Fix resolving generic properties

Author: varahash

src/main/kotlin/com/coxautodev/graphql/tools/MethodFieldResolver.kt

@@ -103,7 +103,7 @@ internal class MethodFieldResolver(field: FieldDefinition, search: FieldResolver
 
     override fun scanForMatches(): List<TypeClassMatcher.PotentialMatch> {
         val batched = isBatched(method, search)
-        val unwrappedGenericType = genericType.unwrapGenericType(method.kotlinFunction?.returnType?.javaType ?: method.returnType)
+        val unwrappedGenericType = genericType.unwrapGenericType(method.kotlinFunction?.returnType?.javaType ?: method.genericReturnType)
         val returnValueMatch = TypeClassMatcher.PotentialMatch.returnValue(field.type, unwrappedGenericType, genericType, SchemaClassScanner.ReturnValueReference(method), batched)
 
         return field.inputValueDefinitions.mapIndexed { i, inputDefinition ->

src/test/groovy/com/coxautodev/graphql/tools/EndToEndSpec.groovy

@@ -495,6 +495,24 @@ class EndToEndSpec extends Specification {
             ]
     }
 
+    def "generated schema supports generic properties"() {
+        when:
+        def data = Utils.assertNoGraphQlErrors(gql) {
+                '''
+                {
+                    itemWithGenericProperties {
+                        keys
+                    }
+                }
+                '''
+        }
+
+        then:
+        data.itemWithGenericProperties == [
+                keys: ["A", "B"]
+        ]
+    }
+
     def "generated schema supports batched datafetchers"() {
         when:
             def data = Utils.assertNoGraphQlErrors(batchedGql) {

src/test/kotlin/com/coxautodev/graphql/tools/EndToEndSpec.kt

@@ -50,6 +50,7 @@ type Query {
     itemsWithOptionalInputExplicit(itemsInput: ItemSearchInput): [Item!]
     enumInputType(type: Type!): Type!
     customScalarMapInputType(customScalarMap: customScalarMap): customScalarMap
+    itemWithGenericProperties: ItemWithGenericProperties!
 
     defaultArgument(arg: Boolean = true): Boolean!
     defaultEnumListArgument(types: [Type] = [TYPE_1]): [Type]
@@ -199,6 +200,10 @@ type Tag {
     id: Int!
     name: String!
 }
+
+type ItemWithGenericProperties {
+    keys: [String!]!
+}
 """
 
 
@@ -254,6 +259,7 @@ class Query: GraphQLQueryResolver, ListListResolver<String>() {
     fun itemsWithOptionalInputExplicit(input: Optional<ItemSearchInput>) = if(input.isPresent) items(input.get()) else items
     fun enumInputType(type: Type) = type
     fun customScalarMapInputType(customScalarMap: Map<String, Any>) = customScalarMap
+    fun itemWithGenericProperties() = ItemWithGenericProperties(listOf("A", "B"))
 
     fun defaultArgument(arg: Boolean) = arg
     fun defaultEnumListArgument(types: List<Type>) = types
@@ -355,6 +361,7 @@ data class NewItemInput(val name: String, val type: Type)
 data class ComplexNullable(val first: String, val second: String, val third: String)
 data class ComplexInputType(val first: String, val second: List<List<ComplexInputTypeTwo>?>?)
 data class ComplexInputTypeTwo(val first: String)
+data class ItemWithGenericProperties(val keys: List<String>)
 
 val customScalarId = GraphQLScalarType("ID", "Overrides built-in ID", object : Coercing<UUID, String> {
     override fun serialize(input: Any): String? = when (input) {