fix(studio): undo takes back the edit pending at the key even after a later edit claims

packages/studio/src/hooks/usePersistentEditHistory.test.ts

@@ -116,6 +116,29 @@ it("undoes the edit claimed since the key, not a later edit the server took in f
   expect(readFileSync(join(dir, "card.html"), "utf8")).toBe("Y");
 });
 
+it("undoes the edit pending at the key even when a later edit claims before the step", async () => {
+  const { dir, hook, file, save, readFile } = await studio();
+  const atKey = hook().claims();
+  save("B");
+  await act(() =>
+    hook().recordEdit({
+      label: "Moved Title",
+      files: { "index.html": { before: "A", after: "B" } },
+    }),
+  );
+  writeFileSync(join(dir, "card.html"), "Y");
+  await act(() =>
+    hook().recordEdit({ label: "Added Card", files: { "card.html": { before: "", after: "Y" } } }),
+  );
+
+  const undone = await act(() =>
+    hook().undo({ readFile, serialize: (_, task) => task(), claimedAfter: atKey }),
+  );
+  expect(undone).toMatchObject({ ok: true, label: "Undid: Moved Title" });
+  expect(file()).toBe("A");
+  expect(readFileSync(join(dir, "card.html"), "utf8")).toBe("Y");
+});
+
 it("a drag's edits under one key undo as one step, even before the drag goes idle", async () => {
   const { hook, file, save, readFile } = await studio();
   const writes: Array<[before: string, after: string]> = [

packages/studio/src/hooks/usePersistentEditHistory.ts

@@ -55,7 +55,7 @@ function createOwnHistory() {
   const own = new Map<string, OwnFiles>();
   let next: Record<"undo" | "redo", NextStep | null> | null = null;
   let changes = 0;
-  let claimed = { count: 0, id: "" };
+  const claims: string[] = [];
   const remember = (id: string, files: OwnFiles) => {
     const known = own.get(id) ?? {};
     for (const [path, { before, after }] of Object.entries(files)) {
@@ -76,11 +76,9 @@ function createOwnHistory() {
       if (seen === changes) next = { undo: view.back, redo: view.forward };
     },
     changes: () => changes,
-    claimCount: () => claimed.count,
-    claimedAfter: (count: number) => (claimed.count > count ? claimed.id : null),
-    noteClaim: (id: string) => {
-      claimed = { count: claimed.count + 1, id };
-    },
+    claimCount: () => claims.length,
+    claimedAfter: (count: number) => claims[count] ?? null,
+    noteClaim: (id: string) => claims.push(id),
     stepped: (entry: { id: string; undoes?: string }) => {
       const undone = entry.undoes ? own.get(entry.undoes) : undefined;
       if (!undone) return;