view .arcconfig @ 37173:05ff1a155a21

memctx: create parent contexts using "repo[p]" syntax

I want to reduce dependence on basectx.__new__() and move that code
over to repo.__getitem__().

Differential Revision: https://phab.mercurial-scm.org/D2968

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