Add support for lifetime annotations when using derives (#226)

Fixes https://github.com/graphql-rust/juniper/issues/225

changelog/master.md

@@ -45,10 +45,16 @@
 
   [#219](https://github.com/graphql-rust/juniper/pull/219)
 
+
+* The `GraphQLObject` and `GraphQLInputObject` custom derives
+  now support lifetime annotations.
+
+  [#225](https://github.com/graphql-rust/juniper/issues/225)
+
 * When using the `GraphQLObject` custom derive, fields now be omitted by annotating the field with `#[graphql(skip)]`.
 
   [#220](https://github.com/graphql-rust/juniper/issues/220)
 
 * Due to newer dependencies, the oldest Rust version supported is now 1.22.0
 
-  [#231](https://github.com/graphql-rust/juniper/pull/231)
+  [#231](https://github.com/graphql-rust/juniper/pull/231)

juniper_codegen/src/derive_input_object.rs

@@ -132,6 +132,7 @@ pub fn impl_input_object(ast: &syn::DeriveInput) -> TokenStream {
     let ident = &ast.ident;
     let attrs = ObjAttrs::from_input(ast);
     let name = attrs.name.unwrap_or(ast.ident.to_string());
+    let generics = &ast.generics;
 
     let meta_description = match attrs.description {
         Some(descr) => quote!{ let meta = meta.description(#descr); },
@@ -240,7 +241,7 @@ pub fn impl_input_object(ast: &syn::DeriveInput) -> TokenStream {
     }
 
     let body = quote! {
-        impl _juniper::GraphQLType for #ident {
+        impl #generics _juniper::GraphQLType for #ident #generics {
             type Context = ();
             type TypeInfo = ();
 
@@ -261,8 +262,8 @@ pub fn impl_input_object(ast: &syn::DeriveInput) -> TokenStream {
             }
         }
 
-        impl _juniper::FromInputValue for #ident {
-            fn from_input_value(value: &_juniper::InputValue) -> Option<#ident> {
+        impl #generics _juniper::FromInputValue for #ident #generics {
+            fn from_input_value(value: &_juniper::InputValue) -> Option<#ident #generics> {
                 if let Some(obj) = value.to_object_value() {
                     let item = #ident {
                         #(#from_inputs)*
@@ -275,7 +276,7 @@ pub fn impl_input_object(ast: &syn::DeriveInput) -> TokenStream {
             }
         }
 
-        impl _juniper::ToInputValue for #ident {
+        impl #generics _juniper::ToInputValue for #ident #generics {
             fn to_input_value(&self) -> _juniper::InputValue {
                 _juniper::InputValue::object(vec![
                     #(#to_inputs)*

juniper_codegen/src/derive_object.rs

@@ -111,6 +111,7 @@ pub fn impl_object(ast: &syn::DeriveInput) -> TokenStream {
 
     // Parse attributes.
     let ident = &ast.ident;
+    let generics = &ast.generics;
     let ident_name = ident.to_string();
     let attrs = ObjAttrs::from_input(ast);
     let name = attrs.name.unwrap_or(ast.ident.to_string());
@@ -170,7 +171,7 @@ pub fn impl_object(ast: &syn::DeriveInput) -> TokenStream {
     }
 
     let toks = quote! {
-        impl ::juniper::GraphQLType for #ident {
+        impl #generics ::juniper::GraphQLType for #ident #generics {
             type Context = ();
             type TypeInfo = ();
 

juniper_tests/src/codegen/derive_input_object.rs

@@ -1,8 +1,7 @@
 #[cfg(test)]
 use fnv::FnvHashMap;
 
-#[cfg(test)]
-use juniper::{self, FromInputValue, GraphQLType, InputValue};
+use juniper::{self, FromInputValue, GraphQLType, InputValue, ToInputValue};
 
 #[derive(GraphQLInputObject, Debug, PartialEq)]
 #[graphql(name = "MyInput", description = "input descr")]
@@ -42,6 +41,46 @@ struct OverrideDocComment {
     regular_field: bool,
 }
 
+#[derive(Debug, PartialEq)]
+struct Fake;
+
+impl<'a> FromInputValue for &'a Fake {
+    fn from_input_value(_v: &InputValue) -> Option<&'a Fake> {
+        None
+    }
+}
+
+impl<'a> ToInputValue for &'a Fake {
+    fn to_input_value(&self) -> InputValue {
+        InputValue::string("this is fake".to_string())
+    }
+}
+
+impl<'a> GraphQLType for &'a Fake {
+    type Context = ();
+    type TypeInfo = ();
+
+    fn name(_: &()) -> Option<&'static str> {
+        None
+    }
+    fn meta<'r>(_: &(), registry: &mut juniper::Registry<'r>) -> juniper::meta::MetaType<'r> {
+        let meta = registry.build_enum_type::<&'a Fake>(
+            &(),
+            &[juniper::meta::EnumValue {
+                name: "fake".to_string(),
+                description: None,
+                deprecation_reason: None,
+            }],
+        );
+        meta.into_meta()
+    }
+}
+
+#[derive(GraphQLInputObject, Debug, PartialEq)]
+struct WithLifetime<'a> {
+    regular_field: &'a Fake,
+}
+
 #[test]
 fn test_derived_input_object() {
     assert_eq!(Input::name(&()), Some("MyInput"));

juniper_tests/src/codegen/derive_object.rs

@@ -48,6 +48,11 @@ struct OverrideDocComment {
     regular_field: bool,
 }
 
+#[derive(GraphQLObject, Debug, PartialEq)]
+struct WithLifetime<'a> {
+    regular_field: &'a i32,
+}
+
 #[derive(GraphQLObject, Debug, PartialEq)]
 struct SkippedFieldObj {
     regular_field: bool,