ??= error
+                return null
+              }}
+            >
+              <FootprinterModel
+                footprint={footprint}
+                positionOffset={[0, 0, 0]}
+                rotationOffset={[0, 0, 0]}
+                onHover={() => {}}
+                onUnhover={() => {}}
+                isHovered={false}
+              />
+            </ThreeErrorBoundary>
+          </HoverContext.Provider>
+        </ThreeContext.Provider>,
+      )
+    })
+    objectsInScene = rootObject.children.length
+  } finally {
+    await act(async () => reactRoot.unmount())
+    Object.assign(globalThis, {
+      window: previousWindow,
+      document: previousDocument,
+      IS_REACT_ACT_ENVIRONMENT: false,
+    })
+    dom.window.close()
+  }
+
+  return { caughtError, objectsInScene }
+}
+
+/**
+ * An empty model used to build an empty `THREE.Group`: no geometry, no error,
+ * no cube -- the component simply absent from the board, indistinguishable from
+ * one that was never placed. That is how a board lost 26 of its 36 passives
+ * with nothing to search for.
+ *
+ * Throwing during render is what puts it in front of this boundary, which the
+ * viewers back with `Error3d`: the red cube, with the message on hover.
+ */
+test("a footprint with no body raises to the error boundary that draws the cube", async () => {
+  const { caughtError, objectsInScene } = await renderInBoundary(
+    FOOTPRINT_WITH_NO_MODEL,
+  )
+
+  expect(caughtError?.message).toContain("No 3D model for footprint")
+  expect(caughtError?.message).toContain(FOOTPRINT_WITH_NO_MODEL)
+  expect(objectsInScene).toBe(0)
+})
+
+test("a footprint that does have a body still renders it, and raises nothing", async () => {
+  const { caughtError, objectsInScene } = await renderInBoundary("0603")
+
+  expect(caughtError).toBeUndefined()
+  expect(objectsInScene).toBeGreaterThan(0)
+})