fix(ai): 自选 provider 的追问建议改用用户自己的模型，不再落进公共缓存

条件写成 provider !== "intern" && !ZHIPU_API_KEY，线上配了 ZHIPU，于是选了
openai/gemini 并填了自己 key 的用户也走公共缓存分支，cache 里固定用 intern/glm，
用户的 key 和模型被丢掉，和注释「自定义 key 不走公共缓存」相反。

Author: github-actions[bot]

app/api/suggestions/route.ts

@@ -120,20 +120,15 @@ export async function POST(req: Request) {
 
     let text = "";
     // 判断是否可以使用缓存（如果使用了自定义 apiKey，为了防止数据交叉，不采用公用缓存）
-    if (provider !== "intern" && !process.env.ZHIPU_API_KEY) {
+    if (provider !== "intern") {
       const { text: directText } = await generateText({
         model,
         prompt,
       });
       text = directText;
     } else {
       // 确定内部用于缓存匹配的模型标识
-      const internalModelId =
-        provider === "intern"
-          ? process.env.ZHIPU_API_KEY
-            ? "glm"
-            : "intern"
-          : "intern";
+      const internalModelId = process.env.ZHIPU_API_KEY ? "glm" : "intern";
       // 将缓存粒度关联到请求本身的内容上
       const suggestionKey = isWelcomeRequest
         ? `welcome-${pageContext?.slug || "default"}`

tests/suggestions-route.test.ts

@@ -0,0 +1,67 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+const generateText = vi.fn(async () => ({ text: '["q1","q2","q3"]' }));
+const unstableCache = vi.fn(
+  (fn: (...args: unknown[]) => unknown, _keys?: string[], _opts?: object) =>
+    (...args: unknown[]) =>
+      fn(...args),
+);
+
+vi.mock("ai", () => ({ generateText }));
+vi.mock("next/cache", () => ({ unstable_cache: unstableCache }));
+vi.mock("@/lib/rate-limit", () => ({
+  limitChat: async () => ({ success: true }),
+  rateLimitResponse: () => new Response(null, { status: 429 }),
+}));
+vi.mock("@/lib/ai/models", () => ({
+  getModel: (provider: string, apiKey?: string) => ({ provider, apiKey }),
+  requiresApiKey: (provider: string) => provider !== "intern",
+}));
+vi.mock("@/lib/ai/providers/glm", () => ({
+  createGlmFlashModel: () => ({ provider: "glm" }),
+}));
+
+const { POST } = await import("@/app/api/suggestions/route");
+
+// 公共缓存按请求建一层 unstable_cache，key 形如 suggestion-key-<...>
+const usedSharedCache = () =>
+  unstableCache.mock.calls.some(([, keys]) =>
+    (keys as string[]).some((k) => k.startsWith("suggestion-key-")),
+  );
+
+function post(body: object) {
+  return POST(
+    new Request("http://localhost/api/suggestions", {
+      method: "POST",
+      body: JSON.stringify(body),
+    }),
+  );
+}
+
+describe("/api/suggestions 模型选择", () => {
+  beforeEach(() => vi.stubEnv("ZHIPU_API_KEY", "server-key"));
+  afterEach(() => {
+    vi.unstubAllEnvs();
+    vi.clearAllMocks();
+  });
+
+  it("自带 key 的 provider 用用户自己的模型，不进公共缓存（即使服务端配了 ZHIPU）", async () => {
+    await post({ messages: [], provider: "openai", apiKey: "user-key" });
+
+    expect(usedSharedCache()).toBe(false);
+    expect(generateText).toHaveBeenCalledWith(
+      expect.objectContaining({
+        model: { provider: "openai", apiKey: "user-key" },
+      }),
+    );
+  });
+
+  it("默认 intern 走公共缓存，配了 ZHIPU 时用 GLM", async () => {
+    await post({ messages: [] });
+
+    expect(usedSharedCache()).toBe(true);
+    expect(generateText).toHaveBeenCalledWith(
+      expect.objectContaining({ model: { provider: "glm" } }),
+    );
+  });
+});