[GROOVY-6508] Outer class property dispatcher called by an inner class's propertyMissing looks for attributes/fields rather than properties on the outer class

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.2.2
• Component/s: ast builder
• Assignee: Jochen Theodorou
• Reporter: Luke Kirby
• Created: 29/Dec/13 14:28
• Updated: 15/Oct/15 18:19
• Resolved: 02/Jan/14 10:03

Description

Appears to affect all versions such the introduction of inner classes in 1.7.

I have a unit test and bugfix and a pull request will be forthcoming.

Consider the following:

class BaseFieldBearer {
    String baseField = 'baseValue'    
}

class BaseFieldBearerSub extends BaseFieldBearer {

    String getBaseFieldViaInner() {
        // An easy way to create an inner class and have it resolve something
        new java.util.concurrent.Callable<String>() {
            String call() {                
                baseField
            }
        }.call();
    }
}

BaseFieldBearerSub s = new BaseFieldBearerSub()
assert s.baseFieldViaInner == s.baseField

BaseFieldBearerSub.baseFieldViaInner will fail with the following:

Exception in thread "main" groovy.lang.MissingFieldException: No such field: baseField for class: BaseFieldBearerSub
        at groovy.lang.MetaClassImpl.getAttribute(MetaClassImpl.java:2628)
        at groovy.lang.MetaClassImpl.getAttribute(MetaClassImpl.java:3466)
        at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.getGroovyObjectField(ScriptBytecodeAdapter.java:352)
        at BaseFieldBearerSub.this$dist$get$2(GroovyXXXBug.groovy)
        at BaseFieldBearerSub$1.propertyMissing(GroovyXXXBug.groovy)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
        at groovy.lang.MetaClassImpl.invokeMissingProperty(MetaClassImpl.java:778)
        at groovy.lang.MetaClassImpl$12.getProperty(MetaClassImpl.java:1896)
        at org.codehaus.groovy.runtime.callsite.GetEffectivePogoPropertySite.getProperty(GetEffectivePogoPropertySite.java:84)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:231)
        at BaseFieldBearerSub$1.call(GroovyXXXBug.groovy:32)
        at BaseFieldBearerSub$1.call(GroovyXXXBug.groovy)
        at java_util_concurrent_Callable$call.call(Unknown Source)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:112)
        at BaseFieldBearerSub.getBaseFieldViaInner(GroovyXXXBug.groovy:30)
        at BaseFieldBearerSub$getBaseFieldViaInner.call(Unknown Source)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:112)
        at GroovyXXXBug.testInnerClassAccessingBaseFieldProperty(GroovyXXXBug.groovy:11)
        at GroovyXXXBug$testInnerClassAccessingBaseFieldProperty.call(Unknown Source)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:112)
        at GroovyXXXBug.main(GroovyXXXBug.groovy:17)

BaseFieldBearerSub.this$dist$get$2 is a dispatcher method that's meant to resolve a named property in the outer class, but instead of using ScriptBytecodeAdapter.getGroovyObjectProperty it calls ScriptBytecodeAdapter.getGroovyObjectField. If baseField were a property in the subclass then this would normally go unnoticed, as the attribute would be found (though any property getter method would be ignored). I expect that's why I couldn't find other references to this bug.

The code at fault appears to be in InnerClassVisitorHelper as the dispatcher method uses an AttributeExpression instead of a PropertyExpression. I can't imagine there's any reason for the dispatcher to only consider attributes rather than properties, but I'm open to being corrected!