`KotlinBeanInfoFactory` throws an exception when creating bean info for enums

[klaasdellschaft]

Hi,

when upgrading my project from Spring Boot 3.1.x to 3.2.0 (and thus from Spring Beans 6.0.x / Spring Data Commons 3.1.x), I get an exception during runtime when the KotlinBeanInfoFactory tries to return the bean info for a Kotlin enum type. The following code can be used for reproducing the problem:

enum class SomeEnum(val someProperty: String) {
	VALUE_1("someValue1"),
	VALUE_2("someValue2")
}

@Test
fun determinesEnumProperties() {
    val pds = org.springframework.beans.BeanUtils.getPropertyDescriptors(SomeEnum::class.java)
    assertThat(pds).extracting("name").contains("someProperty")
}

This produces the following exception:

kotlin.reflect.jvm.internal.KotlinReflectionInternalError: No accessor found for property val entries: kotlin.enums.EnumEntries<org.springframework.data.util.KotlinBeanInfoFactoryUnitTests.SomeEnum>

	at kotlin.reflect.jvm.internal.KPropertyImplKt.computeCallerForAccessor(KPropertyImpl.kt:314)
	at kotlin.reflect.jvm.internal.KPropertyImplKt.access$computeCallerForAccessor(KPropertyImpl.kt:1)
	at kotlin.reflect.jvm.internal.KPropertyImpl$Getter$caller$2.invoke(KPropertyImpl.kt:180)
	at kotlin.reflect.jvm.internal.KPropertyImpl$Getter$caller$2.invoke(KPropertyImpl.kt:179)
	at kotlin.SafePublicationLazyImpl.getValue(LazyJVM.kt:107)
	at kotlin.reflect.jvm.internal.KPropertyImpl$Getter.getCaller(KPropertyImpl.kt:179)
	at kotlin.reflect.jvm.ReflectJvmMapping.getJavaMethod(ReflectJvmMapping.kt:64)
	at kotlin.reflect.jvm.ReflectJvmMapping.getJavaGetter(ReflectJvmMapping.kt:49)
	at org.springframework.data.util.KotlinBeanInfoFactory.getBeanInfo(KotlinBeanInfoFactory.java:67)
	at org.springframework.beans.CachedIntrospectionResults.getBeanInfo(CachedIntrospectionResults.java:222)
	at org.springframework.beans.CachedIntrospectionResults.<init>(CachedIntrospectionResults.java:248)
	at org.springframework.beans.CachedIntrospectionResults.forClass(CachedIntrospectionResults.java:157)
	at org.springframework.beans.BeanUtils.getPropertyDescriptors(BeanUtils.java:490)

This problem is potentially similar to #2964

In the above test, I'm not sure which other properties should be asserted (in addition to someProperty). Checking with previous behavior in Spring Beans 6.0.x (from which BeanUtils is coming from) / Spring Data Commons 3.1.x, the following properties had previously been detected for the SomeEnum class: class, declaringClass, entries, someProperty, name, ordinal.

[mp911de]

It makes sense for us to backoff for enums. We do not want to determine properties for enums as we treat enums as values. class, declaringClass, entries and other properties are determined by the simple bean info factory.

[mp911de]

That's fixed now. Do you want to give the latest 3.2.1 snapshots (3.2.1-SNAPSHOT) a try?

[klaasdellschaft]

Hi @mp911de thanks for the quick fix of the problem. I gave 3.2.1-SNAPSHOT a try in my application. It was successful, so I would consider it fixed for now.

[mp911de]

Thanks for checking out the fix. It's going to be available with the next service release mid-December, see https://calendar.spring.io/.