Martin> I don't think any change is necessary. os.path.commonprefix Martin> works just fine on path components: ...
>>> os.path.commonprefix(["/export/home", "/etc/passwd"]) '/e'
This calls it with strings, not with path components. As I said, it works fine for path components:
py> os.path.commonprefix([f.split('/') for f in ["/export/home", "/etc/passwd"]]) ['']
See http://bugs.python.org/issue4755 for what I think is a function with more predictable behavior given that we are discussing paths and not just strings.
See above: the function works for lists as well.