chore: harden local schema hints and tests

excalidraw-app/App.tsx

@@ -54,6 +54,7 @@ import {
   restoreElements,
 } from "@excalidraw/excalidraw/data/restore";
 import {
+  hasElementSchemaVersion,
   migrateSceneElements,
   SCHEMA_VERSIONS,
 } from "@excalidraw/excalidraw/data/schema";
@@ -231,6 +232,17 @@ const initializeScene = async (opts: {
   const externalUrlMatch = window.location.hash.match(/^#url=(.*)$/);
 
   const localDataState = importFromLocalStorage();
+  const localStorageSchemaVersionSource = hasElementSchemaVersion(
+    localDataState?.elements,
+  )
+    ? {
+        payloadSchemaVersion: undefined,
+        fallbackVersion: SCHEMA_VERSIONS.initial,
+      }
+    : {
+        payloadSchemaVersion: localDataState?.schemaVersion,
+        fallbackVersion: SCHEMA_VERSIONS.initial,
+      };
 
   let scene: Omit<
     RestoredDataState,
@@ -243,10 +255,7 @@ const initializeScene = async (opts: {
     elements: restoreElements(
       migrateSceneElements(
         localDataState?.elements,
-        {
-          payloadSchemaVersion: localDataState?.schemaVersion,
-          fallbackVersion: SCHEMA_VERSIONS.initial,
-        },
+        localStorageSchemaVersionSource,
       ),
       null,
       {
@@ -573,12 +582,20 @@ const ExcalidrawWrapper = () => {
         if (isBrowserStorageStateNewer(STORAGE_KEYS.VERSION_DATA_STATE)) {
           const localDataState = importFromLocalStorage();
           const username = importUsernameFromLocalStorage();
+          const localStorageSchemaVersionSource = hasElementSchemaVersion(
+            localDataState?.elements,
+          )
+            ? {
+                payloadSchemaVersion: undefined,
+                fallbackVersion: SCHEMA_VERSIONS.initial,
+              }
+            : {
+                payloadSchemaVersion: localDataState?.schemaVersion,
+                fallbackVersion: SCHEMA_VERSIONS.initial,
+              };
           const migratedElements = migrateSceneElements(
             localDataState?.elements,
-            {
-              payloadSchemaVersion: localDataState?.schemaVersion,
-              fallbackVersion: SCHEMA_VERSIONS.initial,
-            },
+            localStorageSchemaVersionSource,
           );
           setLangCode(getPreferredLanguage());
           excalidrawAPI.updateScene({

excalidraw-app/data/LocalData.ts

@@ -87,9 +87,14 @@ const saveDataStateToLocalStorage = (
       _appState.openSidebar = null;
     }
 
+    const persistedElements = getNonDeletedElements(elements).map((element) => ({
+      ...element,
+      schemaVersion: SCHEMA_VERSIONS.latest,
+    }));
+
     localStorage.setItem(
       STORAGE_KEYS.LOCAL_STORAGE_ELEMENTS,
-      JSON.stringify(getNonDeletedElements(elements)),
+      JSON.stringify(persistedElements),
     );
     localStorage.setItem(
       STORAGE_KEYS.LOCAL_STORAGE_APP_STATE,

packages/excalidraw/data/schema.test.ts

@@ -3,6 +3,7 @@ import { DEFAULT_ELEMENT_PROPS } from "@excalidraw/common";
 import { API } from "../tests/helpers/api";
 import {
   ALL_SCOPES,
+  hasElementSchemaVersion,
   type SchemaMigration,
   migrateAPIElements,
   migrateClipboardElements,
@@ -179,6 +180,34 @@ describe("schema migration", () => {
     expect(migrated[0].backgroundColor).toBe("#ff0000");
   });
 
+  it("should migrate mixed-hint elements individually when payload schema is missing", () => {
+    const legacyFrame = API.createElement({
+      type: "frame",
+      backgroundColor: "#ff0000",
+    });
+    const modernFrame = API.createElement({
+      type: "frame",
+      backgroundColor: "#00ff00",
+    });
+    const modernFrameWithHint = {
+      ...modernFrame,
+      schemaVersion: SCHEMA_VERSIONS.latest,
+    } as typeof modernFrame & { schemaVersion: number };
+
+    const migrated = migrateSceneElements(
+      [legacyFrame, modernFrameWithHint],
+      {
+        payloadSchemaVersion: undefined,
+        fallbackVersion: SCHEMA_VERSIONS.initial,
+      },
+    )!;
+
+    expect(migrated[0].backgroundColor).toBe(
+      DEFAULT_ELEMENT_PROPS.backgroundColor,
+    );
+    expect(migrated[1].backgroundColor).toBe("#00ff00");
+  });
+
   it("should prefer payload schema over per-element schema", () => {
     const frame = API.createElement({
       type: "frame",
@@ -198,4 +227,15 @@ describe("schema migration", () => {
       DEFAULT_ELEMENT_PROPS.backgroundColor,
     );
   });
+
+  it("should detect schema hints on elements", () => {
+    const frame = API.createElement({ type: "frame" });
+    const withHint = {
+      ...frame,
+      schemaVersion: SCHEMA_VERSIONS.latest,
+    } as typeof frame & { schemaVersion: number };
+
+    expect(hasElementSchemaVersion([frame])).toBe(false);
+    expect(hasElementSchemaVersion([withHint])).toBe(true);
+  });
 });

packages/excalidraw/data/schema.ts

@@ -85,6 +85,15 @@ const isValidSchemaVersion = (
   );
 };
 
+export const hasElementSchemaVersion = (
+  elements: readonly ExcalidrawElement[] | null | undefined,
+) =>
+  !!elements?.some((element) =>
+    isValidSchemaVersion(
+      (element as ExcalidrawElement & { schemaVersion?: number }).schemaVersion,
+    ),
+  );
+
 export const validateSchemaMigrations = (
   migrations: readonly SchemaMigration[],
 ) => {