Fix arrows with weird bends crashing (#1540)

This PR prevents a crash when you try to curve an arrow that is pointing
a very small distance.

Fixes #1533

### Change Type

- [x] `patch` — Bug Fix

### Test Plan

1. Draw a line.
2. Draw an arrow from one point on the line to another point on the
line.
3. It might look weird or flicker (that's ok - that's a *different*
issue - we can fix it another time).
4. Move the middle handle of the arrow.
5. It should curve the arrow.

---

1. Open this snapshot link:
https://www.tldraw.com/s/v2_c_LtB3kVSYEyWuR-aCCrrUn
2. Copy its contents onto your own tldraw.
3. Click on the frog.
4. Drag the handle that's on the frog's face.
5. It shouldn't crash the app.

- [ ] Unit Tests
- [ ] Webdriver tests

### Release Notes

- Fixed a rare crash that could happen when you try to curve an arrow
with zero distance.

packages/editor/src/lib/app/shapeutils/ArrowShapeUtil/arrow/curved-arrow.ts

@@ -4,6 +4,7 @@ import {
 	getPointOnCircle,
 	intersectCirclePolygon,
 	intersectCirclePolyline,
+	isSafeFloat,
 	lerpAngles,
 	Matrix2d,
 	PI,
@@ -48,6 +49,15 @@ export function getCurvedArrowInfo(editor: Editor, shape: TLArrowShape, extraBen
 
 	const handleArc = getArcInfo(a, b, c)
 
+	if (
+		handleArc.length === 0 ||
+		handleArc.size === 0 ||
+		!isSafeFloat(handleArc.length) ||
+		!isSafeFloat(handleArc.size)
+	) {
+		return getStraightArrowInfo(editor, shape)
+	}
+
 	const arrowPageTransform = editor.getPageTransform(shape)!
 
 	if (startShapeInfo && !startShapeInfo.isExact) {

packages/primitives/api-report.md

@@ -315,6 +315,9 @@ export function intersectPolygonPolygon(polygonA: VecLike[], polygonB: VecLike[]
 // @public
 export function isAngleBetween(a: number, b: number, c: number): boolean;
 
+// @public
+export const isSafeFloat: (n: number) => boolean;
+
 // @public (undocumented)
 export function isSelectionCorner(selection: string): selection is SelectionCorner;
 

packages/primitives/src/index.ts

@@ -73,6 +73,7 @@ export {
 	getSweep,
 	getWidth,
 	isAngleBetween,
+	isSafeFloat,
 	lerpAngles,
 	longAngleDist,
 	perimeterOfEllipse,

packages/primitives/src/lib/utils.ts

@@ -674,3 +674,11 @@ export function toDomPrecision(v: number) {
 export function toFixed(v: number) {
 	return +v.toFixed(2)
 }
+
+/**
+ * Check if a float is safe to use. ie: Not too big or small.
+ * @public
+ */
+export const isSafeFloat = (n: number) => {
+	return Math.abs(n) < Number.MAX_SAFE_INTEGER
+}