strip: access bookmark before getting a reference to changelog Bookmark access might invalidate the current changelog (to make sure both are in a reasonable synchronisation state). So we should grab the reference to changelog after we access bookmark. Otherwise we risk using a dead object for the whole strip process. (note: this dead object business probably requires a new layers of checking)

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}