Fix nullable value class handling in CoroutinesUtils

Closes gh-36643
Signed-off-by: T45K <tasktas9@gmail.com>

Author: T45K

spring-core/src/main/java/org/springframework/core/CoroutinesUtils.java

@@ -129,7 +129,7 @@ public static Publisher<?> invokeSuspendingFunction(
 								Object arg = args[index];
 								if (!(parameter.isOptional() && arg == null)) {
 									KType type = parameter.getType();
-									if (!(type.isMarkedNullable() && arg == null) &&
+									if (!type.isMarkedNullable() &&
 											type.getClassifier() instanceof KClass<?> kClass &&
 											KotlinDetector.isInlineClass(JvmClassMappingKt.getJavaClass(kClass))) {
 										arg = box(kClass, arg);
@@ -161,7 +161,7 @@ public static Publisher<?> invokeSuspendingFunction(
 	private static Object box(KClass<?> kClass, @Nullable Object arg) {
 		KFunction<?> constructor = Objects.requireNonNull(KClasses.getPrimaryConstructor(kClass));
 		KType type = constructor.getParameters().get(0).getType();
-		if (!(type.isMarkedNullable() && arg == null) &&
+		if (!type.isMarkedNullable() &&
 				type.getClassifier() instanceof KClass<?> parameterClass &&
 				KotlinDetector.isInlineClass(JvmClassMappingKt.getJavaClass(parameterClass))) {
 			arg = box(parameterClass, arg);

spring-core/src/test/kotlin/org/springframework/core/CoroutinesUtilsTests.kt

@@ -237,6 +237,13 @@ class CoroutinesUtilsTests {
 		}
 	}
 
+	@Test
+	suspend fun invokeSuspendingFunctionWithNullableValueClassParameterWithNonnullObject() {
+		val method = CoroutinesUtilsTests::class.java.declaredMethods.first { it.name.startsWith("suspendingFunctionWithNullableValueClass") }
+		val mono = CoroutinesUtils.invokeSuspendingFunction(method, this, ValueClass("foo"), null) as Mono
+		Assertions.assertThat(mono.awaitSingleOrNull()).isEqualTo("foo")
+	}
+
 	@Test
 	fun invokeSuspendingFunctionWithNullableValueClassParameter() {
 		val method = CoroutinesUtilsTests::class.java.declaredMethods.first { it.name.startsWith("suspendingFunctionWithNullableValueClass") }