Tags cache cleanup for Mercurial 6.1.1
Mercurial 6.1.1 will automatically be included with next release. It contains a fix for a bug with tags after merges that needs server-side cleaning (also to stop propagation to clients).
We'll need a background migration that amounts to this:
rm .hg/cache/*tag*
hg debugupdatecache
Problem underlined by the merge of Heptapod Shell in the course of #658 (closed), and not fixed by updating Mercurial on the client side.