[GROOVY-7054] Read Only Property not resolved correctly at runtime (w/CompileDynamic)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.4
• Fix Version/s: 2.3.7, 2.4.0-beta-4
• Component/s: Compiler
• Environment: Windows
• Assignee: Jochen Theodorou
• Reporter: Brad Miller
• Created: 02/Sep/14 16:29
• Updated: 17/Dec/14 13:25
• Resolved: 03/Sep/14 07:33

Description

I hit an issue where I was getting a MissingPropertyException if I used @CompileDynamic, but the exception went away with @CompileStatic. Below is a simple junit test that isolates the behavior, and the underlying issue is how a read-only private property (via getter) of a parent class is resolved at runtime by @CompileDynamic versus @CompileStatic. The CompileDynamicParentPrivateTest.testCDPrivate() test throws a runtime MissingPropertyException when a method in the parent class tries to access the the parent class's private property 'foo' (as opposed to via getFoo())

One possible explanation - it appears that the groovy 'foo' property is resolved dynamically when using @CompileDynamic, and as the property is private within the parent class the resolution on the child instance fails (however, why does getFoo() succeed then?). When @CompileStatic is used, the normal (java) lexical scoping rules apply, and the parent private property can be resolved correctly within the parent method.

1. Is this a bug, or an expected difference in behavior for @CompileStatic / @CompileDynamic?
2. And is my explanation correct as to what is happening?
3. And how can getFoo() succeed, but 'foo' fail, when using @CompileDynamic? Shouldn't they always behave the same?

Thanks,
Brad

-----------------------------------
Groovy 2.3.4

testCSPrivate succeeds, while second test (testCDPrivate) fails with following exception on second println statement:
groovy.lang.MissingPropertyException: No such property: foo for class: myBugReport.bug2.CDChild
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:50)
at org.codehaus.groovy.runtime.callsite.GetEffectivePogoPropertySite.getProperty(GetEffectivePogoPropertySite.java:84)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:231)
at myBugReport.bug2.CDParent.printWhichAccessesPrivatePropOfParent(CompileDynamicParentPrivateTest.groovy:53)
at myBugReport.bug2.CDParent$printWhichAccessesPrivatePropOfParent.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 myBugReport.bug2.CompileDynamicParentPrivateTest.testCDPrivate(CompileDynamicParentPrivateTest.groovy:22)

-----------------------------------

package myBugReport.bug2

import groovy.transform.CompileDynamic
import groovy.transform.CompileStatic
import org.junit.Test

class CompileDynamicParentPrivateTest
{
  // This test SUCCEEDS as CompileStatic parent class can access private read-only property 'foo'
  @Test
  public void testCSPrivate()
  {
    CSChild csChild = new CSChild()
    csChild.printWhichAccessesPrivatePropOfParent()
  }

  // This test FAILS as CompileDynamic parent class can NOT access private read-only property 'foo'
  @Test
  public void testCDPrivate()
  {
    CDChild cdChild = new CDChild()
    cdChild.printWhichAccessesPrivatePropOfParent()
  }
}

@CompileStatic
class CSParent
{
  // Read-only property where only the getter is defined (without a backing field)
  private String getFoo() { return "bar" }

  void printWhichAccessesPrivatePropOfParent()
  {
    System.out.println("Current value of getFoo() is: " + getFoo())    // works
    System.out.println("Current value of foo is: " + foo)       // works with CompileStatic only
  }
}

@CompileStatic
class CSChild extends CSParent
{
}

@CompileDynamic
class CDParent
{
  // Read-only property where only the getter is defined (without a backing field)
  private String getFoo() { return "bar" }

  void printWhichAccessesPrivatePropOfParent()
  {
    System.out.println("Current value of getFoo() is: " + getFoo())    // works
    System.out.println("Current value of foo is: " + foo)       // foo breaks with CompileDynamic only
  }
}

@CompileDynamic
class CDChild extends CDParent
{
}