fix(cli): skip unsupported version of lock file

cli/main.ts

@@ -52,7 +52,7 @@ main.action(async function (options, ...source) {
 
   const lock = options.lock === false
     ? undefined
-    : options.lock ?? await findLock();
+    : await findLock(options.lock);
 
   source = source.length ? source : config ? [] : await findSource();
 

cli/main_test.ts

@@ -118,6 +118,25 @@ describe("CLI", () => {
     );
   });
 
+  it("should ignore an unsupported version of lockfile with a warning", async () => {
+    const { stdout, stderr } = await molt("--lock deno.lock.future");
+    assertEquals(
+      stdout,
+      dedent`
+        📦 @conventional-commits/parser ^0.3.0 → ^0.4.0
+        📦 deno.land/std 0.222.0 → 0.224.0
+      `,
+    );
+    assertEquals(
+      stderr,
+      dedent`
+        Unsupported lockfile version: '4'. Please update the lock file manually.
+        Collecting dependencies
+        Fetching updates
+      `,
+    );
+  });
+
   it("should filter dependencies with `--only`", async () => {
     const { stdout } = await molt("--only flag");
     assertEquals(

cli/src/files.ts

@@ -1,3 +1,4 @@
+import { VERSION } from "@molt/core/locks";
 import { exists } from "@std/fs";
 import { parse } from "@std/jsonc";
 
@@ -16,10 +17,19 @@ async function hasImports(config: string): Promise<boolean> {
   return jsonc !== null && typeof jsonc === "object" && "imports" in jsonc;
 }
 
-export async function findLock() {
-  if (await exists("deno.lock")) {
-    return "deno.lock";
+export async function findLock(path?: string) {
+  path ??= await exists("deno.lock") ? "deno.lock" : undefined;
+  if (!path) {
+    return;
   }
+  const { version } = JSON.parse(await Deno.readTextFile(path));
+  if (version !== VERSION) {
+    console.warn(
+      `Unsupported lockfile version: '${version}'. Please update the lock file manually.`,
+    );
+    return;
+  }
+  return path;
 }
 
 export async function findSource() {