[jira] [Comment Edited] (GROOVY-9086) @CompileStatic of closure calls with OWNER_FIRST fail at runtime with ClassCastException

["Eric Milles (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-9086?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16819543#comment-16819543 ] 

Eric Milles edited comment on GROOVY-9086 at 4/16/19 10:10 PM:
---------------------------------------------------------------

When the compiler gets to {{StaticInvocationWriter.tryImplicitReceiver}}, it has determined that the implicit receiver is "delegate.delegate".  That is your script is interpreted as:
{code:groovy}
@CompileStatic
void test() {
  m1 {
    m2 {
      this.delegate.delegate.c1Method()
    }
  }
}
{code}

It then converts to {{((C1) ((Closure) ((Test$_test_closure1$_closure2) this).getDelegate()).getDelegate()).c1Method()}}.  As you stated, the leftmost "getDelegate" should be "getOwner".  An instance of {{C2}} is the return value of this first call, which cannot be cast to {{Closure}}.


was (Author: emilles):
When the compiler gets to {{StaticInvocationWriter.tryImplicitReceiver}}, it has determined that the implicit receiver is "delegate.delegate".  That is your script is interpreted as:
{code:groovy}
@CompileStatic
void test() {
  m1 {
    m2 {
      this.delegate.delegate.c1Method()
    }
  }
}
{code}

It then converts to {{((C1) ((Closure) ((Closure) this).getDelegate()).getDelegate()).c1Method()}}.  As you stated, the leftmost "getDelegate" should be "getOwner".  An instance of {{C2}} is the return value of this first call, which cannot be cast to {{Closure}}.

> @CompileStatic of closure calls with OWNER_FIRST fail at runtime with ClassCastException
> ----------------------------------------------------------------------------------------
>
>                 Key: GROOVY-9086
>                 URL: https://issues.apache.org/jira/browse/GROOVY-9086
>             Project: Groovy
>          Issue Type: Bug
>          Components: Static compilation
>    Affects Versions: 2.5.6
>         Environment: WIndows7, Groovy 2.5.6, Java 8 + 11
>            Reporter: Andreas Turban
>            Priority: Major
>         Attachments: TestScript.groovy
>
>
> The attached script fails with a ClassCastException, when method m2 is annotated with 
>  
> {code:java}
> strategy = Closure.OWNER_FIRST
> {code}
>  but work with 
>  
> {code:java}
> strategy = Closure.DELEGATE_FIRST
> {code}
>  The expected system-out should be 
>  
> {code:java}
> c1Method called{code}
>  in both cases. The generated bytecode for closure Test$_test_closure1$_closure2.class contains a call to getDelegate() instead of getOwner() in case of Closure.OWNER_FIRST. But correctly generates code getOwner() in case of Closure.DELEGATE_FIRST.
> The resulting ClassCastException at runtime is:
> {code:java}
> java.lang.ClassCastException: Test$C2 cannot be cast to groovy.lang.Closure
> at Test$_test_closure1$_closure2.doCall(TestScript.groovy:28)
> at Test$_test_closure1$_closure2.doCall(TestScript.groovy)
> at Test.m2(TestScript.groovy:20)
> at Test$_test_closure1.doCall(TestScript.groovy:26)
> at Test$_test_closure1.doCall(TestScript.groovy)
> at Test.m1(TestScript.groovy:8)
> at Test.test(TestScript.groovy:25)
> at Test$test.call(Unknown Source)
> at TestScript.run(TestScript.groovy:42)
> {code}
> The wrong bytecode for case Closure.OWNER_FIRST:
> {code:java}
> public java.lang.Object doCall(java.lang.Object);
> descriptor: (Ljava/lang/Object;)Ljava/lang/Object;
> flags: ACC_PUBLIC
> Code:
> stack=1, locals=2, args_size=2
> 0: aload_0
> 1: checkcast #2 // class Test$_test_closure1$_closure2
> 4: invokevirtual #29 // Method getDelegate:()Ljava/lang/Object;
> 7: checkcast #4 // class groovy/lang/Closure
> 10: invokevirtual #30 // Method groovy/lang/Closure.getDelegate:()Ljava/lang/Object;
> 13: checkcast #32 // class Test$C1
> 16: invokevirtual #36 // Method Test$C1.c1Method:()V
> 19: aconst_null
> 20: areturn
> {code}
> The correct bytecode for case Closure.DELEGATE_FIRST:
> {code:java}
> public java.lang.Object doCall(java.lang.Object);
> descriptor: (Ljava/lang/Object;)Ljava/lang/Object;
> flags: ACC_PUBLIC
> Code:
> stack=1, locals=2, args_size=2
> 0: aload_0
> 1: checkcast #2 // class Test$_test_closure1$_closure2
> 4: invokevirtual #29 // Method getOwner:()Ljava/lang/Object;
> 7: checkcast #4 // class groovy/lang/Closure
> 10: invokevirtual #32 // Method groovy/lang/Closure.getDelegate:()Ljava/lang/Object;
> 13: checkcast #34 // class Test$C1
> 16: invokevirtual #38 // Method Test$C1.c1Method:()V
> 19: aconst_null
> 20: areturn
> {code}



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)