match: introduce explicitdir and traversedir match.dir is currently called in two different places: (1) noting when a directory specified explicitly is visited. (2) noting when a directory is visited during a recursive walk. purge cares about both, but commit only cares about the first. Upcoming patches will split the two cases into two different callbacks. Why bother? Consider a hypothetical extension that can provide more efficient walk results, via e.g. watching the filesystem. That extension will need to fall back to a full recursive walk if a callback is set for (2), but not if a callback is only set for (1).

from mercurial.hg import parseurl

def testparse(url, branch=[]):
    print '%s, branches: %r' % parseurl(url, branch)

testparse('http://example.com/no/anchor')
testparse('http://example.com/an/anchor#foo')
testparse('http://example.com/no/anchor/branches', branch=['foo'])
testparse('http://example.com/an/anchor/branches#bar', branch=['foo'])
testparse('http://example.com/an/anchor/branches-None#foo', branch=None)
testparse('http://example.com/')
testparse('http://example.com')
testparse('http://example.com#foo')