Merge pull request #4 from risingwavelabs/bz/macro-vis

derive/src/expand.rs

@@ -135,6 +135,7 @@ struct DeriveMeta {
     nt_report_debug: bool,
     macro_mangle: bool,
     macro_path: Option<TokenStream>,
+    macro_vis: Option<Visibility>,
 }
 
 fn resolve_meta(input: &DeriveInput) -> Result<DeriveMeta> {
@@ -143,6 +144,7 @@ fn resolve_meta(input: &DeriveInput) -> Result<DeriveMeta> {
     let mut nt_report_debug = false;
     let mut macro_mangle = false;
     let mut macro_path = None;
+    let mut macro_vis = None;
 
     for attr in &input.attrs {
         if attr.path().is_ident("thiserror_ext") {
@@ -182,6 +184,13 @@ fn resolve_meta(input: &DeriveInput) -> Result<DeriveMeta> {
                                     "macro path should start with `crate`",
                                 ));
                             }
+                        } else if meta.path.is_ident("vis") {
+                            let value = meta.value()?;
+                            macro_vis = Some(if let Ok(lit_str) = value.parse::<LitStr>() {
+                                lit_str.parse()?
+                            } else {
+                                value.parse()?
+                            })
                         } else {
                             return Err(Error::new_spanned(meta.path, "unknown attribute"));
                         }
@@ -202,6 +211,7 @@ fn resolve_meta(input: &DeriveInput) -> Result<DeriveMeta> {
         nt_report_debug,
         macro_mangle,
         macro_path,
+        macro_vis,
     })
 }
 
@@ -519,16 +529,16 @@ pub fn derive_ctor(input: &DeriveInput, t: DeriveCtorType) -> Result<TokenStream
 }
 
 pub fn derive_macro_inner(input: &DeriveInput, bail: bool) -> Result<TokenStream> {
-    let input_type = input.ident.clone();
-    let vis = &input.vis;
-
     let DeriveMeta {
         impl_type,
         macro_mangle,
         macro_path,
+        macro_vis,
         ..
     } = resolve_meta(input)?;
 
+    let input_type = input.ident.clone();
+    let vis = macro_vis.unwrap_or_else(|| input.vis.clone());
     let input = Input::from_syn(input)?;
 
     let variants = match input {

derive/src/lib.rs

@@ -168,12 +168,13 @@ pub fn derive_context_into(input: TokenStream) -> TokenStream {
 ///
 /// There's a different rule set for the visibility of the macros. The macros
 /// generated by this proc-macro are marked with `#[macro_export]` only if the
-/// visibility of the error type is `pub`, or they're just re-exported with
-/// the same visibility as the error type and only work in the same crate.
+/// visibility of the error type is `pub`, otherwise they're just re-exported
+/// with the same visibility as the error type and only work in the same crate.
 ///
 /// There're some extra configurations to help to better handle the visibility,
 /// specified in `#[thiserror_ext(macro(..))]`:
 ///
+/// - `vis = ..`: use a different visibility for the macro re-export.
 /// - `mangle`: mangle the macro names so that they don't conflict with other
 ///   macros with the same name in the crate root.
 /// - `path = "crate::.."`: the path to the current module. When specified,

tests/macro.rs

@@ -33,7 +33,7 @@ pub mod inner {
     }
     #[derive(Error, Debug, Macro)]
     #[error("not implemented: {message}, issue: {issue:?}")]
-    #[thiserror_ext(macro(mangle, path = "crate::inner"))]
+    #[thiserror_ext(macro(mangle, path = "crate::inner", vis = pub(super)))]
     pub struct NotImplemented {
         pub issue: Option<i32>,
         pub message: String,