layouts: fix crash when importing hgsubversion itself (issue #402) Mercurial extensions are a bit weird: they aren't normally in sys.path, so you can't assume that "import hgsubversion" works. Luckily, Mercurial sneaks a little treat into sys.modules so that "import hgext_hgsubversion" does work. In fact, to get things working *as a Mercurial extension*, all that's needed is that trivial change to two import lines, in layouts/detect.py and layouts/standard.py. Unfortunately, hgsubversion is also imported as a Python module, in its own test suite. In that context, there is no "hgext_" trick -- unless we do it in ourselves, which I've done in TestBase.setUp(). That would work fine ... except that test_util imports from hgsubversion, which ends up importing hgsubversion.layouts.{detect,standard}, which want the "hgext_" trick to work. But it hasn't been done yet when we're still importing; it doesn't happen until setUp() runs. So make those two imports happen late, in the functions that need them. Incidentally, this is only necessary to support Mercurial <= 2.7. Mercurial got a bit smarter in 2.8: http://selenic.com/repo/hg/rev/621a26eb3a99

function verify_current_revision()
{
    /bin/rm -rf *
    exportcmd="svn export `hg svn info 2> /dev/null | grep '^URL: ' | sed 's/URL: //'`@`hg svn info | grep ^Revision | sed 's/.*: //;s/ .*//'` . --force"
    `echo $exportcmd` > /dev/null
    x=$?
    if [[ "$x" != "0" ]] ; then
        echo $exportcmd
        echo 'export failed!'
        return 255
    fi
    if [[ "`hg st | wc -l | python -c 'import sys; print sys.stdin.read().strip()'`" == "0" ]] ; then
        return 0
    else
        if [[ $1 != "keep" ]] ; then
            revert_all_files
        fi
        return 1
    fi
}

function revert_all_files()
{
    hg revert --all
    hg purge
}