revert: cache the models.dev directory on disk (#1817)

docs/src/content/docs/docs/AIAssistant.md

@@ -178,12 +178,6 @@ window, output limit, and sampling support where the source reports them.
 If model import fails, you can still add models manually. Use the provider's
 exact model id and the model's context-window token count.
 
-QuickAdd saves the models.dev directory (about 5 MB) as `models-dev-cache.json`
-in its plugin folder. On later launches it asks models.dev whether the directory
-changed and downloads it again only when it did. If models.dev is unreachable,
-QuickAdd uses the saved copy. Deleting the file is safe; QuickAdd downloads it
-again the next time it needs it.
-
 ### Keep model lists current: Auto-sync {#auto-sync}
 
 Each provider has an **Auto-sync models** toggle. While it is on, QuickAdd

src/ai/modelsDirectory.fetch.test.ts

@@ -0,0 +1,79 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const storeState = vi.hoisted(() => ({ disableOnlineFeatures: false }));
+const requestUrlMock = vi.hoisted(() => vi.fn());
+
+vi.mock("obsidian", async (importOriginal) => ({
+	...(await importOriginal<typeof import("obsidian")>()),
+	requestUrl: requestUrlMock,
+}));
+
+vi.mock("src/settingsStore", () => ({
+	settingsStore: { getState: () => storeState },
+}));
+
+const VALID = {
+	openai: {
+		id: "openai",
+		name: "OpenAI",
+		models: { "gpt-a": { id: "gpt-a" } },
+	},
+};
+
+/** Fresh module = empty memory cache (as after an Obsidian restart). */
+async function loadFetch() {
+	vi.resetModules();
+	const mod = await import("./modelsDirectory");
+	return mod.fetchModelsDevDirectory;
+}
+
+describe("fetchModelsDevDirectory validation", () => {
+	beforeEach(() => {
+		requestUrlMock.mockReset();
+		storeState.disableOnlineFeatures = false;
+	});
+
+	it("caches a valid directory for the session", async () => {
+		const fetch = await loadFetch();
+		requestUrlMock.mockResolvedValueOnce({ status: 200, json: VALID });
+
+		expect(await fetch()).toEqual(VALID);
+		expect(await fetch()).toEqual(VALID);
+		expect(requestUrlMock).toHaveBeenCalledTimes(1);
+	});
+
+	it.each([
+		["an array body", []],
+		["an empty object", {}],
+		["a provider without models", { openai: { id: "openai", name: "OpenAI" } }],
+	])("rejects %s without poisoning the memory cache", async (_label, body) => {
+		const fetch = await loadFetch();
+		requestUrlMock
+			.mockResolvedValueOnce({ status: 200, json: body })
+			.mockResolvedValueOnce({ status: 200, json: VALID });
+
+		await expect(fetch()).rejects.toThrow(/unexpected response/);
+		expect(await fetch()).toEqual(VALID);
+		expect(requestUrlMock).toHaveBeenCalledTimes(2);
+	});
+
+	it("drops only the malformed providers and keeps the rest", async () => {
+		const fetch = await loadFetch();
+		const body = {
+			...VALID,
+			broken: { id: "broken", name: "Broken" },
+			nullModels: { id: "nullModels", name: "Null", models: null },
+		};
+		requestUrlMock.mockResolvedValueOnce({ status: 200, json: body });
+
+		expect(await fetch()).toEqual(VALID);
+	});
+
+	it("keeps the online-features gate", async () => {
+		const fetch = await loadFetch();
+		storeState.disableOnlineFeatures = true;
+
+		await expect(fetch()).rejects.toThrow(/Online features are turned off/);
+		expect(requestUrlMock).not.toHaveBeenCalled();
+	});
+});