From b484a6104d70a2c861d5e39f82068f9375481729 Mon Sep 17 00:00:00 2001
From: Sunli <scott_s829@163.com>
Date: Wed, 5 Jan 2022 11:52:02 +0800
Subject: [PATCH] Fix the generic `SimpleObject` can't define the lifetimes.
 #774

---
 derive/src/simple_object.rs | 38 ++++++++++++++++++---
 tests/generic_types.rs      | 68 +++++++++++++++++++++++++++++++++++++
 2 files changed, 101 insertions(+), 5 deletions(-)

diff --git a/derive/src/simple_object.rs b/derive/src/simple_object.rs
index 15f80f85..5534149a 100644
--- a/derive/src/simple_object.rs
+++ b/derive/src/simple_object.rs
@@ -3,7 +3,8 @@ use proc_macro::TokenStream;
 use quote::quote;
 use std::str::FromStr;
 use syn::ext::IdentExt;
-use syn::{Error, Ident, Path, Type};
+use syn::visit::Visit;
+use syn::{Error, Ident, LifetimeDef, Path, Type};
 
 use crate::args::{self, RenameRuleExt, RenameTarget, SimpleObjectField};
 use crate::utils::{
@@ -320,6 +321,33 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
     } else {
         let mut code = Vec::new();
 
+        #[derive(Default)]
+        struct GetLifetimes<'a> {
+            lifetimes: Vec<&'a LifetimeDef>,
+        }
+
+        impl<'a> Visit<'a> for GetLifetimes<'a> {
+            fn visit_lifetime_def(&mut self, i: &'a LifetimeDef) {
+                self.lifetimes.push(i);
+            }
+        }
+
+        let mut visitor = GetLifetimes::default();
+        visitor.visit_generics(&object_args.generics);
+        let lifetimes = visitor.lifetimes;
+
+        let def_lifetimes = if !lifetimes.is_empty() {
+            Some(quote!(<#(#lifetimes),*>))
+        } else {
+            None
+        };
+
+        let type_lifetimes = if !lifetimes.is_empty() {
+            Some(quote!(#(#lifetimes,)*))
+        } else {
+            None
+        };
+
         code.push(quote! {
             impl #impl_generics #ident #ty_generics #where_clause {
                 #(#getters)*
@@ -357,12 +385,12 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
         for concrete in &object_args.concretes {
             let gql_typename = &concrete.name;
             let params = &concrete.params.0;
-            let concrete_type = quote! { #ident<#(#params),*> };
+            let concrete_type = quote! { #ident<#type_lifetimes #(#params),*> };
 
             let expanded = quote! {
                 #[allow(clippy::all, clippy::pedantic)]
                 #[#crate_name::async_trait::async_trait]
-                impl #crate_name::resolver_utils::ContainerType for #concrete_type {
+                impl #def_lifetimes #crate_name::resolver_utils::ContainerType for #concrete_type {
                     async fn resolve_field(&self, ctx: &#crate_name::Context<'_>) -> #crate_name::ServerResult<::std::option::Option<#crate_name::Value>> {
                         #complex_resolver
                         self.__internal_resolve_field(ctx).await
@@ -371,7 +399,7 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
 
                 #[allow(clippy::all, clippy::pedantic)]
                 #[#crate_name::async_trait::async_trait]
-                impl #crate_name::OutputType for #concrete_type {
+                impl #def_lifetimes #crate_name::OutputType for #concrete_type {
                     fn type_name() -> ::std::borrow::Cow<'static, ::std::primitive::str> {
                         ::std::borrow::Cow::Borrowed(#gql_typename)
                     }
@@ -387,7 +415,7 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
                     }
                 }
 
-                impl #crate_name::ObjectType for #concrete_type {}
+                impl #def_lifetimes #crate_name::ObjectType for #concrete_type {}
             };
             code.push(expanded);
         }
diff --git a/tests/generic_types.rs b/tests/generic_types.rs
index 6887d872..30f95253 100644
--- a/tests/generic_types.rs
+++ b/tests/generic_types.rs
@@ -348,3 +348,71 @@ pub async fn test_concrete_object() {
         })
     );
 }
+
+#[tokio::test]
+pub async fn test_concrete_object_with_lifetime() {
+    #[derive(SimpleObject)]
+    #[graphql(concrete(name = "Bar0", params(i32)))]
+    #[graphql(concrete(name = "Bar1", params(i64)))]
+    struct Foo<'a, T>
+    where
+        T: Sync + OutputType + 'a,
+    {
+        data: &'a T,
+    }
+
+    struct Query {
+        value1: i32,
+        value2: i64,
+    }
+
+    #[Object]
+    impl Query {
+        async fn a(&self) -> Foo<'_, i32> {
+            Foo { data: &self.value1 }
+        }
+
+        async fn b(&self) -> Foo<'_, i64> {
+            Foo { data: &self.value2 }
+        }
+
+        async fn static_a(&self) -> Foo<'static, i32> {
+            Foo { data: &100 }
+        }
+
+        async fn static_b(&self) -> Foo<'static, i32> {
+            Foo { data: &200 }
+        }
+    }
+
+    let schema = Schema::new(
+        Query {
+            value1: 88,
+            value2: 99,
+        },
+        EmptyMutation,
+        EmptySubscription,
+    );
+
+    assert_eq!(
+        schema
+            .execute(
+                r#"{ 
+                a { data } 
+                b { data }
+                staticA { data }
+                staticB { data }
+            }"#
+            )
+            .await
+            .into_result()
+            .unwrap()
+            .data,
+        value!({
+            "a": { "data": 88 },
+            "b": { "data": 99 },
+            "staticA": { "data": 100 },
+            "staticB": { "data": 200 },
+        })
+    );
+}