From 65e88b994ea9d8f1458b240f6bd8500698ccb954 Mon Sep 17 00:00:00 2001
From: Felix Sun <sunfmin@gmail.com>
Date: Fri, 24 May 2019 16:36:09 +0800
Subject: [PATCH] #726: Mark field as resolver with graphql directives

---
 README.md        | 18 +++++++++++++++---
 codegen/field.go |  3 +++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index c29a7d2f1a..70dacb018d 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@
 
  - **Schema first** — Define your API using the GraphQL [Schema Definition Language](http://graphql.org/learn/schema/).
  - **Type safe** — You should never see `map[string]interface{}` here.
- - **Codegen** — Let us generate the boring bits, so you can build your app quickly. 
+ - **Codegen** — Let us generate the boring bits, so you can build your app quickly.
 
 [Feature Comparison](https://gqlgen.com/feature-comparison/)
 
@@ -36,7 +36,7 @@ type User {
     friends: [User!]!
 }
 ```
-You need to tell gqlgen that we should only fetch friends if the user requested it. There are two ways to do this.
+You need to tell gqlgen that we should only fetch friends if the user requested it. There are three ways to do this.
 
 1. Write the model yourself and leave off friends.
 
@@ -65,13 +65,25 @@ models:
         resolver: true # force a resolver to be generated
 ```
 
+3. Use graphql directives @resolver on field to mark the field as requiring a resolver explicitly
+
+```graphql
+directive @resolver on FIELD_DEFINITION
+
+type User {
+    id: ID!
+    name: String!
+    friends: [User!]! @resolver # force a resolver to be generated
+}
+```
+
 After doing either of the above and running generate we will need to provide a resolver for friends:
 ```go
 func (r *userResolver) User(ctx context.Context, obj *User) ([]*User, error) {
     // select * from user where friendid = obj.ID
     return friends,  nil
 }
-``` 
+```
 
 ### IDs are strings but I like ints, why cant I have ints?
 
diff --git a/codegen/field.go b/codegen/field.go
index f5f7b22139..7e525380e6 100644
--- a/codegen/field.go
+++ b/codegen/field.go
@@ -98,6 +98,9 @@ func (b *builder) bindField(obj *Object, f *Field) error {
 	case obj.Root:
 		f.IsResolver = true
 		return nil
+	case f.FieldDefinition.Directives.ForName("resolver") != nil:
+		f.IsResolver = true
+		return nil
 	case b.Config.Models[obj.Name].Fields[f.Name].Resolver:
 		f.IsResolver = true
 		return nil