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Daniel Sun commented on GROOVY-9075: ------------------------------------ Gotcha. Let me look into the issue later ;) > The exception message should be more clear when a GroovyObject's metaClass is > wrong > ----------------------------------------------------------------------------------- > > Key: GROOVY-9075 > URL: https://issues.apache.org/jira/browse/GROOVY-9075 > Project: Groovy > Issue Type: Bug > Components: groovy-runtime > Affects Versions: 2.4.16, 3.0.0-alpha-4, 2.5.6 > Reporter: Xiaoguang Wang > Priority: Major > > If a GroovyObject's metaClass is overwritten by mistake, the accesses to the > instance may cause an exception with unclear message. > > We have met the problem too many times and have spent a lot of time on > debugging (and teaching everyone never to use `BeanUtils.copyProperties`, etc) > > If there is a try-catch (or some other check) in the runtime code and report > this problem more clearly, it will save everyone's time to debug. Or, is > there any better solution to this problem, eg: check the class type in > `MetaClassImpl.setProperty`, `DefaultGroovyMethods.setMetaClass` ? > > {code:java} > import groovy.transform.CompileStatic > //@CompileStatic > class C1 { > int x > } > //@CompileStatic > class C2 { > int x > } > //@CompileStatic > class TestGroovy { > static void main(String[] args) { > def c1 = new C1() > def c2 = new C2() > c1.metaClass = c2.metaClass //eg: > org.springframework.beans.BeanUtils.copyProperties > // or c1.setMetaClass(c2.getMetaClass()) > c1.x += 1 // crash here with unclear exception, but c1.setX() works > } > } > {code} > > {code:java} > /* > without @CompileStatic > Exception in thread "main" java.lang.IllegalArgumentException: object is not > an instance of declaring class > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > at java.lang.reflect.Method.invoke(Method.java:498) > at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98) > at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325) > at > org.codehaus.groovy.runtime.metaclass.MethodMetaProperty$GetBeanMethodMetaProperty.getProperty(MethodMetaProperty.java:76) > at > org.codehaus.groovy.runtime.callsite.GetEffectivePogoPropertySite.getProperty(GetEffectivePogoPropertySite.java:85) > at > org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGetProperty(AbstractCallSite.java:299) > with @CompileStatic > Exception in thread "main" java.lang.IllegalArgumentException: object is not > an instance of declaring class > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > at java.lang.reflect.Method.invoke(Method.java:498) > at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98) > at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325) > at groovy.lang.MetaClassImpl.setProperty(MetaClassImpl.java:2726) > at groovy.lang.MetaClassImpl.setProperty(MetaClassImpl.java:3785) > at C1.setProperty(TestGroovy.groovy) > at > org.codehaus.groovy.runtime.InvokerHelper.setProperty(InvokerHelper.java:213) > at > org.codehaus.groovy.runtime.ScriptBytecodeAdapter.setProperty(ScriptBytecodeAdapter.java:497) > */ > {code} -- This message was sent by Atlassian JIRA (v7.6.14#76016)