How to unhide a hidden (obsolete) changeset?

[Pierre-Yves David]

The changeset is still obsolete because you did not removed the 
obsolescence marker that make it so.

There is currently no easy//userfriendly way to remove this obsolescence 
marker. (This is is one of the reason evolution is still experimental)

If you want B to looks like A you could:

1) strip any hidden changeset in B `hg strip --hidden 'hidden()'`
2) remove all obsolesnce marker in B `mv .hg/store/obstore 
.hg/store/obstore.foo`
3) repull from A `hg pull A`