next.js

59fe222b - Convert any export from a `'use cache'` module to a cache function (#86014)

Convert any export from a `'use cache'` module to a cache function (#86014) Previously, in a `'use cache'` module, we only compiled statically-known exported functions and arrow expressions to cache functions. Now, we also compile re-exports and exports of values that might be functions. This includes exports like: - `export { getData } from './data'` - re-exporting from another module - `export const aliased = getData` - exporting an imported identifier - `const Page = withSlug(...); export default Page` - exporting the result of a function call These cases can't be statically verified as functions at compile time, so we generate runtime wrappers with `typeof === "function"` checks (simplified): ```js let $$RSC_SERVER_CACHE_getData = getData; if (typeof getData === "function") { $$RSC_SERVER_CACHE_getData = React.cache(function() { return cache("default", "...", 0, getData, arguments); }); registerServerReference($$RSC_SERVER_CACHE_getData, "...", null); Object.defineProperty($$RSC_SERVER_CACHE_getData, "name", { value: "getData" }); } export { $$RSC_SERVER_CACHE_getData as getData }; ``` This ensures that all function exports from `'use cache'` modules are properly cached, while non-function exports pass through unchanged. This approach comes with some limitations compared to statically-known function exports: 1. **No compile-time type checking:** We can't verify that these exports are actually functions. Non-function exports will be passed through as-is at runtime. 2. **No async enforcement:** We can't enforce that functions must be async (as we do for statically-known functions). Synchronous functions are supported, but will lie about their type signature. They become async after being wrapped as cache functions, even though their original signature was synchronous. closes NAR-196