On 10/19/20, Steve Dower <steve.do...@python.org> wrote: > On 19Oct2020 1242, Steve Dower wrote: >> On 15Oct2020 2239, Rob Cliffe via Python-Dev wrote: >>> TLDR: In os.scandir directory entries, atime is always a copy of mtime >>> rather than the actual access time. >> >> Correction - os.stat() updates the access time to _now_, while >> os.scandir() returns the last access time without updating it. > > Let me correct myself first :) > > *Windows* has decided not to update file access time metadata *in > directory entries* on reads. os.stat() always[1] looks at the file entry > metadata, while os.scandir() always looks at the directory entry metadata. > > My suggested approach still applies, other than the bit where we might > fix os.stat(). The best we can do is regress os.scandir() to have > similarly poor performance, but the best *you* can do is use os.stat() > for accurate timings when files might be being modified while your > program is running, and don't do it when you just need names/kinds (and > I'm okay adding that note to the docs).
If this is the correction to which you're referring in the previous message, I assumed you stood by the claim that os.stat() may update st_atime. That shouldn't be the case, so there shouldn't be anything that needs to be fixed there, unless I'm missing what you think needs to be fixed. If it's actually a problem, then I'd really, really like a test case that reproduces it. If it was just a misinterpreted test case or mis-remembered fact, then that's good news for me. ;-) Regarding updating the access time in the directory entry, in my previous reply I explained that NTFS should update it with a one-hour granularity. With FAT, it's daily. Regarding the view that this is only about "accurate timings when files might be being modified while your program is running", in my previous messages I stressed that the directory entry for a hard link may have the wrong size, change time, write time, and access time if it wasn't the last link used to update the file. That has nothing to do with the file being modified while the program is running. It's a stale directory entry. If you call os.stat() on the stale link, NTFS will update it with the correct metadata. _______________________________________________ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/SUGIZ6OAXOD37USVBWAW7JRSUDBSMG7Q/ Code of Conduct: http://python.org/psf/codeofconduct/
