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From "ASF subversion and git services (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (TAP5-1493) Property expressions on properties that are covariant on a base class use the type of the base class property, not the covariant subclass
Date Fri, 27 Jun 2014 13:06:25 GMT

    [ https://issues.apache.org/jira/browse/TAP5-1493?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14045916#comment-14045916
] 

ASF subversion and git services commented on TAP5-1493:
-------------------------------------------------------

Commit 5db1364e9cf2e5087ee00508fe7382ac4ddb70a8 in tapestry-5's branch refs/heads/master from
[~thiagohp]
[ https://git-wip-us.apache.org/repos/asf?p=tapestry-5.git;h=5db1364 ]

TAP5-1493: as I cannot reproduce the issue in my machine, even using
Java 6, I'm committing a little change to know how it'll turn out in
tests.

> Property expressions on properties that are covariant on a base class use the type of
the base class property, not the covariant subclass
> -----------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: TAP5-1493
>                 URL: https://issues.apache.org/jira/browse/TAP5-1493
>             Project: Tapestry 5
>          Issue Type: Bug
>          Components: tapestry-core, tapestry-ioc
>    Affects Versions: 5.2
>            Reporter: Howard M. Lewis Ship
>            Priority: Critical
>              Labels: month-of-tapestry
>             Fix For: 5.4
>
>
> public abstract class AbstractFoo
> {
>  public abstract AbstractBar getBar();
> }
> public class Foo extends AbstractFoo
> {
>  public Bar getBar();
> }
> Here property bar is covariant; the subclass (Foo) changes the type of the return value
(from AbstractBar to just Bar). Assuming that Bar is a subclass of AbstractBar, that's fine.
> The bug is that in this circumstance, the PropertyConduitSource sees the type of
> property "bar" of class Foo as AbstractBar, not Bar.
> Interestingly, a little debugging showed that the getter method for property bar was
"public AbstractBar Foo.getBar()" ... in other words, much like with Generics, covariant return
types may be largely
> a fiction of the compiler inserting the necessary casts in place.



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