feat(macros): wrap gen_program output in a hidden module

Move pathf type resolution from `program_final_gen` to `gen_program` and
isolate generated code inside `__this_program_impl` to prevent namespace
pollution

3 files changed, 89 insertions, 35 deletions

diff --git a/mingling_macros/src/func/gen_program.rs b/mingling_macros/src/func/gen_program.rs
index c5358bc..0c35318 100644
--- a/mingling_macros/src/func/gen_program.rs
+++ b/mingling_macros/src/func/gen_program.rs
@@ -15,33 +15,98 @@ pub(crate) fn gen_program_impl(_input: TokenStream) -> TokenStream {
     #[cfg(not(feature = "comp"))]
     let comp_gen = quote! {};
 
+    // When pathf is enabled, load the type_using.rs generated by the build script
+    // and emit its use statements so types from submodules are in scope.
+    #[cfg(feature = "pathf")]
+    let pathf_uses: Vec<proc_macro2::TokenStream> = {
+        let uses = load_pathf_uses();
+        if uses.is_empty() {
+            // The file might not exist yet — emit a clear hint
+            let hint: proc_macro2::TokenStream = syn::parse_quote! {
+                compile_error!(
+                    "pathf: `{}` not found or empty.\n\
+                     Make sure `build.rs` calls `mingling::build::analyze_and_build_type_mapping().unwrap();`\n\
+                     with features [\"build\", \"pathf\"] enabled."
+                );
+            };
+            vec![hint]
+        } else {
+            uses
+        }
+    };
+    #[cfg(not(feature = "pathf"))]
+    let pathf_uses: Vec<proc_macro2::TokenStream> = Vec::new();
+
+    #[cfg(feature = "pathf")]
+    let super_use = quote! {};
+
+    #[cfg(not(feature = "pathf"))]
+    let super_use = quote! {
+      use super::*;
+    };
+
     TokenStream::from(quote! {
-        /// Alias for the current program type `crate::ThisProgram`
-        pub type Next = ::mingling::ChainProcess<crate::ThisProgram>;
-
-        impl ::mingling::Routable<crate::ThisProgram> for ::mingling::ChainProcess<crate::ThisProgram>
-        {
-            fn to_chain(self) -> ::mingling::ChainProcess<crate::ThisProgram> {
-                match self {
-                    ::mingling::ChainProcess::Ok((any, _)) => {
-                        ::mingling::ChainProcess::Ok((any, mingling::NextProcess::Chain))
+        pub use __this_program_impl::*;
+
+        #[doc(hidden)]
+        pub mod __this_program_impl {
+            #super_use
+            #(#pathf_uses)*
+
+            /// Alias for the current program type `ThisProgram`
+            pub type Next = ::mingling::ChainProcess<ThisProgram>;
+
+            impl ::mingling::Routable<ThisProgram> for ::mingling::ChainProcess<ThisProgram>
+            {
+                fn to_chain(self) -> ::mingling::ChainProcess<ThisProgram> {
+                    match self {
+                        ::mingling::ChainProcess::Ok((any, _)) => {
+                            ::mingling::ChainProcess::Ok((any, mingling::NextProcess::Chain))
+                        }
+                        other => other,
                     }
-                    other => other,
                 }
-            }
 
-            fn to_render(self) -> ::mingling::ChainProcess<crate::ThisProgram> {
-                match self {
-                    ::mingling::ChainProcess::Ok((any, _)) => {
-                        ::mingling::ChainProcess::Ok((any, mingling::NextProcess::Renderer))
+                fn to_render(self) -> ::mingling::ChainProcess<ThisProgram> {
+                    match self {
+                        ::mingling::ChainProcess::Ok((any, _)) => {
+                            ::mingling::ChainProcess::Ok((any, mingling::NextProcess::Renderer))
+                        }
+                        other => other,
                     }
-                    other => other,
                 }
             }
-        }
 
-        #comp_gen
-        ::mingling::macros::program_fallback_gen!();
-        ::mingling::macros::program_final_gen!();
+            #comp_gen
+            ::mingling::macros::program_fallback_gen!();
+            ::mingling::macros::program_final_gen!();
+        }
     })
 }
+
+/// Loads `type_using.rs` generated by the pathf build script and returns each
+/// `use ...;` line as a token stream, ready to be emitted in the generated output.
+#[cfg(feature = "pathf")]
+fn load_pathf_uses() -> Vec<proc_macro2::TokenStream> {
+    let out_dir = match std::env::var("OUT_DIR") {
+        Ok(d) => d,
+        Err(_) => return Vec::new(),
+    };
+    let crate_name = match std::env::var("CARGO_PKG_NAME") {
+        Ok(n) => n,
+        Err(_) => return Vec::new(),
+    };
+    let path = std::path::Path::new(&out_dir)
+        .join(&crate_name)
+        .join("type_using.rs");
+    let content = match std::fs::read_to_string(&path) {
+        Ok(c) => c,
+        Err(_) => return Vec::new(),
+    };
+    content
+        .lines()
+        .map(|line| line.trim().to_string())
+        .filter(|line| !line.is_empty())
+        .filter_map(|line| line.parse::<proc_macro2::TokenStream>().ok())
+        .collect()
+}
diff --git a/mingling_macros/src/func/program_comp_gen.rs b/mingling_macros/src/func/program_comp_gen.rs
index b6b2546..2fbb0e0 100644
--- a/mingling_macros/src/func/program_comp_gen.rs
+++ b/mingling_macros/src/func/program_comp_gen.rs
@@ -14,7 +14,7 @@ pub(crate) fn program_comp_gen_impl(_input: TokenStream) -> TokenStream {
             match read_ctx {
                 Ok(ctx) => {
                     let suggest = ::mingling::CompletionHelper::exec_completion::<crate::ThisProgram>(&ctx);
-                    ::mingling::Routable::<crate::ThisProgram>::to_render(crate::CompletionSuggest::new((ctx, suggest)))
+                    ::mingling::Routable::<crate::ThisProgram>::to_render(CompletionSuggest::new((ctx, suggest)))
                 }
                 Err(_) => std::process::exit(1),
             }
@@ -32,7 +32,7 @@ pub(crate) fn program_comp_gen_impl(_input: TokenStream) -> TokenStream {
             match read_ctx {
                 Ok(ctx) => {
                     let suggest = ::mingling::CompletionHelper::exec_completion::<crate::ThisProgram>(&ctx);
-                    ::mingling::Routable::<crate::ThisProgram>::to_render(crate::CompletionSuggest::new((ctx, suggest)))
+                    ::mingling::Routable::<crate::ThisProgram>::to_render(CompletionSuggest::new((ctx, suggest)))
                 }
                 Err(_) => std::process::exit(1),
             }
diff --git a/mingling_macros/src/func/program_final_gen.rs b/mingling_macros/src/func/program_final_gen.rs
index e427f05..0eed1db 100644
--- a/mingling_macros/src/func/program_final_gen.rs
+++ b/mingling_macros/src/func/program_final_gen.rs
@@ -36,8 +36,8 @@ fn parse_entry_pair(entry: &proc_macro2::TokenStream) -> (proc_macro2::Ident, pr
 }
 
 /// Helper: convert a string ident into a token stream for the generated code.
-/// Types are now brought into scope by `gen_program!()` via `include!()` of the
-/// pathf-generated `type_using.rs`, so bare idents suffice.
+/// Types are expected to be in scope (e.g. via pathf glob re-exports), so bare
+/// idents suffice.
 fn ident_tokens(name: &str) -> proc_macro2::TokenStream {
     let ident = proc_macro2::Ident::new(name, proc_macro2::Span::call_site());
     quote! { #ident }
@@ -280,15 +280,6 @@ pub(crate) fn program_final_gen_impl(_input: TokenStream) -> TokenStream {
         quote! { u128 }
     };
 
-    // When pathf is enabled, include the type_using.rs generated by the build
-    // script so that types from submodules are in scope for gen_program!().
-    #[cfg(feature = "pathf")]
-    let pathf_include = quote! {
-        include!(concat!(env!("OUT_DIR"), "/", env!("CARGO_PKG_NAME"), "/type_using.rs"));
-    };
-    #[cfg(not(feature = "pathf"))]
-    let pathf_include = quote! {};
-
     let expanded = quote! {
         #[derive(Debug, PartialEq, Eq, Clone, Copy)]
         #[repr(#repr_type)]
@@ -306,8 +297,6 @@ pub(crate) fn program_final_gen_impl(_input: TokenStream) -> TokenStream {
         }
 
         impl ::mingling::ProgramCollect for #name {
-            #pathf_include
-
             type Enum = #name;
             type ErrorDispatcherNotFound = ErrorDispatcherNotFound;
             type ErrorRendererNotFound = ErrorRendererNotFound;