merged two branches, and pushed, how to backout/strip?

[Marcin Kasperski]

Why is the whole machinery needed?

>From practical point of view, just update to pre-merge changeset, make
some irrelevant commit there (so there is natural default continuation),
bookmark merge changeset as preliminary change and be done. Development
will continue from pre-merge changeset. Once you are really ready to
merge you can use this merge as „partial trampoline” (continue from it
instead of merging from scratch) and finally merge itself too.