Using Groovy Trait in Grails Test Fails

Question

How can I implement Groovy's new traits in my Grails Spock tests? Every time I try, I get a stacktrace that looks like this. Is there some limitation of Groovy trails that I might not be aware of?

JDK Version:

java version "1.7.0_65"
OpenJDK Runtime Environment (IcedTea 2.5.3) (7u71-2.5.3-0ubuntu0.14.04.1)
OpenJDK 64-Bit Server VM (build 24.65-b04, mixed mode)

Groovy Verison:

Groovy Version: 2.3.6 JVM: 1.7.0_65 Vendor: Oracle Corporation OS: Linux

Grails Version:

Grails version: 2.4.3

Simplified Code:

import grails.test.mixin.Mock
@Mock([AnalyticFilters])
trait ControllerTestBase {
public void setupCommonStuff(boolean setupIdCall = false) {
params.devId = TEST_DEV_ID
    // mocking version filter
    params.version = "v${TEST_VERSION}"

    defineBeans{
       CacheService(cacheServiceMock: "createMock")
    }

    CommonParams.parseParams(params)

    cacheMock = applicationContext.getBean("cacheServiceMock")

    if(setupStoreIdCall) {
        cacheMock.demandExplicit.makeCompositeKey(0..20) { List<String> list ->
            def (String uuid, String orgUuid) = list
            return "foobar"
        }
    }

}
}

@TestFor(AuditController)
public class AuditControllerSpecs extends Specification implements ControllerTestBase {

private def auditServiceFactory

public String testAuditData = "{audit:'whatever'}"

public void setup() {
    setupCommonParams()

    defineBeans {
        auditServiceFactory(GrailsMock, AuditService)
        auditService(auditServiceFactory: "createMock")
    }
    auditServiceFactory = applicationContext.getBean("auditServiceFactory")
    auditServiceFactory.demand.writeEventToMongo { BasicDBObject data -> }
    controller.auditService = applicationContext.getBean('auditService', AuditService)
}

def "calling productAudit should return with 200 and OK"() {

    given:
    request.JSON = JSON.parse(testAuditData)
    request.method = 'POST'
    when:
    withFilters(action: "productAudit") {
        controller.productAudit()
    }
    then:

    def res = JSON.parse(response.text)

    expect:
    response.status == 200
    res.message == "OK"
    100 == 2
}

}

Stacktrace:

 [groovyc] org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
  [groovyc] General error during canonicalization: Comparison method violates its general contract!
  [groovyc] 
  [groovyc] java.lang.IllegalArgumentException: Comparison method violates its general contract!
  [groovyc]     at java.util.TimSort.mergeLo(TimSort.java:747)
  [groovyc]     at java.util.TimSort.mergeAt(TimSort.java:483)
  [groovyc]     at java.util.TimSort.mergeCollapse(TimSort.java:410)
  [groovyc]     at java.util.TimSort.sort(TimSort.java:214)
  [groovyc]     at java.util.TimSort.sort(TimSort.java:173)
  [groovyc]     at java.util.Arrays.sort(Arrays.java:659)
  [groovyc]     at java.util.Collections.sort(Collections.java:217)
  [groovyc]     at org.codehaus.groovy.transform.trait.TraitComposer.applyTrait(TraitComposer.java:183)
  [groovyc]     at org.codehaus.groovy.transform.trait.TraitComposer.doExtendTraits(TraitComposer.java:105)
  [groovyc]     at org.codehaus.groovy.control.CompilationUnit$4.call(CompilationUnit.java:188)
  [groovyc]     at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:1047)
  [groovyc]     at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:583)
  [groovyc]     at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:561)
  [groovyc]     at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:538)
  [groovyc]     at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:517)
  [groovyc]     at org.codehaus.groovy.tools.FileSystemCompiler.compile(FileSystemCompiler.java:59)
  [groovyc]     at org.codehaus.groovy.tools.FileSystemCompiler.doCompilation(FileSystemCompiler.java:215)
  [groovyc]     at org.codehaus.groovy.ant.Groovyc.runCompiler(Groovyc.java:1104)
  [groovyc]     at org.codehaus.groovy.ant.Groovyc.compile(Groovyc.java:1155)
  [groovyc]     at org.codehaus.groovy.grails.compiler.Grailsc.compile(Grailsc.java:78)
  [groovyc]     at org.codehaus.groovy.ant.Groovyc.execute(Groovyc.java:770)
  [groovyc]     at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
  [groovyc]     at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source)
  [groovyc]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  [groovyc]     at java.lang.reflect.Method.invoke(Method.java:606)
  [groovyc]     at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
  [groovyc]     at groovy.util.AntBuilder.performTask(AntBuilder.java:319)
  [groovyc]     at groovy.util.AntBuilder.nodeCompleted(AntBuilder.java:264)
  [groovyc]     at groovy.util.BuilderSupport.doInvokeMethod(BuilderSupport.java:147)
  [groovyc]     at groovy.util.AntBuilder.doInvokeMethod(AntBuilder.java:203)
  [groovyc]     at groovy.util.BuilderSupport.invokeMethod(BuilderSupport.java:64)

Caspian

Depends on how it is being used. can you add what are you up to? – Hadsall

Can you tell me which JVM version you use? – Nitride

Answer 1

The same exception occurs in our project which makes heavy use of traits:

java.lang.IllegalArgumentException: Comparison method violates its general contract!

My colleague found out that this happens as soon as a trait has more than 10 fields. The origin of this behavior is unknown to us.

As a workaround we make use of trait inheritance:

trait Foo extends MoreFoo {
    //this has 10 fields
}

trait MoreFoo{
    //this has some more fields but not more than 10
}

It is noteworthy that we use Groovy on Android so adjusting JVM options as proposed by ColimMc is not an option.

Squinty

had the problem with 10 fields in trait, removed one and all was normal again, interesting thing is all was ok until i restarted computer – Sparing

Just hit the exact same ambiguous compiler error with a trait with 10+ fields - lowering the number to <10 solved it - what a strange error (groovy-eclipse compiler 2.9.2-01, groovy-all 2.4.9. – Yezd

@TomBunting I am glad that you found this issue and did not waste more time on it. This is indeed a strange error, it is extremely difficult to locate when working with traits. – Squinty

Answer 2

It seems to me that there is a limit with script fields that use traits. If the number of fields from the implementation that is using a trait reaches a certain size (my case 34 methods) then this exception gets thrown. I'm currently running into this same issue that you have and I'm trying to solve it.

I was able to get around Groovy by using:

-Djava.util.Arrays.useLegacyMergeSort=true

as mentioned here: https://mcmap.net/q/49850/-quot-comparison-method-violates-its-general-contract-quot-timsort-and-gridlayout

I think it has to do with their GETTER_FIRST_COMPARATOR comparator where it doesn't return 0. It only returns 1 and -1 which I think is the reason why it mentions a contract violation.

Matthias