Handle object literal default values on custom scalar input fields

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/java/DataTypeGenerator.kt

@@ -285,12 +285,25 @@ class InputTypeGenerator internal constructor(
 
             is ObjectValue -> {
                 val inputObjectDefinition =
-                    inputTypeDefinitions.first {
+                    inputTypeDefinitions.firstOrNull {
                         val expectedCanonicalClassName =
                             config.typeMapping[it.name] ?: "${config.packageNameTypes}.${it.name}"
                         expectedCanonicalClassName == type.className.canonicalName()
                     }
-                if (value.objectFields.isEmpty()) {
+                if (inputObjectDefinition == null) {
+                    val canonical = type.className.canonicalName()
+                    if (canonical == "java.util.Map" || canonical == "java.util.HashMap") {
+                        if (value.objectFields.isEmpty()) {
+                            CodeBlock.of("\$T.emptyMap()", Collections::class.java)
+                        } else {
+                            null
+                        }
+                    } else if (value.objectFields.isEmpty()) {
+                        CodeBlock.of("new \$T()", type)
+                    } else {
+                        null
+                    }
+                } else if (value.objectFields.isEmpty()) {
                     CodeBlock.of("new \$T()", type)
                 } else {
                     CodeBlock.of(
@@ -379,7 +392,12 @@ class InputTypeGenerator internal constructor(
         get() =
             when (this) {
                 is ClassName -> this
-                is ParameterizedTypeName -> typeArguments().first().className
+                is ParameterizedTypeName ->
+                    if (rawType().canonicalName() == "java.util.List") {
+                        typeArguments().first().className
+                    } else {
+                        rawType()
+                    }
                 else -> throw UnsupportedOperationException("Unknown type: ${this.javaClass}")
             }
 }

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/shared/GenerateKotlinCode.kt

@@ -61,12 +61,40 @@ fun generateKotlinCode(
 
             is ObjectValue -> {
                 val inputObjectDefinition =
-                    inputTypeDefinitions.first {
+                    inputTypeDefinitions.firstOrNull {
                         val expectedCanonicalClassName =
                             config.typeMapping[it.name] ?: "${config.packageNameTypes}.${it.name}"
                         expectedCanonicalClassName == type.className.canonicalName
                     }
 
+                if (inputObjectDefinition == null) {
+                    val canonical = type.className.canonicalName
+                    if (canonical == "kotlin.collections.Map" || canonical == "java.util.Map") {
+                        if (value.objectFields.isEmpty()) {
+                            CodeBlock.of("emptyMap()")
+                        } else {
+                            CodeBlock.of(
+                                "mapOf(%L)",
+                                value.objectFields.joinToString { objectProperty ->
+                                    "\"${objectProperty.name}\" to ${
+                                        generateKotlinCode(
+                                            objectProperty.value,
+                                            type,
+                                            inputTypeDefinitions,
+                                            config,
+                                            typeUtils,
+                                        )
+                                    }"
+                                },
+                            )
+                        }
+                    } else if (value.objectFields.isEmpty()) {
+                        CodeBlock.of("%T()", type)
+                    } else {
+                        CodeBlock.of("null")
+                    }
+                } else {
+
                 CodeBlock.of(
                     type.className.canonicalName + "(%L)",
                     value.objectFields.joinToString { objectProperty ->
@@ -85,6 +113,7 @@ fun generateKotlinCode(
                         }"
                     },
                 )
+                }
             }
 
             is NullValue -> CodeBlock.of("null")
@@ -147,6 +176,11 @@ private val TypeName.className: ClassName
     get() =
         when (this) {
             is ClassName -> this
-            is ParameterizedTypeName -> typeArguments[0].className
+            is ParameterizedTypeName ->
+                if (rawType.canonicalName == "kotlin.collections.List" || rawType.canonicalName == "java.util.List") {
+                    typeArguments[0].className
+                } else {
+                    rawType
+                }
             else -> TODO()
         }

graphql-dgs-codegen-core/src/test/kotlin/com/netflix/graphql/dgs/codegen/CodeGenTest.kt

@@ -2123,6 +2123,29 @@ class CodeGenTest {
         assertCompilesJava(codeGenResult)
     }
 
+    @Test
+    fun `Input field with scalar type and object literal default value does not fail in Java`() {
+        val schema =
+            """
+            scalar JSON
+            type Query {
+                search(filter: FilterInput): String
+            }
+            input FilterInput {
+                metadata: JSON = {}
+            }
+            """.trimIndent()
+        val codeGenResult =
+            CodeGen(
+                CodeGenConfig(
+                    schemas = setOf(schema),
+                    packageName = BASE_PACKAGE_NAME,
+                    typeMapping = mapOf("JSON" to "java.util.Map<String, Object>"),
+                ),
+            ).generate()
+        assertCompilesJava(codeGenResult)
+    }
+
     @ParameterizedTest
     @ValueSource(booleans = [true, false])
     fun generateInputWithDefaultValueForEnum(trackInputFieldSet: Boolean) {

graphql-dgs-codegen-core/src/test/kotlin/com/netflix/graphql/dgs/codegen/KotlinCodeGenTest.kt

@@ -75,6 +75,30 @@ class KotlinCodeGenTest {
         assertCompilesKotlin(codeGenResult)
     }
 
+    @Test
+    fun `Input field with scalar type and object literal default value does not fail in Kotlin`() {
+        val schema =
+            """
+            scalar JSON
+            type Query {
+                search(filter: FilterInput): String
+            }
+            input FilterInput {
+                metadata: JSON = {}
+            }
+            """.trimIndent()
+        val codeGenResult =
+            CodeGen(
+                CodeGenConfig(
+                    schemas = setOf(schema),
+                    packageName = BASE_PACKAGE_NAME,
+                    language = Language.KOTLIN,
+                    typeMapping = mapOf("JSON" to "Map<String, Any>"),
+                ),
+            ).generate()
+        assertCompilesKotlin(codeGenResult)
+    }
+
     @Test
     fun generateDataClassesOutsideMetaInf() {
         val schema =
@@ -5366,3 +5390,4 @@ It takes a title and such.
         }
         """.trimIndent()
 }
+

graphql-dgs-codegen-core/src/test/kotlin/com/netflix/graphql/dgs/codegen/TestUtils.kt

@@ -113,7 +113,7 @@ fun classpath(): String =
         .split(System.getProperty("path.separator"))
         .filter {
             File(it).exists() && File(it).canRead()
-        }.joinToString(":")
+        }.joinToString(File.pathSeparator)
 
 fun codegenTestClassLoader(
     compilation: Compilation,
@@ -202,3 +202,4 @@ fun KAnnotationSpec.canonicalName() = (typeName as KClassName).canonicalName
 const val BASE_PACKAGE_NAME = "com.netflix.graphql.dgs.codegen.tests.generated"
 const val TYPES_PACKAGE_NAME = "$BASE_PACKAGE_NAME.types"
 const val DATA_FETCHER_PACKAGE_NAME = "$BASE_PACKAGE_NAME.datafetchers"
+