# Find the topmost dir common to all files
if len(incfiles) > 1:
topdir = os.path.commonprefix(incfiles)
+ # Check whether topdir is valid, as os.path.commonprefix() works on
+ # a character by character basis, rather than on path elements.
+ if not os.path.exists(topdir):
+ topdir = os.path.dirname(topdir) + os.path.sep
else:
topdir = os.path.dirname(incfiles[0]) + os.path.sep