Merge did not work as expected

This was a result of a misunderstanding of how reverts and DAGgy ancestry combine - there was a partial revert of the changes on the feature branch present on another feature branch which had previously landed to the trunk.

Edited transcript of my explanation from #bzr:
< maxb> Ronnie: Actually, *you* reverted your own changes
< Ronnie> maxb: how did i do that, and in what revision. how can i see such ' mistakes' ?
< maxb> revid:<email address hidden> "User syncing should now work"
< maxb> So, at some point in the past, you merged your 570613 branch into your 611304 branch. Then, on your 611304 branch, you reverted most of the changes. Later, the 611304 branch got merged into the upstream branch
< maxb> So, there's now a revision merged to trunk which says to bzr "I know about those changes, and they're backed out"
< maxb> Right, so I think the best way to get out of this is as follows:
< maxb> First you merge the revision *before* the revert into your current branch. So by that I mean you merge revid:<email address hidden> into your 570613 branch
< maxb> Then you merge the revision that did the revert i.e. revid:<email address hidden> into your 570613, branch, but you revert the revert before committing - i.e. "bzr revert ." - the . is important
< maxb> it says to revert the tree, but not the what-I-have-merged metadata
< maxb> By doing this you are telling bzr "I know about this revert, but I've decided I don't want it to happen"
< maxb> After which you should be in a position to consider doing the original merge you were intending
< maxb> Ronnie: I've pushed the result of those three merges to lp:~maxb/loco-directory/710969-example in case an example is helpful

Here are the precise commands I used, in case that is helpful:

bzr branch lp:~loco-directory-dev/loco-directory/0.2
bzr branch lp:~ronnie.vd.c/loco-directory/570613
cd 570613
bzr merge -r revid:<email address hidden> ../0.2/
bzr ci -m "Merge 611304 branch."
bzr merge -r revid:<email address hidden> ../0.2/
bzr revert .
bzr ci -m "Merge unintentional revert, reverting it."
cd ../0.2
bzr merge ../570613/
bzr ci -m "Merge 570613 to trunk."
bzr push lp:~maxb/loco-directory/710969-example