feat: try isAssignableFrom instead of DFS isSubclassOf (#2114)

### 📝 Description
cherry pick #2109 for
7.x.x branch

### 🔗 Related Issues
#1570

Co-authored-by: Samuel Vazquez <sam_2f@hotmail.com>

Author: tapaderster

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/internal/extensions/kClassExtensions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 Expedia, Inc
+ * Copyright 2025 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,7 +29,6 @@ import kotlin.reflect.KVisibility
 import kotlin.reflect.full.declaredMemberFunctions
 import kotlin.reflect.full.declaredMemberProperties
 import kotlin.reflect.full.findParameterByName
-import kotlin.reflect.full.isSubclassOf
 import kotlin.reflect.full.memberFunctions
 import kotlin.reflect.full.memberProperties
 import kotlin.reflect.full.primaryConstructor
@@ -67,7 +66,7 @@ private fun KClass<*>.isDeclaredUnion() = this.isInterface() && this.declaredMem
 internal fun KClass<*>.isAnnotationUnion(fieldAnnotations: List<Annotation>): Boolean = (this.isInstance(Any::class) || this.isAnnotation()) &&
     fieldAnnotations.getUnionAnnotation() != null
 
-internal fun KClass<*>.isAnnotation(): Boolean = this.isSubclassOf(Annotation::class)
+internal fun KClass<*>.isAnnotation(): Boolean = Annotation::class.java.isAssignableFrom(this.java)
 
 /**
  * Do not add interfaces as additional types if it expects all the types
@@ -78,9 +77,9 @@ internal fun KClass<*>.isAnnotation(): Boolean = this.isSubclassOf(Annotation::c
  */
 internal fun KClass<*>.isValidAdditionalType(inputType: Boolean): Boolean = !(inputType && this.isInterface()) && !this.isGraphQLIgnored()
 
-internal fun KClass<*>.isEnum(): Boolean = this.isSubclassOf(Enum::class)
+internal fun KClass<*>.isEnum(): Boolean = Enum::class.java.isAssignableFrom(this.java)
 
-internal fun KClass<*>.isListType(isDirective: Boolean = false): Boolean = this.isSubclassOf(List::class) || (isDirective && this.java.isArray)
+internal fun KClass<*>.isListType(isDirective: Boolean = false): Boolean = List::class.java.isAssignableFrom(this.java) || (isDirective && this.java.isArray)
 
 @Throws(CouldNotGetNameOfKClassException::class)
 internal fun KClass<*>.getSimpleName(isInputClass: Boolean = false): String {

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/internal/extensions/kParameterExtensions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 Expedia, Inc
+ * Copyright 2025 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/internal/extensions/kTypeExtensions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 Expedia, Inc
+ * Copyright 2025 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,15 +20,14 @@ import com.expediagroup.graphql.generator.exceptions.InvalidWrappedTypeException
 import com.expediagroup.graphql.generator.execution.OptionalInput
 import kotlin.reflect.KClass
 import kotlin.reflect.KType
-import kotlin.reflect.full.isSubclassOf
 import kotlin.reflect.full.withNullability
 import kotlin.reflect.jvm.jvmErasure
 
 internal fun KType.getKClass() = this.jvmErasure
 
 internal fun KType.getJavaClass(): Class<*> = this.getKClass().java
 
-internal fun KType.isSubclassOf(kClass: KClass<*>) = this.getKClass().isSubclassOf(kClass)
+internal fun KType.isSubclassOf(kClass: KClass<*>) = kClass.java.isAssignableFrom(this.getJavaClass())
 
 internal fun KType.isList() = this.isSubclassOf(List::class)
 

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/internal/state/TypesCache.kt

@@ -35,7 +35,6 @@ import java.io.Closeable
 import kotlin.reflect.KClass
 import kotlin.reflect.KType
 import kotlin.reflect.full.createType
-import kotlin.reflect.full.isSubclassOf
 import kotlin.reflect.full.starProjectedType
 
 internal class TypesCache(private val supportedPackages: List<String>) : Closeable {
@@ -126,7 +125,7 @@ internal class TypesCache(private val supportedPackages: List<String>) : Closeab
 
             when {
                 kClass.isListType(cacheKey.isDirective) -> null
-                kClass.isSubclassOf(Enum::class) -> kClass.getSimpleName()
+                Enum::class.java.isAssignableFrom(kClass.java) -> kClass.getSimpleName()
                 isTypeNotSupported(type) -> throw TypeNotSupportedException(type, supportedPackages)
                 else -> type.getSimpleName(cacheKey.inputType)
             }

generator/graphql-kotlin-schema-generator/src/test/kotlin/com/expediagroup/graphql/generator/internal/extensions/KClassExtensionsTest.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 Expedia, Inc
+ * Copyright 2025 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

generator/graphql-kotlin-schema-generator/src/test/kotlin/com/expediagroup/graphql/generator/internal/extensions/KParameterExtensionsKtTest.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 Expedia, Inc
+ * Copyright 2015 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

generator/graphql-kotlin-schema-generator/src/test/kotlin/com/expediagroup/graphql/generator/internal/extensions/KTypeExtensionsKtTest.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 Expedia, Inc
+ * Copyright 2025 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -46,6 +46,8 @@ class KTypeExtensionsKtTest {
 
     class SimpleClass(val id: String) : SimpleInterface
 
+    enum class SimpleEnum { ONE, TWO, THREE }
+
     @Test
     fun getTypeOfFirstArgument() {
         assertEquals(String::class.starProjectedType, MyClass::listFun.findParameterByName("list")?.type?.getTypeOfFirstArgument())
@@ -92,6 +94,7 @@ class KTypeExtensionsKtTest {
     fun isSubclassOf() {
         assertTrue(MyClass::class.starProjectedType.isSubclassOf(MyClass::class))
         assertTrue(SimpleClass::class.starProjectedType.isSubclassOf(SimpleInterface::class))
+        assertTrue(SimpleEnum::class.starProjectedType.isSubclassOf(Enum::class))
         assertFalse(SimpleInterface::class.starProjectedType.isSubclassOf(SimpleClass::class))
         assertFalse(MyClass::class.starProjectedType.isSubclassOf(SimpleInterface::class))
     }