Absent parameters cause NPE in ClassGeneratingEntityInstantiator [DATACMNS-1200]

[spring-projects-issues]

Mark Paluch opened DATACMNS-1200 and commented

Consider following domain objects:

class JavaClass {

	public int param1;

	public ObjectCtor1ParamInt(int param1) {
		this.param1 = param1;
	}
}

data class KotlinClass(val state: Boolean = true)

Instantiating any of these (Java classes with primitives, Kotlin classes with primitives) causes a NullPointerException:

java.lang.NullPointerException
	at org.springframework.data.convert.KotlinClassGeneratingEntityInstantiatorUnitTests$WithDefaultBoolean_Instantiator_480p78.newInstance(Unknown Source)
	at org.springframework.data.convert.KotlinClassGeneratingEntityInstantiator$DefaultingKotlinClassInstantiatorAdapter.createInstance(KotlinClassGeneratingEntityInstantiator.java:240)
	at org.springframework.data.convert.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:85)
	at org.springframework.data.convert.KotlinClassGeneratingEntityInstantiatorUnitTests.should create instance and fill in default for primitive boolean(KotlinClassGeneratingEntityInstantiatorUnitTests.kt:92)

The NPE is caused from casting null into a primitive. In any case, it's hard to investigate why the issue happens. Ideally, for Java classes, we throw an IAE containing the property name that is null. For Kotlin, we should fall back to a primitive default value and let Kotlin's defaulting set the appropriate value if the parameter has a default.

---

Affects: 2.0 GA (Kay)

Reference URL: https://github.com/tiarebalbi/spring-data-kotlin-nullable-query/tree/4be37d33caf400f5475c55e8818b90d7eaa583f9

Referenced from: pull request #255

Backported to: 2.0.1 (Kay SR1)