[issue34944] Update _dirnameW to accept long path names

Change by Joe Pamer : -- keywords: +patch pull_requests: +9157 stage: -> patch review ___ Python tracker ___ ___ Python-bugs-list m

[issue34944] Update _dirnameW to accept long path names

New submission from Joe Pamer : The fix for issue 32557 updated os__getdiskusage_impl to use _dirnameW for obtaining the parent directory of a file. This would cause a regression if the path exceeded 260 characters, since _dirnameW currently returns -1 if given a path >= MAX_PATH in length.