Allow updating custom additional types (ExpediaGroup#593)

* Allow updating custom additional types

As dicussed in other PRs ExpediaGroup#587 and ExpediaGroup#585 we can allow developers to have more customization of the schema by allowing them to add additional types of their own without having to add it to the schema directly. What they do with this feature will be up to them, but from a libray perspective it is not bad feature to support.

* Make function open

Author: smyrick

graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/SchemaGenerator.kt

@@ -82,5 +82,10 @@ open class SchemaGenerator(internal val config: SchemaGeneratorConfig) {
         }
     }
 
-    private fun generateAdditionalTypes(additionalTypes: Set<KType>): Set<GraphQLType> = additionalTypes.map { generateGraphQLType(this, it) }.toSet()
+    /**
+     * Generate the GraphQL type for all the `additionalTypes`. They are generated as non-inputs and not as IDs.
+     * If you need to provide more custom additional types that were not picked up from reflection of the schema objects,
+     * you can modify the set of `additionalTypes` before you call this method.
+     */
+    protected open fun generateAdditionalTypes(additionalTypes: Set<KType>): Set<GraphQLType> = additionalTypes.map { generateGraphQLType(this, it) }.toSet()
 }

graphql-kotlin-schema-generator/src/test/kotlin/com/expediagroup/graphql/generator/SchemaGeneratorTest.kt

@@ -17,8 +17,11 @@
 package com.expediagroup.graphql.generator
 
 import com.expediagroup.graphql.SchemaGeneratorConfig
+import com.expediagroup.graphql.extensions.deepName
 import org.junit.jupiter.api.Test
 import kotlin.reflect.KClass
+import kotlin.reflect.KType
+import kotlin.reflect.full.createType
 import kotlin.test.assertEquals
 
 class SchemaGeneratorTest {
@@ -38,8 +41,22 @@ class SchemaGeneratorTest {
         assertEquals(1, generator.additionalTypes.size)
     }
 
+    @Test
+    fun generateAdditionalTypes() {
+        val config = SchemaGeneratorConfig(listOf("com.expediagroup.graphql.generator"))
+        val generator = CustomSchemaGenerator(config)
+        val types = setOf(SomeObjectWithAnnotaiton::class.createType())
+
+        val result = generator.generateCustomAdditionalTypes(types)
+
+        assertEquals(1, result.size)
+        assertEquals("SomeObjectWithAnnotaiton!", result.first().deepName)
+    }
+
     class CustomSchemaGenerator(config: SchemaGeneratorConfig) : SchemaGenerator(config) {
         internal fun addTypes(annotation: KClass<*>) = addAdditionalTypesWithAnnotation(annotation)
+
+        internal fun generateCustomAdditionalTypes(types: Set<KType>) = generateAdditionalTypes(types)
     }
 
     annotation class MyCustomAnnotation