common: Add DebugAsRefStr derive macro

crates/ruma-common/CHANGELOG.md

@@ -79,6 +79,7 @@ Improvements:
 * Add support for bundled reference relations (MSC3267 / Matrix 1.5)
 * Add the `formatted` field on `KeyVerificationRequestEventContent` (Matrix 1.5)
 * Add `content` accessors for `Any*StateEvent` enums
+* Add the `DebugAsRefStr` derive macro to `ruma_common::serde`
 
 # 0.10.5
 

crates/ruma-common/src/serde.rs

@@ -73,6 +73,6 @@ where
 }
 
 pub use ruma_macros::{
-    AsRefStr, DeserializeFromCowStr, DisplayAsRefStr, FromString, OrdAsRefStr, PartialEqAsRefStr,
-    PartialOrdAsRefStr, SerializeAsRefStr, StringEnum, _FakeDeriveSerde,
+    AsRefStr, DebugAsRefStr, DeserializeFromCowStr, DisplayAsRefStr, FromString, OrdAsRefStr,
+    PartialEqAsRefStr, PartialOrdAsRefStr, SerializeAsRefStr, StringEnum, _FakeDeriveSerde,
 };

crates/ruma-macros/src/lib.rs

@@ -39,6 +39,7 @@ use self::{
     identifiers::IdentifierInput,
     serde::{
         as_str_as_ref_str::expand_as_str_as_ref_str,
+        debug_as_ref_str::expand_debug_as_ref_str,
         deserialize_from_cow_str::expand_deserialize_from_cow_str,
         display_as_ref_str::expand_display_as_ref_str,
         enum_as_ref_str::expand_enum_as_ref_str,
@@ -291,6 +292,13 @@ pub fn derive_display_as_ref_str(input: TokenStream) -> TokenStream {
     expand_display_as_ref_str(&input.ident).unwrap_or_else(syn::Error::into_compile_error).into()
 }
 
+/// Derive the `fmt::Debug` trait using the `AsRef<str>` implementation of the type.
+#[proc_macro_derive(DebugAsRefStr)]
+pub fn derive_debug_as_ref_str(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    expand_debug_as_ref_str(&input.ident).unwrap_or_else(syn::Error::into_compile_error).into()
+}
+
 /// Derive the `Serialize` trait using the `AsRef<str>` implementation of the type.
 #[proc_macro_derive(SerializeAsRefStr)]
 pub fn derive_serialize_as_ref_str(input: TokenStream) -> TokenStream {

crates/ruma-macros/src/serde.rs

@@ -3,6 +3,7 @@
 pub mod as_str_as_ref_str;
 pub mod attr;
 pub mod case;
+pub mod debug_as_ref_str;
 pub mod deserialize_from_cow_str;
 pub mod display_as_ref_str;
 pub mod enum_as_ref_str;

crates/ruma-macros/src/serde/debug_as_ref_str.rs

@@ -0,0 +1,17 @@
+use proc_macro2::{Ident, TokenStream};
+use quote::quote;
+
+pub fn expand_debug_as_ref_str(ident: &Ident) -> syn::Result<TokenStream> {
+    Ok(quote! {
+        #[automatically_derived]
+        #[allow(deprecated)]
+        impl ::std::fmt::Debug for #ident {
+            fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
+                <::std::primitive::str as ::std::fmt::Debug>::fmt(
+                    ::std::convert::AsRef::<::std::primitive::str>::as_ref(self),
+                    f,
+                )
+            }
+        }
+    })
+}