Comment 2 for bug 851047

SPPH.ancestor is set for new copies, but nobody has ever gone back to populate it for old ones. Worse, it briefly had a different meaning where each SPPH had it set to the previous version of the same package. Witness the chaos (where I assert that both these counts should be 0 if this transformation is going to be sensible):

launchpad_dogfood=# SELECT COUNT(*) FROM sourcepackagepublishinghistory spph, sourcepackagerelease spr WHERE spph.sourcepackagerelease = spr.id AND (spph.archive != spr.upload_archive OR spph.distroseries != spr.upload_distroseries) AND spph.ancestor IS NULL;
 count
--------
 809350
(1 row)

launchpad_dogfood=# SELECT COUNT(*) FROM sourcepackagepublishinghistory spph, sourcepackagerelease spr WHERE spph.sourcepackagerelease = spr.id AND spph.archive = spr.upload_archive AND spph.distroseries = spr.upload_distroseries AND spph.ancestor IS NOT NULL;
 count
-------
  4576
(1 row)

As a result I don't think ancestor can be used without some fairly substantial garbo job work to clean all this up. (I'm not volunteering.)

I'm handling the display of SPPH.creator as bug 1032857.