Extract the #[serde(rename = "...")] codegen logic to the shared module

Author: tomhoule

graphql_query_derive/src/inputs.rs

@@ -24,11 +24,7 @@ impl GqlInput {
             let ty = field.type_.to_rust(&context, "");
             let original_name = &field.name;
             let snake_case_name = field.name.to_snake_case();
-            let rename = if snake_case_name.as_str() != original_name.as_str() {
-                quote!(#[serde(rename = #original_name)])
-            } else {
-                quote!()
-            };
+            let rename = ::shared::field_rename_annotation(&original_name, &snake_case_name);
             let name = Ident::new(&snake_case_name, Span::call_site());
 
             quote!(#rename pub #name: #ty)

graphql_query_derive/src/operations.rs

@@ -51,12 +51,9 @@ impl Operation {
             let name = &variable.name;
             let ty = variable.ty.to_rust(context, "");
             let snake_case_name = name.to_snake_case();
-            let rename = if snake_case_name.as_str() != name.as_str() {
-                quote!(#[serde(rename = #name)])
-            } else {
-                quote!()
-            };
+            let rename = ::shared::field_rename_annotation(&name, &snake_case_name);
             let name = Ident::new(&snake_case_name, Span::call_site());
+
             quote!(#rename pub #name: #ty)
         });
 

graphql_query_derive/src/shared.rs

@@ -21,13 +21,7 @@ pub(crate) fn render_object_field(
     }
 
     let snake_case_name = field_name.to_snake_case();
-
-    let rename = if snake_case_name != field_name {
-        quote!(#[serde(rename = #field_name)])
-    } else {
-        quote!()
-    };
-
+    let rename = ::shared::field_rename_annotation(&field_name, &snake_case_name);
     let name_ident = Ident::new(&snake_case_name, Span::call_site());
 
     quote!(#description #rename pub #name_ident: #field_type)
@@ -104,3 +98,14 @@ pub(crate) fn response_fields_for_selection(
             }
         }).collect()
 }
+
+/// Given the GraphQL schema name for an object/interface/input object field and
+/// the equivalent rust name, produces a serde annotation to map them during
+/// (de)serialization if it is necessary, otherwise an empty TokenStream.
+pub(crate) fn field_rename_annotation(graphql_name: &str, rust_name: &str) -> TokenStream {
+    if graphql_name != rust_name {
+        quote!(#[serde(rename = #graphql_name)])
+    } else {
+        quote!()
+    }
+}