# From customizing roundup with changes for handling
# current or new status being None.

# Note that None -> anything transition is allowed. Best to use a
# status auditor to make current not be none.

def checktransition(db, cl, nodeid, newvalues):
    ''' Check that the desired transition is valid for the "status"
        property.
    '''
    if not newvalues.has_key('status'):
        return
    current = cl.get(nodeid, 'status')
    if current is None:
        return  # can always move from none to state.
    new = newvalues['status']
    if new == current:
        return
    if new is None:
        ok = []
    else:
        ok = db.status.get(current, 'transitions')
    if new not in ok:
            raise ValueError, 'Status not allowed to move from "%s" to "%s"'%(
                db.status.get(current, 'name'), db.status.get(new, 'name'))

def init(db):
    db.issue.audit('set', checktransition)