Multiple-override race fixed

[Colin Watson]

I've just deployed some fixes [1] to the "dominator" component of
Launchpad's archive publisher (the part that decides which older
publications have been superseded by newer ones) to sort out the
notorious [2] multiple-override race.

Until today, if override changes were made to the same
architecture-independent binary package more than once in the same
publisher cycle, then all the publications of that binary package in
that suite would incorrectly be considered superseded and the package
would effectively disappear from the archive.  This was obviously
terrible but also in a very delicate piece of code that was hard to fix.

This should now be fixed, so if you're an archive admin and have been
being very careful about avoiding this bug, you can now stop being
careful about that.  Please let me know if you see any remaining
oddities with how overrides are processed.

[1] https://code.launchpad.net/~cjwatson/launchpad/multiple-override-race/+merge/368023
[2] In some very limited circles.

-- 
Colin Watson                                       [cjwatson at ubuntu.com]