-
-
Notifications
You must be signed in to change notification settings - Fork 30.8k
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
gh-68320, gh-88302 - Allow for pathlib.Path
subclassing
#31691
gh-68320, gh-88302 - Allow for pathlib.Path
subclassing
#31691
Conversation
Users may wish to define subclasses of `pathlib.Path` to add or modify existing methods. Before this change, attempting to instantiate a subclass raised an exception like: AttributeError: type object 'PPath' has no attribute '_flavour' Previously the `_flavour` attribute was assigned as follows: PurePath._flavour = xxx not set!! xxx PurePosixPath._flavour = _PosixFlavour() PureWindowsPath._flavour = _WindowsFlavour() This commit replaces it with a `_pathmod` attribute, set as follows: PurePath._pathmod = os.path PurePosixPath._pathmod = posixpath PureWindowsPath._pathmod = ntpath Functionality from `_PosixFlavour` and `_WindowsFlavour` is moved into `PurePath` as underscored-prefixed classmethods. Flavours are removed.
Misc/NEWS.d/next/Library/2022-03-05-02-14-09.bpo-24132.W6iORO.rst
Outdated
Show resolved
Hide resolved
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
…ygale/cpython into bpo-44136-remove-pathlib-flavour-2
Makes the code a little more direct.
Hey @brettcannon, just bumping this PR in case it dropped off your radar. |
@barneygale it hasn't, but my PR review queue is 11 PRs deep, this is in position 7, and I have worry about getting PEP 594 done in time for 3.11b1. Plus I have some stuff I need to get done for work this month which is eating into my paid OSS time. |
pathlib.Path
subclassing.pathlib.Path
subclassing.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Most of the comments are either code touch-ups or asking to make the code more self-describing.
A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated. Once you have made the requested changes, please leave a comment on this pull request containing the phrase |
Co-authored-by: Brett Cannon <brett@python.org>
Thanks for taking the time to see this through, @barneygale ! |
Thank you so much for your help with this Brett! Hope you have a restful break :) |
@barneygale Congrats! You started so long ago but we finally get the results. It's an amazing effort. |
* Correct CVE-2020-10735 documentation (python#100306) * pythongh-94912: Added marker for non-standard coroutine function detection (python#99247) This introduces a new decorator `@inspect.markcoroutinefunction`, which, applied to a sync function, makes it appear async to `inspect.iscoroutinefunction()`. * Docs: Don't upload CI artifacts (python#100330) * pythongh-89727: Fix os.walk RecursionError on deep trees (python#99803) Use a stack to implement os.walk iteratively instead of recursively to avoid hitting recursion limits on deeply nested trees. * pythongh-69929: re docs: Add more specific definition of \w (python#92015) Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> * pythongh-89051: Add ssl.OP_LEGACY_SERVER_CONNECT (python#93927) Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com> Co-authored-by: Christian Heimes <christian@python.org> Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com> Fixes python#89051 * pythongh-88211: Change lower-case and upper-case to match recommendations in imaplib docs (python#99625) * pythongh-100348: Fix ref cycle in `asyncio._SelectorSocketTransport` with `_read_ready_cb` (python#100349) * pythongh-99925: Fix inconsistency in `json.dumps()` error messages (pythonGH-99926) * Clarify that every thread has its own default context in contextvars (python#99246) * pythongh-99576: Fix cookiejar file that was not truncated for some classes (pythonGH-99616) Co-authored-by: Łukasz Langa <lukasz@langa.pl> * pythongh-100188: Reduce misses in BINARY_SUBSCR_(LIST/TUPLE)_INT (python#100189) Don't specialize if the index is negative. * pythongh-99991: improve docs on str.encode and bytes.decode (python#100198) Co-authored-by: C.A.M. Gerlach <CAM.Gerlach@Gerlach.CAM> * pythongh-91081: Add note on WeakKeyDictionary behavior when deleting a replaced entry (python#91499) Co-authored-by: Pieter Eendebak <P.T.eendebak@tudelft.nl> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> * pythongh-85267: Improvements to inspect.signature __text_signature__ handling (python#98796) This makes a couple related changes to inspect.signature's behaviour when parsing a signature from `__text_signature__`. First, `inspect.signature` is documented as only raising ValueError or TypeError. However, in some cases, we could raise RuntimeError. This PR changes that, thereby fixing python#83685. (Note that the new ValueErrors in RewriteSymbolics are caught and then reraised with a message) Second, `inspect.signature` could randomly drop parameters that it didn't understand (corresponding to `return None` in the `p` function). This is the core issue in python#85267. I think this is very surprising behaviour and it seems better to fail outright. Third, adding this new failure broke a couple tests. To fix them (and to e.g. allow `inspect.signature(select.epoll.register)` as in python#85267), I add constant folding of a couple binary operations to RewriteSymbolics. (There's some discussion of making signature expression evaluation arbitrary powerful in python#68155. I think that's out of scope. The additional constant folding here is pretty straightforward, useful, and not much of a slippery slope) Fourth, while python#85267 is incorrect about the cause of the issue, it turns out if you had consecutive newlines in __text_signature__, you'd get `tokenize.TokenError`. Finally, the `if name is invalid:` code path was dead, since `parse_name` never returned `invalid`. * pythonGH-100363: Speed up `asyncio.get_running_loop` (python#100364) * pythonGH-100133: fix `asyncio` subprocess losing `stderr` and `stdout` output (python#100154) * pythongh-100374: Fixed a bug in socket.getfqdn() (pythongh-100375) * pythongh-100129: Add tests for pickling all builtin types and functions (pythonGH-100142) * Remove unused variable from `dis._find_imports` (python#100396) * pythongh-78878: Fix crash when creating an instance of `_ctypes.CField` (python#14837) * pythonGH-69564: Clarify use of octal format of mode argument in help(os.chmod) (python#20621) Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com> * pythonGH-99554: Pack location tables more effectively (pythonGH-99556) * Correct typo in typing.py (python#100423) In the docstring of `ParamSpec`, the name of `P = ParamSpec('P')` was mistakenly written as `'T'`. * pythongh-99761: Add `_PyLong_IsPositiveSingleDigit` function to check for single digit integers (python#100064) * pythonGH-99770: Make the correct call specialization fail kind show up in the stats (pythonGH-99771) * pythongh-78997: fix bad rebase of moved test file (python#100424) * pythongh-100344: Add C implementation for `asyncio.current_task` (python#100345) Co-authored-by: pranavtbhat * pythonGH-99554: Trim trailing whitespace (pythonGH-100435) Automerge-Triggered-By: GH:brandtbucher * pythongh-85432: Harmonise parameter names between C and pure-Python implementations of `datetime.time.strftime`, `datetime.datetime.fromtimestamp` (python#99993) * pythongh-57762: fix misleading tkinter.Tk docstring (python#98837) Mentioned as a desired change by terryjreedy on the corresponding issue, since Tk is not a subclass of Toplevel. * pythongh-48496: Added example and link to faq for UnboundLocalError in reference (python#93068) * Fix typo in 3.12 What's New (python#100449) * pythongh-76963: PEP3118 itemsize of an empty ctypes array should not be 0 (pythonGH-5576) The itemsize returned in a memoryview of a ctypes array is now computed from the item type, instead of dividing the total size by the length and assuming that the length is not zero. * pythonGH-100459: fix copy-paste errors in specialization stats (pythonGH-100460) * pythongh-99110: Initialize `frame->previous` in init_frame to fix segmentation fault when accessing `frame.f_back` (python#100182) * pythongh-98712: Clarify "readonly bytes-like object" semantics in C arg-parsing docs (python#98710) * pythongh-92216: improve performance of `hasattr` for type objects (pythonGH-99979) * pythongh-100288: Specialise LOAD_ATTR_METHOD for managed dictionaries (pythonGH-100289) * Revert "pythongh-100288: Specialise LOAD_ATTR_METHOD for managed dictionaries (pythonGH-100289)" (python#100468) This reverts commit c3c7848. * pythongh-94155: Reduce hash collisions for code objects (python#100183) * Uses a better hashing algorithm to get better dispersion and remove commutativity. * Incorporates `co_firstlineno`, `Py_SIZE(co)`, and bytecode instructions. * This is now the entire set of criteria used in `code_richcompare`, except for `_PyCode_ConstantKey` (which would incorporate the types of `co_consts` rather than just their values). * pythongh-83076: 3.8x speed improvement in (Async)Mock instantiation (python#100252) * pythongh-99482: remove `jython` compatibility parts from stdlib and tests (python#99484) * bpo-40447: accept all path-like objects in compileall.compile_file (python#19883) Signed-off-by: Filipe Laíns <lains@archlinux.org> Signed-off-by: Filipe Laíns <lains@riseup.net> Co-authored-by: Irit Katriel <1055913+iritkatriel@users.noreply.github.com> Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com> * pythonGH-100425: Improve accuracy of builtin sum() for float inputs (pythonGH-100426) * pythongh-68320, pythongh-88302 - Allow for private `pathlib.Path` subclassing (pythonGH-31691) Users may wish to define subclasses of `pathlib.Path` to add or modify existing methods. Before this change, attempting to instantiate a subclass raised an exception like: AttributeError: type object 'PPath' has no attribute '_flavour' Previously the `_flavour` attribute was assigned as follows: PurePath._flavour = xxx not set!! xxx PurePosixPath._flavour = _PosixFlavour() PureWindowsPath._flavour = _WindowsFlavour() This change replaces it with a `_pathmod` attribute, set as follows: PurePath._pathmod = os.path PurePosixPath._pathmod = posixpath PureWindowsPath._pathmod = ntpath Functionality from `_PosixFlavour` and `_WindowsFlavour` is moved into `PurePath` as underscored-prefixed classmethods. Flavours are removed. Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com> Co-authored-by: Brett Cannon <brett@python.org> Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com> Co-authored-by: Eryk Sun <eryksun@gmail.com> * pythongh-99947: Ensure unreported errors are chained for SystemError during import (pythonGH-99946) * Add "strict" to dotproduct(). Add docstring. Factor-out common code. (pythonGH-100480) * pythongh-94808: improve test coverage of number formatting (python#99472) * pythongh-100454: Start running SSL tests with OpenSSL 3.1.0-beta1 (python#100456) * pythongh-100268: Add is_integer method to int (python#100439) This improves the lives of type annotation users of `float` - which type checkers implicitly treat as `int|float` because that is what most code actually wants. Before this change a `.is_integer()` method could not be assumed to exist on things annotated as `: float` due to the method not existing on both types. * pythongh-77771: Add enterabs example in sched (python#92716) Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com> * pythonGH-91166: Implement zero copy writes for `SelectorSocketTransport` in asyncio (python#31871) Co-authored-by: Guido van Rossum <gvanrossum@gmail.com> * pythonGH-91166: Implement zero copy writes for `SelectorSocketTransport` in asyncio (python#31871) Co-authored-by: Guido van Rossum <gvanrossum@gmail.com> * Misc Itertools recipe tweaks (pythonGH-100493) * pythongh-100357: Convert several functions in `bltinsmodule` to AC (python#100358) * Remove wrong comment about `repr` in `test_unicode` (python#100495) * pythongh-99908: Tutorial: Modernize the 'data-record class' example (python#100499) Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com> * pythongh-100474: Fix handling of dirs named index.html in http.server (pythonGH-100475) If you had a directory called index.html or index.htm within a directory, it would cause http.server to return a 404 Not Found error instead of the directory listing. This came about due to not checking that the index was a regular file. I have also added a test case for this situation. Automerge-Triggered-By: GH:merwok * pythongh-100287: Fix unittest.mock.seal with AsyncMock (python#100496) * pythongh-99535: Add test for inheritance of annotations and update documentation (python#99990) * pythongh-100428: Make float documentation more accurate (python#100437) Previously, the grammar did not accept `float("10")`. Also implement mdickinson's suggestion of removing the indirection. * [Minor PR] Quotes in documentation changed into code blocks (python#99536) Minor formatting fix in documentation Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com> * pythongh-100472: Fix docs claim that compileall parameters could be bytes (python#100473) * pythongh-100519: simplification to `eff_request_host` in cookiejar.py (python#99588) `IPV4_RE` includes a `.`, and the `.find(".") == -1` included here is already testing to make sure there's no dot, so this part of the expression is tautological. Instead use more modern `in` syntax to make it clear what the check is doing here. The simplified implementation more clearly matches the wording in RFC 2965. Co-authored-by: hauntsaninja <hauntsaninja@gmail.com> * pythongh-99308: Clarify re docs for byte pattern group names (python#99311) * pythongh-92446: Improve argparse choices docs; revert bad change to lzma docs (python#94627) Based on the definition of the collections.abc classes, it is more accurate to use "sequence" instead of "container" when describing argparse choices. A previous attempt at fixing this in python#92450 was mistaken; this PR reverts that change. Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com> * Fix name of removed `inspect.Signature.from_builtin` method in 3.11.0a2 changelog (python#100525) * pythongh-100520: Fix `rst` markup in `configparser` docstrings (python#100524) * pythongh-99509: Add `__class_getitem__` to `multiprocessing.queues.Queue` (python#99511) * pythongh-94603: micro optimize list.pop (pythongh-94604) * Remove `NoneType` redefinition from `clinic.py` (python#100551) * pythongh-100553: Improve accuracy of sqlite3.Row iter test (python#100555) * pythonGH-98831: Modernize a ton of simpler instructions (python#100545) * load_const and load_fast aren't families for now * Don't decref unmoved names * Modernize GET_ANEXT * Modernize GET_AWAITABLE * Modernize ASYNC_GEN_WRAP * Modernize YIELD_VALUE * Modernize POP_EXCEPT (in more than one way) * Modernize PREP_RERAISE_STAR * Modernize LOAD_ASSERTION_ERROR * Modernize LOAD_BUILD_CLASS * Modernize STORE_NAME * Modernize LOAD_NAME * Modernize LOAD_CLASSDEREF * Modernize LOAD_DEREF * Modernize STORE_DEREF * Modernize COPY_FREE_VARS (mark it as done) * Modernize LIST_TO_TUPLE * Modernize LIST_EXTEND * Modernize SET_UPDATE * Modernize SETUP_ANNOTATIONS * Modernize DICT_UPDATE * Modernize DICT_MERGE * Modernize MAP_ADD * Modernize IS_OP * Modernize CONTAINS_OP * Modernize CHECK_EXC_MATCH * Modernize IMPORT_NAME * Modernize IMPORT_STAR * Modernize IMPORT_FROM * Modernize JUMP_FORWARD (mark it as done) * Modernize JUMP_BACKWARD (mark it as done) Signed-off-by: Filipe Laíns <lains@archlinux.org> Signed-off-by: Filipe Laíns <lains@riseup.net> Co-authored-by: Jeremy Paige <ucodery@gmail.com> Co-authored-by: Carlton Gibson <carlton@noumenal.es> Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com> Co-authored-by: Jon Burdo <jon@jonburdo.com> Co-authored-by: Stanley <46876382+slateny@users.noreply.github.com> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> Co-authored-by: Thomas Grainger <tagrain@gmail.com> Co-authored-by: Brad Wolfe <brad.wolfe@gmail.com> Co-authored-by: Richard Kojedzinszky <rkojedzinszky@users.noreply.github.com> Co-authored-by: František Nesveda <fnesveda@users.noreply.github.com> Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com> Co-authored-by: Nikita Sobolev <mail@sobolevn.me> Co-authored-by: Łukasz Langa <lukasz@langa.pl> Co-authored-by: Dennis Sweeney <36520290+sweeneyde@users.noreply.github.com> Co-authored-by: Bisola Olasehinde <horlasehinde@gmail.com> Co-authored-by: C.A.M. Gerlach <CAM.Gerlach@Gerlach.CAM> Co-authored-by: Pieter Eendebak <P.T.eendebak@tudelft.nl> Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com> Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com> Co-authored-by: Dominic Socular <BBH@awsl.rip> Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> Co-authored-by: Hai Shi <shihai1992@gmail.com> Co-authored-by: amaajemyfren <32741226+amaajemyfren@users.noreply.github.com> Co-authored-by: Brandt Bucher <brandtbucher@microsoft.com> Co-authored-by: david-why <david_why@outlook.com> Co-authored-by: Pieter Eendebak <pieter.eendebak@gmail.com> Co-authored-by: penguin_wwy <940375606@qq.com> Co-authored-by: Eli Schwartz <eschwartz93@gmail.com> Co-authored-by: Itamar Ostricher <itamarost@gmail.com> Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com> Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: Irit Katriel <1055913+iritkatriel@users.noreply.github.com> Co-authored-by: Bill Fisher <william.w.fisher@gmail.com> Co-authored-by: Petr Viktorin <encukou@gmail.com> Co-authored-by: Ken Jin <kenjin@python.org> Co-authored-by: Carl Meyer <carl@oddbird.net> Co-authored-by: Filipe Laíns <lains@riseup.net> Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com> Co-authored-by: Barney Gale <barney.gale@gmail.com> Co-authored-by: Brett Cannon <brett@python.org> Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com> Co-authored-by: Eryk Sun <eryksun@gmail.com> Co-authored-by: Sebastian Berg <sebastianb@nvidia.com> Co-authored-by: Illia Volochii <illia.volochii@gmail.com> Co-authored-by: JosephSBoyle <48555120+JosephSBoyle@users.noreply.github.com> Co-authored-by: James Frost <git@frost.cx> Co-authored-by: MonadChains <monadchains@gmail.com> Co-authored-by: Bart Broere <mail@bartbroere.eu> Co-authored-by: Glyph <code@glyph.im> Co-authored-by: hauntsaninja <hauntsaninja@gmail.com> Co-authored-by: Ilya Kulakov <kulakov.ilya@gmail.com> Co-authored-by: Guy Yagev <yourlefthandman8@gmail.com> Co-authored-by: Jakub Kuczys <me@jacken.men>
This comment was marked as abuse.
This comment was marked as abuse.
Hi mzipay. Your code has a couple of problems:
Here's a fixed example: >>> from pathlib import Path
>>>
>>>
>>> class ExtPath(Path):
... def __init__(self, *args):
... self.extslot = 'this will disappear'
... super().__init__(*args)
...
>>>
>>> extpath = ExtPath('Spam/eggs.txt')
>>> extpath.extslot
'this will disappear'
>>> extpath.parent.extslot
'this will disappear' Hope that helps. If you have any specific criticisms or questions you have about pathlib's design I'll do my best to address them. But bear in mind you'll catch more flies with honey than vinegar ;) |
@mzipay Pep 20 is not "Python principles". It's poetry. https://mail.python.org/archives/list/python-dev@python.org/message/WG5VOX4R4WS5MHUR5NTF4IL3BKF4UI4Y/ |
@barneygale Apologies, (1) I was trying to simplify my sample code and didn't copy/paste it properly. (2) No "vinegar" intended, just trying to be succinct. (In fact I intentionally noted that "I love the idea of pathlib. I use it as often as I possibly can.")
Yes, I can be more specific: pathlib's First, though:
In my real-world use case, I am dealing with tens of thousands of Paths, so performance is a concern for me. Now back to the proposed fix (which doesn't work). Actually run this on 3.12.0a6:
You'll get Even if the super call is corrected, it still produces the unexpected result from my initial posting (granted I should've just posted the full example in the first place):
Running this results in an unexpected AttributeError:
Why does this happen? Take a close look at 3.12.0a6's pathlib.py, lines 302-317. Here you will find the PurePath._from_parts and PurePath._from_parsed_parts methods. These methods are used, from what I gather inspecting the code, to offer performance improvements by avoiding the need to re-parse the path segments. But they do so by bypassing Note the use of This means that any property or method of (a subclass of) Path that returns a new Path (like |
Seems this just got fixed in another issue (#85281) and merged a few days ago. Built 3.12.0a7, subclassing Path now appears to have expected behavior. |
Yep that's been a longstanding pathlib issue; it was difficult to address without regressing performance, and so there was a lot of preparatory work involved first. Glad to hear you have it working now! |
…calls to `os.path.normcase()` Use `re.IGNORECASE` to implement case-insensitive matching. This restores behaviour from before python#31691.
Users may wish to define subclasses of
pathlib.PurePath
andPath
to add or modify existing methods. Before this change, attempting to instantiate a subclass raised an exception like:Previously the
_flavour
attribute was assigned as follows:It's now set as follows:
Functionality from
_PosixFlavour
and_WindowsFlavour
is moved intoPurePath
as underscored-prefixed classmethods. Flavour classes are removed.A deeper dive into this patch can be read here: https://discuss.python.org/t/make-pathlib-extensible/3428/42
Fixes #68320 #88302