fix: reliable file manager saves with sudo prompt and no base64 guessing (#1335)

plugins/file-manager/tests/backend/write-content.test.ts

@@ -0,0 +1,21 @@
+import { describe, expect, it } from "vitest";
+import { decodeWriteContent } from "../../src/backend/content-routes.js";
+
+describe("decodeWriteContent", () => {
+  it("keeps text that happens to be valid base64", () => {
+    expect(decodeWriteContent("test").toString("utf8")).toBe("test");
+    expect(decodeWriteContent("abcd1234").toString("utf8")).toBe("abcd1234");
+  });
+
+  it("decodes base64 only when asked", () => {
+    const encoded = Buffer.from("local x = 1\n").toString("base64");
+    expect(decodeWriteContent(encoded, "base64").toString("utf8")).toBe(
+      "local x = 1\n",
+    );
+  });
+
+  it("passes buffers through", () => {
+    const buffer = Buffer.from([0, 1, 2]);
+    expect(decodeWriteContent(buffer)).toBe(buffer);
+  });
+});