On Wed, Sep 15, 2021 at 4:20 AM Steven D'Aprano <steve@pearwood.info> wrote:
On Wed, Sep 15, 2021 at 08:53:21PM +1000, Chris Angelico wrote:
Sometimes there is no valid path to something,
I don't understand what you mean by that. If there is no valid path to something, where exactly are you cd'ing to, and how does it help you with the thing that has no valid path to it?
No one has mentioned the other case where cd'ing somewhere makes paths suddenly valid, and that is for long path names. Once you pass PATH_MAX length your only options are to cd as deep as possible and continue relatively, or to pass dir fds. The second is perhaps the better option, but harder to implement as you have to handle extra fds and remember to clean them up and I at least never remember how to thread fds through python code without going and looking it up. This also brings up the issue of how to restore the prior working directory. Just remembering its path and calling a new chdir will fail, both in the long path case and in the case that the old dir was deleted since last visit. We could hold an open fd before leaving the old cwd, and that should allow us to return in both cases. However I don't know how others feel about holding on to dir fds, especially essentially hidden ones; it sounds ripe for FS deadlock. Regards, ~Jeremiah