[jira] Commented: (CAY-1008) Reverse relationships may not be correctly set if inheritance is used.

["Robert Zeigler (JIRA)" <de...@cayenne.apache.org>]

    [ https://issues.apache.org/cayenne/browse/CAY-1008?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12894#action_12894 ] 

Robert Zeigler commented on CAY-1008:
-------------------------------------

Turns out you don't even need inheritance to see this bug.
I duplicated this today with the following mapping:

db relationship:
artist -> paintings (one to many)
 
obj relationships:
artist.paintingList maps via the artist->paintings relationship as a java.util.List
artist.paintingsByTitle maps via the artist->paintings relationship as a java.util.Map, keyed on the painting title.

        Artist a = context.newObject(Artist.class);
        a.setName("Test Artist");
        context.commitChanges();
        assertEquals(a.getPaintingList().size(),0);
        assertEquals(a.getPaintingsByTitle().size(),0);//"A"
        Painting p = new Painting();
        p.setPrice(10.0);
        p.setTitle("Test Painting");
        p.setArtist(a);
        context.commitChanges();
        assertEquals(a.getPaintingList().size(),1);
        assertEquals(a.getPaintingsByTitle().size(),1);//"B"
                
        context.deleteObject(p);
        context.commitChanges();
        assertEquals(a.getPaintingList().size(),0);
        assertEquals(a.getPaintingsByTitle().size(),0);//"C"


If you leave the line labeled "A" in place, then "B" will fail.  If you comment out "A", "B" will pass (because the list won't be resolved until that point, so it will be resolved from the database, I'm presuming).  If you comment out "A", but leave "B" and "C", then C will fail (size will be 1).  If you comment out "A" and "B", then "C" passes.

I can slim down the mapping info and attach it, if that would be helpful.

> Reverse relationships may not be correctly set if inheritance is used.
> ----------------------------------------------------------------------
>
>                 Key: CAY-1008
>                 URL: https://issues.apache.org/cayenne/browse/CAY-1008
>             Project: Cayenne
>          Issue Type: Bug
>          Components: Cayenne Core Library
>    Affects Versions: 3.0
>            Reporter: Kevin Menard
>            Assignee: Andrus Adamchik
>
> Given two entities, Employee and Address, such that there is a one-to-many relationship between the two, it may be possible that reverse relationships are not fully set if inheritance is used.
> For example, let's say that HomeAddress extends Address, then the following fails:
> Employee e = context.newObject(Employee.class);
>         Address a = context.newObject(Address.class);
>         a.setToEmployee(e);
>         assertEquals(1, e.getAddresses().size());
>         assertEquals(0, e.getHomeAddresses().size());
>         HomeAddress ha = context.newObject(HomeAddress.class);
>         ha.setToEmployee(e);
>         assertEquals(2, e.getAddresses().size());
>         assertEquals(1, e.getHomeAddresses().size());
> The last assertion fails as e.getHomeAddresses() will return an empty list.
> On the face of it, the problem is that the ObjRel "addresses" is being set rather than "homeAddresses".  This is due to how ObjRelationship#getReverseRelationship() determines reverse relationships.  It does so by inspecting the relationship structure and if there's a match, returns it.  "addresses" and "homeAddresses" have the same structure and "addresses" is the first match found and returned.
> Simply reversing order or other similar tricks won't really do anything more for us though.  The real issue seems to be how to deal with multiple ObjRels that match to the same DbRel.  Each ObjRel does need to be updated in order for the graph to remain consistent.

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