view .arcconfig @ 35561:4c3a4bb31c0e

revsetlang: raise ParseError to report invalid format character

It's more common in revset and templater than raising Abort.

I have a couple more patches to address exceptions caused by bad format string
passed to revset() template function.

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