annotate .arcconfig @ 43786:421ea5772039

copies: split the combination of the copies mapping in its own function

In some case, this part take up to 95% of the copy tracing that take about a
hundred second. This poor performance comes from the fact we keep duplciating
and merging dictionary that are mostly similar.

I want to experiment with smarter native code to do this, so I need to isolate
the function first.

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