.arcconfig

svnsubrepo: check if subrepo is missing when checking dirty state (issue5657)

During an hg convert command, subrepos are not checked out. However, a
manifestmerge may occur during an hg convert if there is a merge
commit, which in particular will check the dirty state of subrepos.
Before this change, the lack of a checked out subrepo would error out.

This check for svn subrepos is modelled after 2fdea636f254 for git
subrepos.

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