CachedFilesMixin url_converter creates url for incorrect file

[antonlitvinenko]

I think CachedFilesMixin has a bug somewhere around lines (storage.py lines 200-213)

            url_parts = url.split('/')
            parent_level, sub_level = url.count('..'), url.count('/')
            if url.startswith('/'):
                sub_level -= 1
                url_parts = url_parts[1:]
            if parent_level or not url.startswith('/'):
                start, end = parent_level + 1, parent_level
            else:
                if sub_level:
                    if sub_level == 1:
                        parent_level -= 1
                    start, end = parent_level, sub_level - 1
                else:
                    start, end = 1, sub_level - 1
            joined_result = '/'.join(name_parts[:-start] + url_parts[end:])

In my case I enter this block with: name_parts = [u'css', u'plugins', u'toaster.css'] and url = '/assets/images/icons/fancy_close.png' and expect joined_result in the end be images/icons/fancy_close.png, but instead it is icons/fancy_close.png.

For a url='/assets/images/glyphicons-halflings.png' it seems to work correct.

[antonlitvinenko]

I was able to overcome this by monkey-patching and changing to

            if parent_level or not url.startswith('/'):
                start, end = parent_level + 1, parent_level
            else:
                if sub_level:
                    if sub_level == 1:
                        parent_level -= 1
                    start, end = parent_level, 1 # <---- USING '1' HERE INSTEAD OF 'sub_level - 1'
                else:
                    start, end = 1, sub_level - 1

It works in my env, though I am not sure if this is correct.