fix(editor): prevent freeze from extremely large line elements (#11556)

Co-authored-by: dwelle <5153846+dwelle@users.noreply.github.com>

packages/excalidraw/data/restore.ts

@@ -101,7 +101,38 @@ type RestoredAppState = Omit<
   "offsetTop" | "offsetLeft" | "width" | "height"
 >;
 
-const MAX_ARROW_PX = 75_000;
+const MAX_LINEAR_PX = 75_000;
+
+// Last resort fix for extremely large linear elements (lines / arrows), which
+// would otherwise freeze the editor while rendering — e.g. a dotted or dashed
+// stroke spanning a huge distance generates an enormous dash array.
+// https://github.com/excalidraw/excalidraw/issues/11497
+const handleOversizedLinearElements = <T extends ExcalidrawLinearElement>(
+  element: T,
+): T => {
+  if (element.width <= MAX_LINEAR_PX && element.height <= MAX_LINEAR_PX) {
+    return element;
+  }
+
+  const label =
+    element.type === "arrow"
+      ? `${isElbowArrow(element) ? "elbow" : "simple"} arrow`
+      : element.type;
+
+  console.error(
+    `Removing extremely large ${label} ${element.id} (width: ${element.width}, height: ${element.height}, x: ${element.x}, y: ${element.y})`,
+  );
+
+  return {
+    ...element,
+    x: 0,
+    y: 0,
+    width: 100,
+    height: 100,
+    points: [pointFrom<LocalPoint>(0, 0), pointFrom<LocalPoint>(100, 100)],
+    isDeleted: true,
+  };
+};
 
 const restoreLinearElementPoints = (
   points: unknown,
@@ -560,7 +591,7 @@ export const restoreElement = (
           } as ExcalidrawLinearElement));
       }
 
-      return restoreElementWithProperties(element, {
+      const restoredLine = restoreElementWithProperties(element, {
         type: "line",
         startBinding: null,
         endBinding: null,
@@ -578,6 +609,8 @@ export const restoreElement = (
           : {}),
         ...getSizeFromPoints(points),
       });
+
+      return handleOversizedLinearElements(restoredLine);
     case "arrow": {
       const startArrowhead = normalizeArrowhead(element.startArrowhead);
       const endArrowhead =
@@ -644,37 +677,7 @@ export const restoreElement = (
         ),
       };
 
-      // Last resort fix for extremely large arrows
-      if (
-        normalizedRestoredElement.width > MAX_ARROW_PX ||
-        normalizedRestoredElement.height > MAX_ARROW_PX
-      ) {
-        console.error(
-          `Removing extremely large arrow ${
-            normalizedRestoredElement.id
-          } (type: ${
-            isElbowArrow(normalizedRestoredElement) ? "elbow" : "simple"
-          }, width: ${normalizedRestoredElement.width}, height: ${
-            normalizedRestoredElement.height
-          }, x: ${normalizedRestoredElement.x}, y: ${
-            normalizedRestoredElement.y
-          })`,
-        );
-        return {
-          ...normalizedRestoredElement,
-          x: 0,
-          y: 0,
-          width: 100,
-          height: 100,
-          points: [
-            pointFrom<LocalPoint>(0, 0),
-            pointFrom<LocalPoint>(100, 100),
-          ],
-          isDeleted: true,
-        };
-      }
-
-      return normalizedRestoredElement;
+      return handleOversizedLinearElements(normalizedRestoredElement);
     }
 
     // generic elements

packages/excalidraw/tests/data/restore.test.ts

@@ -526,6 +526,53 @@ describe("restoreElements", () => {
     ]);
   });
 
+  it("should mark extremely large linear elements as deleted to avoid freezing", () => {
+    const consoleError = vi
+      .spyOn(console, "error")
+      .mockImplementation(() => {});
+
+    // a degenerate line with astronomical coordinates (see #11497)
+    const hugeLine: any = API.createElement({
+      type: "line",
+      x: 419048829414166,
+      y: 8484,
+    });
+    hugeLine.points = [
+      [0, 0],
+      [-302985021938436, 0],
+      [-838097658820234, 30],
+    ];
+
+    const hugeArrow: any = API.createElement({ type: "arrow" });
+    hugeArrow.points = [
+      [0, 0],
+      [900000, 0],
+    ];
+
+    const normalLine: any = API.createElement({ type: "line" });
+    normalLine.points = [
+      [0, 0],
+      [100, 200],
+    ];
+
+    const [restoredLine, restoredArrow, restoredNormal] =
+      restore.restoreElements([hugeLine, hugeArrow, normalLine], null);
+
+    expect(restoredLine.isDeleted).toBe(true);
+    expect(restoredLine.width).toBe(100);
+    expect(restoredLine.height).toBe(100);
+
+    expect(restoredArrow.isDeleted).toBe(true);
+    expect(restoredArrow.width).toBe(100);
+    expect(restoredArrow.height).toBe(100);
+
+    expect(restoredNormal.isDeleted).toBe(false);
+    expect(restoredNormal.width).toBe(100);
+    expect(restoredNormal.height).toBe(200);
+
+    consoleError.mockRestore();
+  });
+
   it("when the number of points of a line is greater or equal 2", () => {
     const lineElement_0 = API.createElement({
       type: "line",