<https://code.edge.launchpad.net/~spiv/bzr-builder/merge-subdirs-479705/+merge/14979> has been abandoned. To be precise, it is superseded by <https://code.edge.launchpad.net/~spiv/bzr-builder/merge-subdirs-479705/+merge/31251>, which is targeted to a different branch (hence I could not use "Resubmit proposal" to supersede it).
So the most accurate status for the old proposal would be something like "Abandoned" or "Rejected". There is no prospect of that proposal being accepted and merged for that target (because that target is never going to change). I do not want to delete it because it contains valuable discussion.
However the only available statuses are: Work in progress, Needs review, and Merged. None of these is at all accurate. When the new proposal is merged, then it's probably a tolerable hack to mark this one Merged, but that's certainly not the case right now.
So I am left with a merge proposal with a wrong status that I cannot correct, not even approximately.
wgrant on IRC says this is because I'm not a reviewer for that branch. It's true, but I am the submitter, and more importantly I am the person driving the work on this change, so I ought to be able to withdraw my proposal from review. If I'm considered fit to propose a change, I should also be considered fit to revoke that when I find the change is no longer appropriate for whatever reason. (In this case because a different merge proposal has effectively superseded it, but it's easy to imagine other cases.)