Code review comment for lp:~deryck/launchpad/do-the-right-thing-dupe-move-78596

Overall, the changes look good. I only have one concern (sorry for coming up so late with it...): We have the new behaviour that marking bug A as a duplicate of bug B changes all old duplicates of bug A into duplicates of bug B. This is not recorded in the activity log of the duplicates, leading to the odd situation that you might have bug C marked as a duplcate of bug B, while the activity log says that it is a duplicate of bug A...

Also, having activity log entries for the changes of the duplicate_of value gives us the opportunity to revert the duplicate_of value of bug C, when bug A is "unmarked" as a duplicate of bug B.

But that's something for another branch (assuming that we think it is worth the effort), so I'm marking this one as approved. thanks for the tedious work of cleaning up the duplicate_of handling!