forEach broken in build 48?

[Arul Dhesiaseelan]

Awesome, thanks for the details.

On Fri, Jul 27, 2012 at 12:32 AM, Maurizio Cimadamore <
maurizio.cimadamore at oracle.com> wrote:

> On 26/07/12 10:39, Maurizio Cimadamore wrote:
> > On 26/07/12 03:53, bitter_fox wrote:
> >> Hi, Arul and Mike
> >> I guess Revision(langtools):1430[1] has a problem.
> >>
> >> In LambdaTranslator#makeFunctionalDescriptorType:
> >>           return erased ? types.erasure(descType) : descType;
> >>
> >> This is wrong I think.
> > Why do you think it's wrong? The code is meant to erase the descriptor
> > type only if the erased flagh is set (which only is when doing 292
> > translation).
> >
> > Maurizio
> Also, while I see the problem in b48, I'm not able to reproduce on a
> freshly built lambda repo, which prints out the correct sequence of names:
>
> Alice
> Bob
> Charlie
> Dave
>
> After looking at the differences in the generated code, I realized that
> the problem was caused by a problem with constant folding that I knew
> about and fixed yesterday ;-)
>
> Here's the culprit:
>
> *** Good code ***
>
> public void apply(java.lang.String);
>    Code:
>     Stack=2, Locals=2, Args_size=2
>     0:    aload_0
>     1:    getfield    #4; //Field rec$:Ljava/io/PrintStream;
>     4:    aload_1
>     5:    invokevirtual    #5; //Method
> java/io/PrintStream.println:(Ljava/lang/String;)V
>     8:    return
>
> *** Bad code ***
>
> public void apply(java.lang.String);
>    Code:
>     Stack=2, Locals=2, Args_size=2
>     0:    aload_0
>     1:    getfield    #4; //Field rec$:Ljava/io/PrintStream;
>     4:    ldc    #5; //String Dave
>     6:    invokevirtual    #6; //Method
> java/io/PrintStream.println:(Ljava/lang/String;)V
>     9:    return
>
> As you can see, the compiler has erroneously constant folded the access
> to the lambda parameter, thinking that the result would always be
> 'Dave'. The problem lies in type inference of Arrays.asList which was
> erroneously returning a constant type whose value was 'Dave' (the last
> constant seen in the varargs call). This was caused by a missing call to
> 'baseType' in Resolve.java which has now been corrected.
>
> Maurizio
> >> I tried this one and the problem looks resolved:
> >>           return erased ? descType : types.erasure(descType);
> >>
> >> Please ignore this mail if you already notice that.
> >>
> >> [1]:
> http://mail.openjdk.java.net/pipermail/lambda-dev/2012-July/005187.html
> >>
> >> Regards,
> >> bitter_fox
> >>
> >>
> >> 2012/7/26 Mike Duigou <mike.duigou at oracle.com>
> >>
> >>> I've looked into the problem and am able to replicate it. I did some
> >>> debugging and it appears to be a problem in the VM. I am notifying
> those
> >>> working on this area.
> >>>
> >>> Mike
> >>>
> >>>
> >>> On Jul 21 2012, at 01:39 , Arul Dhesiaseelan wrote:
> >>>
> >>>> Hi,
> >>>>
> >>>> It looks like forEach is broke in the latest build. It always prints
> the
> >>>> last item in the collection. It works fine in b45. It works in b48
> only
> >>> if
> >>>> we expand the code, not if we perform method reference on an instance.
> >>>>
> >>>> public class InstanceMethodReference {
> >>>>
> >>>>      public static void main(String[] args) {
> >>>>          Arrays.asList("Alice", "Bob", "Charlie",
> >>>> "Dave").forEach(System.out::println);//INCORRECT RESULT
> >>>>          Arrays.asList("Alice", "Bob", "Charlie", "Dave").forEach(new
> >>>> MyBlock(System.out));//CORRECT RESULT
> >>>>      }
> >>>>
> >>>>      public static class MyBlock implements Block<String> {
> >>>>          PrintStream ps;
> >>>>
> >>>>          public MyBlock(PrintStream ps) {
> >>>>              this.ps = ps;
> >>>>          }
> >>>>
> >>>>          @Override
> >>>>          public void apply(String s) {
> >>>>              ps.println(s);
> >>>>          }
> >>>>      }
> >>>> }
> >>>>
> >>>> build45 correctly prints:
> >>>> Alice
> >>>> Bob
> >>>> Charlie
> >>>> Dave
> >>>> Alice
> >>>> Bob
> >>>> Charlie
> >>>> Dave
> >>>>
> >>>> build48 prints:
> >>>> Dave
> >>>> Dave
> >>>> Dave
> >>>> Dave
> >>>> Alice
> >>>> Bob
> >>>> Charlie
> >>>> Dave
> >>>>
> >>>>
> >>>> -Arul
> >>>>
> >>>
> >
>
>
>