Fix default export and exported function expressions handling of cache directive transform (#71334)

This PR fixes the transform of handling `export default async function()
{}` and `export const foo = async function() {}` cases (both are
exported `fnExpr`, instead of `fnDecl`) in a `"use cache"` annotated
file.

Author: shuding

crates/next-custom-transforms/src/transforms/server_actions.rs

@@ -895,40 +895,38 @@ impl<C: Comments> VisitMut for ServerActions<C> {
         }
 
         if let Some(cache_type_str) = cache_type {
-            if !(self.in_cache_file.is_some() && self.in_export_decl) {
-                // It's a cache function. If it doesn't have a name, give it one.
-                match f.ident.as_mut() {
-                    None => {
-                        let action_name = gen_cache_ident(&mut self.reference_index);
-                        let ident = Ident::new(action_name, DUMMY_SP, Default::default());
-                        f.ident.insert(ident)
-                    }
-                    Some(i) => i,
-                };
+            // It's a cache function. If it doesn't have a name, give it one.
+            match f.ident.as_mut() {
+                None => {
+                    let action_name = gen_cache_ident(&mut self.reference_index);
+                    let ident = Ident::new(action_name, DUMMY_SP, Default::default());
+                    f.ident.insert(ident)
+                }
+                Some(i) => i,
+            };
 
-                // Collect all the identifiers defined inside the closure and used
-                // in the cache function. With deduplication.
-                retain_names_from_declared_idents(
-                    &mut child_names,
-                    &self.declared_idents[..declared_idents_until],
-                );
+            // Collect all the identifiers defined inside the closure and used
+            // in the cache function. With deduplication.
+            retain_names_from_declared_idents(
+                &mut child_names,
+                &self.declared_idents[..declared_idents_until],
+            );
 
-                let new_expr = self.maybe_hoist_and_create_proxy_for_cache_function(
-                    child_names.clone(),
-                    f.ident.clone(),
-                    cache_type_str.as_str(),
-                    &mut f.function,
-                );
+            let new_expr = self.maybe_hoist_and_create_proxy_for_cache_function(
+                child_names.clone(),
+                f.ident.clone(),
+                cache_type_str.as_str(),
+                &mut f.function,
+            );
 
-                if self.in_default_export_decl {
-                    // This function expression is also the default export:
-                    // `export default async function() {}`
-                    // This specific case (default export) isn't handled by `visit_mut_expr`.
-                    // Replace the original function expr with a action proxy expr.
-                    self.rewrite_default_fn_expr_to_proxy_expr = Some(new_expr);
-                } else {
-                    self.rewrite_expr_to_proxy_expr = Some(new_expr);
-                }
+            if self.in_default_export_decl {
+                // This function expression is also the default export:
+                // `export default async function() {}`
+                // This specific case (default export) isn't handled by `visit_mut_expr`.
+                // Replace the original function expr with a action proxy expr.
+                self.rewrite_default_fn_expr_to_proxy_expr = Some(new_expr);
+            } else {
+                self.rewrite_expr_to_proxy_expr = Some(new_expr);
             }
         }
 

crates/next-custom-transforms/tests/fixture/server-actions/server/36/input.js

@@ -7,3 +7,11 @@ export async function foo() {
 export async function bar() {
   return 'data B'
 }
+
+export default async function Cached({ children }) {
+  return children
+}
+
+export const baz = async function () {
+  return 'data C'
+}

crates/next-custom-transforms/tests/fixture/server-actions/server/36/output.js

@@ -1,4 +1,4 @@
-/* __next_internal_action_entry_do_not_use__ {"3128060c414d59f8552e4788b846c0d2b7f74743":"$$RSC_SERVER_CACHE_0","951c375b4a6a6e89d67b743ec5808127cfde405d":"$$RSC_SERVER_CACHE_1"} */ import { registerServerReference } from "private-next-rsc-server-reference";
+/* __next_internal_action_entry_do_not_use__ {"3128060c414d59f8552e4788b846c0d2b7f74743":"$$RSC_SERVER_CACHE_0","4acc55633206134002149ce873fe498be64a6fef":"$$RSC_SERVER_CACHE_4","69348c79fce073bae2f70f139565a2fda1c74c74":"$$RSC_SERVER_CACHE_2","951c375b4a6a6e89d67b743ec5808127cfde405d":"$$RSC_SERVER_CACHE_1"} */ import { registerServerReference } from "private-next-rsc-server-reference";
 import { encryptActionBoundArgs, decryptActionBoundArgs } from "private-next-rsc-action-encryption";
 import { cache as $$cache__ } from "private-next-rsc-cache-wrapper";
 export var $$RSC_SERVER_CACHE_0 = $$cache__("default", "3128060c414d59f8552e4788b846c0d2b7f74743", async function foo() {
@@ -9,3 +9,11 @@ export var $$RSC_SERVER_CACHE_1 = $$cache__("default", "951c375b4a6a6e89d67b743e
     return 'data B';
 });
 export var bar = registerServerReference($$RSC_SERVER_CACHE_1, "951c375b4a6a6e89d67b743ec5808127cfde405d", null);
+export var $$RSC_SERVER_CACHE_2 = $$cache__("default", "69348c79fce073bae2f70f139565a2fda1c74c74", async function Cached({ children }) {
+    return children;
+});
+export default registerServerReference($$RSC_SERVER_CACHE_2, "69348c79fce073bae2f70f139565a2fda1c74c74", null);
+export var $$RSC_SERVER_CACHE_4 = $$cache__("default", "4acc55633206134002149ce873fe498be64a6fef", async function $$RSC_SERVER_CACHE_3() {
+    return 'data C';
+});
+export const baz = registerServerReference($$RSC_SERVER_CACHE_4, "4acc55633206134002149ce873fe498be64a6fef", null);