Avoid duplicate definitions of the same types when using connections

Author: Thomas Draier

src/main/java/graphql/annotations/GraphQLAnnotations.java

@@ -588,12 +588,21 @@ private GraphQLOutputType internalGetGraphQLConnection(AccessibleObject field, G
         assert wrappedType instanceof GraphQLObjectType;
         String connectionName = field.getAnnotation(GraphQLConnection.class).name();
         connectionName = connectionName.isEmpty() ? wrappedType.getName() : connectionName;
-        GraphQLObjectType edgeType = relay.edgeType(connectionName, (GraphQLOutputType) wrappedType, null, Collections.<GraphQLFieldDefinition>emptyList());
-        type = relay.connectionType(connectionName, edgeType, Collections.emptyList());
+        GraphQLObjectType edgeType = ensureTypeUniqueness(relay.edgeType(connectionName, (GraphQLOutputType) wrappedType, null, Collections.<GraphQLFieldDefinition>emptyList()));
+        type = ensureTypeUniqueness(relay.connectionType(connectionName, edgeType, Collections.emptyList()));
         builder.argument(relay.getConnectionFieldArguments());
         return type;
     }
 
+    private GraphQLObjectType ensureTypeUniqueness(GraphQLObjectType type) {
+        if (typeRegistry.containsKey(type.getName())) {
+            type = (GraphQLObjectType) typeRegistry.get(type.getName());
+        } else {
+            typeRegistry.put(type.getName(), type);
+        }
+        return type;
+    }
+
     private boolean isConnection(AccessibleObject obj, GraphQLOutputType type) {
         if (type instanceof GraphQLNonNull) {
             type = (GraphQLOutputType) ((GraphQLNonNull) type).getWrappedType();

src/test/java/graphql/annotations/GraphQLConnectionTest.java

@@ -26,6 +26,7 @@
 import org.testng.annotations.Test;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Stream;
@@ -55,6 +56,14 @@ public Obj(String id, String val) {
         }
     }
 
+    public static class DuplicateTest {
+        @GraphQLField
+        public TestListField field1;
+
+        @GraphQLField
+        public TestListField2 field2;
+    }
+
     public static class TestListField {
         @GraphQLField
         @GraphQLConnection
@@ -65,6 +74,16 @@ public TestListField(List<Obj> objs) {
         }
     }
 
+    public static class TestListField2 {
+        @GraphQLField
+        @GraphQLConnection
+        public List<Obj> objs;
+
+        public TestListField2(List<Obj> objs) {
+            this.objs = objs;
+        }
+    }
+
     @Test
     public void fieldList() {
         GraphQLObjectType object = GraphQLAnnotations.object(TestListField.class);
@@ -270,4 +289,11 @@ public void customConnection() {
         assertEquals(edges.size(), 0);
     }
 
+    @Test
+    public void duplicateConnection() {
+        GraphQLObjectType object = GraphQLAnnotations.object(DuplicateTest.class);
+        GraphQLSchema schema = newSchema().query(object).build();
+        System.out.println("ok");
+    }
+
 }