Expect only first parameter as List in Batched

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

@@ -91,12 +91,15 @@ internal class TypeClassMatcher(private val definitionsByName: Map<String, TypeD
     }
 
     private fun stripBatchedType(potentialMatch: PotentialMatch): PotentialMatch {
-        val realType = potentialMatch.generic.unwrapGenericType(potentialMatch.javaType)
-
-        if(realType is ParameterizedType && isListType(realType, potentialMatch)) {
-            return potentialMatch.copy(javaType = realType.actualTypeArguments.first(), batched = false)
+        if (potentialMatch.location != Location.RETURN_TYPE) {
+            return potentialMatch.copy(javaType = potentialMatch.javaType, batched = false)
         } else {
-            throw error(potentialMatch, "Method was marked as @Batched but ${potentialMatch.location.prettyName} was not a list!")
+            val realType = potentialMatch.generic.unwrapGenericType(potentialMatch.javaType)
+            if (realType is ParameterizedType && isListType(realType, potentialMatch)) {
+                return potentialMatch.copy(javaType = realType.actualTypeArguments.first(), batched = false)
+            } else {
+                throw error(potentialMatch, "Method was marked as @Batched but ${potentialMatch.location.prettyName} was not a list!")
+            }
         }
     }
 

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

@@ -375,4 +375,22 @@ class EndToEndSpec extends Specification {
         then:
             data.allBaseItems.collect { it.name } == ['item1', 'item2']
     }
+
+    def "generated schema supports batched datafetchers with params"() {
+        when:
+        def data = Utils.assertNoGraphQlErrors(gql) {
+            '''
+                {
+                    allBaseItems {
+                        tags: batchedWithParamsTags(names: ["item2-tag1"]) {
+                            name
+                        }
+                    }
+                }
+                '''
+        }
+
+        then:
+        data.allBaseItems.collect { it.tags.collect { it.name } } == [[], ['item2-tag1']]
+    }
 }

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

@@ -109,6 +109,7 @@ type Item implements ItemInterface {
     uuid: UUID!
     tags(names: [String!]): [Tag!]
     batchedName: String!
+    batchedWithParamsTags(names: [String!]): [Tag!]
 }
 
 type OtherItem implements ItemInterface {
@@ -214,6 +215,9 @@ class ItemResolver : GraphQLResolver<Item> {
 
     @Batched
     fun batchedName(items: List<Item>) = items.map { it.name }
+
+    @Batched
+    fun batchedWithParamsTags(items: List<Item>, names: List<String>?): List<List<Tag>> = items.map{ it.tags.filter { names?.contains(it.name) ?: true } }
 }
 
 interface ItemInterface {