Uncommit Performance Notes
==========================

Specification of uncommit
-------------------------

``uncommit`` removes revisions from the head of a branch.  (By default, only
the very latest revision is removed, but optionally more can be taken.)
Uncommit does not affect the repository (garbage collection is a separate
step and not done by default).  The working tree is not logically
modified (revert is a different operation), except as described below
about merges.

Uncommit can be performed on either a branch or a working tree (and
implicitly its branch.)

If the uncommitted revisions includes one or more merges, after the
uncommit those revisions are in the working tree's list of pending merges,
because their tree changes are still present in the tree.

For a bound branch, uncommit fails unless the local branch is up to date.