[GROOVY-9916] IllegalArgumentException when set null to a boolean field into a closure

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.5.13, 3.0.7
• Fix Version/s: 3.0.8, 4.0.0-alpha-3
• Assignee: Eric Milles
• Reporter: Eric Vernier
• Created: 27/Jan/21 17:56
• Updated: 02/May/21 09:16
• Resolved: 02/Mar/21 15:06

Description

The following exception has been thrown by an application in production:

Caused by: java.lang.IllegalArgumentException: Can not set boolean field c.c.a.a.b.t.b.save.RestoreDataMssqlTask.schemaExistInBackup to null value
	at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167)
	at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:171)
	at sun.reflect.UnsafeBooleanFieldAccessorImpl.set(UnsafeBooleanFieldAccessorImpl.java:80)
	at java.lang.reflect.Field.set(Field.java:764)
	at org.codehaus.groovy.reflection.CachedField.setProperty(CachedField.java:76)
	at groovy.lang.MetaClassImpl.setProperty(MetaClassImpl.java:2718)
	at groovy.lang.MetaClassImpl.setProperty(MetaClassImpl.java:3809)
	at c.c.a.a.b.t.b.save.AbstractRestoreTask.setProperty(AbstractRestoreTask.groovy)
	at org.codehaus.groovy.runtime.InvokerHelper.setProperty(InvokerHelper.java:213)
	at groovy.lang.Closure.setPropertyTryThese(Closure.java:370)
	at groovy.lang.Closure.setPropertyOwnerFirst(Closure.java:364)
	at groovy.lang.Closure.setProperty(Closure.java:353)
	at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.setGroovyObjectProperty(ScriptBytecodeAdapter.java:544)
	at c.c.a.a.b.t.b.save.RestoreDataMssqlTask$_execImportDatasource_closure1.doCall(RestoreDataMssqlTask.groovy:86)

I think the following test class reproduces the problem :

class Test {

	private boolean b
	
	static final void main(String... args) {
		new Test().f()
	}
	
	def f() {
		println('set boolean to null')
		b = null
		def closure = { 
			println('set boolean to null inside a closure')
			b = null
		}
		closure()
	}	
}

The conditions are 1) affect null to a primitive boolean variable, 2) the variable must be an instance field, 3) the affectation must be executed in a closure

With Groovy 2.5.5 no exception.

$ groovy -version
Groovy Version: 2.5.5 JVM: 1.8.0_265 Vendor: AdoptOpenJDK OS: Windows 10

$ groovy Test
set boolean to null
set boolean to null inside a closure

But with groovy 2.5.13 or the last stable version 3.0.7 the second affectation failed :

$ groovy -version
Groovy Version: 3.0.7 JVM: 1.8.0_265 Vendor: AdoptOpenJDK OS: Windows 10

$ groovy Test
set boolean to null
set boolean to null inside a closure
Caught: java.lang.IllegalArgumentException: Can not set boolean field Test.b to null value
java.lang.IllegalArgumentException: Can not set boolean field Test.b to null value
        at Test$_f_closure1.doCall(Test.groovy:14)
        at Test$_f_closure1.doCall(Test.groovy)
        at Test.f(Test.groovy:16)
        at Test$f.call(Unknown Source)
        at Test.main(Test.groovy:6)

In org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation the method castToBoolean() takes care of the null value in accordance with the Groovy truth:

public static boolean castToBoolean(Object object) {
        // null is always false
        if (object == null) {
            return false;
        }

but the method castToBoolean() is obviously never called by castToType() when the value is null because the first line of castToType is :

if (object == null) return null;

How can I deal with this behaviour? I guess I must stuck ith the old 2.5.5 ?