Fix Display proc macro, revert some changes, update test

Signed-off-by: Patrik Stas <patrik.stas@absa.africa>

aries/messages/src/msg_fields/protocols/coordinate_mediation/keylist_query.rs

@@ -1,10 +1,10 @@
 use serde::{Deserialize, Serialize};
 use typed_builder::TypedBuilder;
 
-use crate::{decorators::thread::Thread, misc::NoDecorators, msg_parts::MsgParts};
+use crate::{decorators::thread::Thread, msg_parts::MsgParts};
 
 /// https://github.com/hyperledger/aries-rfcs/blob/main/features/0211-route-coordination/README.md#key-list-query
-pub type KeylistQuery = MsgParts<KeylistQueryContent, NoDecorators>;
+pub type KeylistQuery = MsgParts<KeylistQueryContent>;
 
 #[derive(Clone, Debug, Deserialize, Serialize, Default, PartialEq, TypedBuilder)]
 pub struct KeylistQueryContent {

aries/messages/src/msg_fields/protocols/coordinate_mediation/keylist_update.rs

@@ -1,10 +1,10 @@
 use serde::{Deserialize, Serialize};
 use typed_builder::TypedBuilder;
 
-use crate::{decorators::thread::Thread, misc::NoDecorators, msg_parts::MsgParts};
+use crate::{decorators::thread::Thread, msg_parts::MsgParts};
 
 /// https://github.com/hyperledger/aries-rfcs/blob/main/features/0211-route-coordination/README.md#keylist-update
-pub type KeylistUpdate = MsgParts<KeylistUpdateContent, NoDecorators>;
+pub type KeylistUpdate = MsgParts<KeylistUpdateContent>;
 
 #[derive(Clone, Debug, Deserialize, Serialize, Default, PartialEq, TypedBuilder)]
 pub struct KeylistUpdateContent {

aries/messages/src/msg_fields/protocols/coordinate_mediation/mediate_request.rs

@@ -1,10 +1,10 @@
 use serde::{Deserialize, Serialize};
 use typed_builder::TypedBuilder;
 
-use crate::{decorators::thread::Thread, misc::NoDecorators, msg_parts::MsgParts};
+use crate::{decorators::thread::Thread, msg_parts::MsgParts};
 
 /// https://github.com/hyperledger/aries-rfcs/blob/main/features/0211-route-coordination/README.md#mediation-request
-pub type MediateRequest = MsgParts<MediateRequestContent, NoDecorators>;
+pub type MediateRequest = MsgParts<MediateRequestContent>;
 
 #[derive(Clone, Debug, Deserialize, Serialize, Default, PartialEq, TypedBuilder)]
 pub struct MediateRequestContent {}

aries/messages/src/msg_fields/protocols/routing.rs

@@ -5,12 +5,11 @@ use serde_json::Value;
 use typed_builder::TypedBuilder;
 
 use crate::{
-    misc::{utils::into_msg_with_type, NoDecorators},
-    msg_parts::MsgParts,
+    misc::utils::into_msg_with_type, msg_parts::MsgParts,
     msg_types::protocols::routing::RoutingTypeV1_0,
 };
 
-pub type Forward = MsgParts<ForwardContent, NoDecorators>;
+pub type Forward = MsgParts<ForwardContent>;
 
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq, TypedBuilder)]
 pub struct ForwardContent {

aries/messages/src/msg_parts.rs

@@ -1,6 +1,6 @@
 use display_as_json::Display;
 use serde::{Deserialize, Serialize};
-// Bind `shared::misc::serde_ignored::SerdeIgnored` type as `NoDecorators`.
+use shared::misc::serde_ignored::SerdeIgnored as NoDecorators;
 use typed_builder::TypedBuilder;
 
 /// Struct representing a complete message (apart from the `@type` field) as defined in a protocol
@@ -16,7 +16,7 @@ use typed_builder::TypedBuilder;
 /// `~timing`).
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq, TypedBuilder, Display)]
 #[builder(build_method(vis = "", name = __build))]
-pub struct MsgParts<C, D> {
+pub struct MsgParts<C, D = NoDecorators> {
     /// All standalone messages have an `id` field.
     #[serde(rename = "@id")]
     pub id: String,
@@ -81,8 +81,8 @@ pub mod tests {
             .content(request_content())
             .decorators(RequestDecorators::default())
             .build();
-        let printed = format!("{}", msg);
-        let expected = r#"{"@id":"test_id","label":"test_request_label","goal_code":"aries.rel.build","goal":"test_goal","did":"","did_doc~attach":{"data":{"json":{"@context":"https://w3id.org/did/v1","authentication":[],"id":"","publicKey":[],"service":[{"id":"did:example:123456789abcdefghi;indy","priority":0,"recipientKeys":[],"routingKeys":[],"serviceEndpoint":"https://dummy.dummy/dummy","type":"IndyAgent"}]}}}}"#;
-        assert_eq!(expected, printed);
+        let printed_json = format!("{}", msg);
+        let parsed_request: Request = serde_json::from_str(&printed_json).unwrap();
+        assert_eq!(msg, parsed_request);
     }
 }

misc/display_as_json/src/lib.rs

@@ -13,25 +13,35 @@ fn impl_display(ast: &syn::DeriveInput) -> TokenStream {
     let name = &ast.ident;
     let generics = &ast.generics;
 
-    // Create new where clause with Serialize bounds for each generic type
-    let where_clause = generics.params.iter().map(|param| {
-        let ident = match param {
-            syn::GenericParam::Type(type_param) => &type_param.ident,
-            _ => return quote!(), // Skip non-type parameters
-        };
-        quote! { #ident: serde::Serialize }
+    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
+
+    // For each of the generics parameter G, we prepare addition trait bound "G: serde::Serialize"
+    let serialize_bounds = generics.params.iter().filter_map(|param| {
+        match param {
+            syn::GenericParam::Type(type_param) => {
+                let ident = &type_param.ident;
+                Some(quote! { #ident: serde::Serialize })
+            },
+            _ => None, // Skip non-type parameters, eg lifetimes
+        }
     });
 
+    // Combine the original where clause with additional bounds we prepared above
+    // See quote! macro docs for more info on the #() syntax https://docs.rs/quote/1.0.33/quote/macro.quote.html
+    let combined_where_clause = if where_clause.is_none() {
+        quote! { where #(#serialize_bounds),* }
+    } else {
+        quote! { #where_clause, #(#serialize_bounds),* }
+    };
+
+    // Generate the actual impl
     let gen = quote! {
-        impl #generics std::fmt::Display for #name #generics
-        where
-            #(#where_clause),*
-        {
+        impl #impl_generics std::fmt::Display for #name #ty_generics #combined_where_clause {
             fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-                let json = serde_json::to_string(self).unwrap_or_else(|e| {
-                    format!("Error serializing {}: {}", stringify!(#name), e)
-                });
-                write!(f, "{}", json)
+                match serde_json::to_string(self) {
+                    Ok(json) => write!(f, "{}", json),
+                    Err(e) => write!(f, "Error serializing {}: {}", stringify!(#name), e),
+                }
             }
         }
     };