feat: forwards-compatibility for handler visibility inheritance fix (#3391)

actix-web-codegen/CHANGES.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 - Add `#[scope]` macro.
+- Add `compat-routing-macros-force-pub` crate feature which, on-by-default, which when disabled causes handlers to inherit their attached function's visibility.
 - Prevent inclusion of default `actix-router` features.
 - Minimum supported Rust version (MSRV) is now 1.72.
 

actix-web-codegen/Cargo.toml

@@ -15,6 +15,10 @@ rust-version.workspace = true
 [lib]
 proc-macro = true
 
+[features]
+default = ["compat-routing-macros-force-pub"]
+compat-routing-macros-force-pub = []
+
 [dependencies]
 actix-router = { version = "0.5", default-features = false }
 proc-macro2 = "1"

actix-web-codegen/src/route.rs

@@ -413,6 +413,13 @@ impl ToTokens for Route {
             doc_attributes,
         } = self;
 
+        #[allow(unused_variables)] // used when force-pub feature is disabled
+        let vis = &ast.vis;
+
+        // TODO(breaking): remove this force-pub forwards-compatibility feature
+        #[cfg(feature = "compat-routing-macros-force-pub")]
+        let vis = syn::Visibility::Public(<Token![pub]>::default());
+
         let registrations: TokenStream2 = args
             .iter()
             .map(|args| {
@@ -460,7 +467,7 @@ impl ToTokens for Route {
         let stream = quote! {
             #(#doc_attributes)*
             #[allow(non_camel_case_types, missing_docs)]
-            pub struct #name;
+            #vis struct #name;
 
             impl ::actix_web::dev::HttpServiceFactory for #name {
                 fn register(self, __config: &mut actix_web::dev::AppService) {

actix-web-codegen/tests/scopes.rs

@@ -49,7 +49,7 @@ mod scope_module {
     #[connect("/test2")]
     #[options("/test3")]
     #[trace("/test4")]
-    async fn multiple_separate_paths() -> impl Responder {
+    pub async fn multiple_separate_paths() -> impl Responder {
         HttpResponse::Ok().finish()
     }