[jira] [Closed] (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

["Thiago H. de Paula Figueiredo (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TAP5-1493?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Thiago H. de Paula Figueiredo closed TAP5-1493.
-----------------------------------------------

       Resolution: Fixed
    Fix Version/s: 5.4

I'm not sure when this issue was fixed, but in 5.4 I cannot reproduce it. I've added some tests based on the code samples by Howard and Robert.

> 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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