GeezerVison is showing github.com — Refactor `nt._path_is*` & `nt._path_[l]exists` · Issue #118507 · python/cpython
Refactor nt._path_is* & nt._path_[l]exists #118507DescriptionFeature or enhancement
Proposal:
Quoting @eryksun:
I agree that all of these _path_is* and _path_[l]exists helpers are a lot of code to maintain, taken together. It could be refactored into smaller inline helper functions that can be reused, which would also make the code more readable.
Has this already been discussed elsewhere?
This is a minor feature, which does not need previous discussion elsewhere
Links to previous discussion of this feature:
Linked PRs
Activitynineteendo commented on May 6, 2024 ContributorAuthor More actions Eryk, do you have any ideas to clean them up (besides the simpler error handling)? eryksun commented on May 7, 2024 nineteendo commented on May 7, 2024 ContributorAuthor More actions Good start, we probably need a follow_symlinks option for _testFileTypeByName to use LSTAT() though. eryksun commented on May 7, 2024 eryksun commented on May 7, 2024 nineteendo commented on May 8, 2024 ContributorAuthor More actions Did you speed something up, because it's only 3 lines less than the old code. eryksun commented on May 8, 2024 My goal was to remove duplicated code and divide the work into two separate operations that can be understood and modified independently, written in a way that I think is easy to understand. This reduces the maintenance burden. I also added internal support for checking for mount points, in case we implement _path_isjunction().
I added a GetFileType() check in the by-handle code. When combined with the diskOnly parameter, the GetFileType() check makes it safer to check an open file descriptor since the check is implemented directly in the I/O manager without trying to acquire the file lock. If GetFileInformationByHandleEx() is called on a handle for a synchronous-mode pipe, it could block indefinitely. For example, with the current implementation in 3.12:
>>> pr, pw = os.pipe()
>>> threading.Thread(target=os.read, args=(pr, 1)).start()
>>> os.path.isfile(pr)
^C Also, given the system's named-pipe filesystem (NPFS) support for basic file information (anonymous pipes are also in NPFS, but they're like unlinked open files in POSIX), the GetFileType() check avoids classifying pipes as regular files. Again, with the current implementation in 3.12:
>>> pr, pw = os.pipe()
>>> os.path.isfile(pr)
True nineteendo commented on May 8, 2024 ContributorAuthor More actions OK, that explains why the code isn't much shorter. I added a test for the second issue. The first one seems difficult to test. added a commit that references this issue on May 21, 2024gh-118507 : Refactor `nt._path_is*` to improve applicability for othe… added a commit that references this issue on May 22, 2024gh-118507 : Refactor `nt._path_is*` to improve applicability for othe…
MetadataMetadataDevelopmentNo branches or pull requestsIssue actions
|