wrapLanguageModel doesn't validate object schema

[so-shiba]

Description

The official documentation for caching https://ai-sdk.dev/docs/advanced/caching uses wrapLanguageModel to intercept doGenerate call. However, doGenerate doesn't validate the object with json schema. Therefore, if doGenerate returns a AI response with invalid json, it's still being cached and the generateObject will fail consistently

AI SDK Version

export const cacheMiddleware: LanguageModelV2Middleware = {
wrapGenerate: async ({ doGenerate, params }) => {
const cacheKey = JSON.stringify(params);

const cached = (await redis.get(cacheKey)) as Awaited<
  ReturnType<LanguageModelV2['doGenerate']>
> | null;

if (cached !== null) {
  return {
    ...cached,
    response: {
      ...cached.response,
      timestamp: cached?.response?.timestamp
        ? new Date(cached?.response?.timestamp)
        : undefined,
    },
  };
}

const result = await doGenerate();

redis.set(cacheKey, result);

return result;

},
}

This happens on all versions of ai sdk

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