migrate: add migration off .index files

folders.ts

···
-import { join } from "@std/path";
 import { moveFile } from "./utils.ts";
 import { Hsh } from "./hsh.ts";
 import { NotebookPath } from "./notebook.ts";
 
 export async function addFolder(path: NotebookPath, hsh: Hsh) {
   Deno.mkdirSync(path.getAbsolutePath(), { recursive: true });
-  Deno.writeTextFileSync(join(path.getAbsolutePath(), ".index"), "");
   await hsh.emitNotebookChanged?.(
     path.notebook,
     `[hsh]: Add folder ${path}`,
···
       throw new Error(`Folder ${path} is not empty`);
     }
   }
-  Deno.removeSync(path.withEntry(".index").getAbsolutePath());
   Deno.removeSync(path.getAbsolutePath(), { recursive: force });
   await hsh.emitNotebookChanged?.(
     path.notebook,

hsh.ts

···
   async initNotebook(name: string): Promise<Notebook> {
     const root = join(this.config.root, "notebooks", name);
     await initRepo(root);
-    Deno.writeTextFileSync(join(root, ".index"), "");
-    Deno.writeTextFileSync(join(root, ".hsh"), "version: 1\n");
+    Deno.writeTextFileSync(join(root, ".hsh"), "version: 2\n");
     await this.emitNotebookChanged?.(
       new Notebook(name),
       "[hsh]: Create notebook",

migrate.ts

···
-import { existsSync, walkSync } from "@std/fs";
+import { walk, walkSync } from "@std/fs";
 import { decodeTime, ulid } from "@std/ulid";
 
 import { moveFile } from "./utils.ts";
···
 
 const migrations = [
   adoptUlids,
+  removeIndexFiles,
 ];
 
 export async function migrate(notebook: Notebook) {
   for (const migration of migrations) {
     await migration(notebook);
   }
+  Deno.writeTextFileSync(join(notebook.root, ".hsh"), "version: 2\n");
 }
 
 function walkNotebook(path: string) {
···
   });
 }
 
-async function adoptUlids(notebook: Notebook) {
+async function adoptUlids(notebook: Notebook): Promise<void> {
   const root = notebook.root;
   for (const entry of walkNotebook(root)) {
     if (entry.name.startsWith(".")) continue;
···
     moveFile(entry.path, newpath);
     console.log(`renaming ${entry.path} => ${newpath}`);
   }
-  if (!existsSync(join(root, ".hsh"))) {
-    Deno.writeTextFileSync(join(root, ".hsh"), "version: 1\n");
+  commit(notebook, "migrated all markdown entries to ULIDs");
+}
+
+async function removeIndexFiles(notebook: Notebook) {
+  const root = notebook.root;
+  for await (const entry of walk(root, { match: [/\.index$/] })) {
+    Deno.removeSync(entry.path);
   }
-  commit(notebook, "migrated all markdown entries to ULIDs");
+  commit(notebook, "migrated off .index files");
 }