Improve performance of path construction by skipping the addition of the path anchor (`drive + root`) to the internal `_parts` list. Rename this attribute to `_tail` for clarity.
Fix an issue where `__new__()` and `__init__()` were not called on subclasses of `pathlib.PurePath` and `Path` in some circumstances.
Paths are now normalized on-demand. This speeds up path construction, `p.joinpath(q)`, and `p / q`.
Co-authored-by: Steve Dower <steve.dower@microsoft.com>
Use a stack to implement `pathlib.Path.walk()` iteratively instead of recursively to avoid hitting recursion limits on deeply nested trees.
Co-authored-by: Barney Gale <barney.gale@gmail.com>
Co-authored-by: Brett Cannon <brett@python.org>
The previous `_parse_args()` method pulled the `_parts` out of any supplied `PurePath` objects; these were subsequently joined in `_from_parts()` using `os.path.join()`. This is actually a slower form of joining than calling `fspath()` on the path object, because it doesn't take advantage of the fact that the contents of `_parts` is normalized!
This reduces the time taken to run `PurePath("foo", "bar")` by ~20%, and the time taken to run `PurePath(p, "cheese")`, where `p = PurePath("/foo", "bar", "baz")`, by ~40%.
Automerge-Triggered-By: GH:AlexWaygood
Fix a bug where `Path` takes and ignores `**kwargs` by adding to `PurePath` class `__init__` method which can take only positional arguments.
Automerge-Triggered-By: GH:brettcannon
Increase performance of the `absolute()` method by calling `os.getcwd()` directly, rather than using the `Path.cwd()` class method. This avoids constructing an extra `Path` object (and the parsing/normalization that comes with it).
Decrease performance of the `cwd()` class method by calling the `Path.absolute()` method, rather than using `os.getcwd()` directly. This involves constructing an extra `Path` object. We do this to maintain a longstanding pattern where `os` functions are called from only one place, which allows them to be more readily replaced by users. As `cwd()` is generally called at most once within user programs, it's a good bargain.
```shell
# before
$ ./python -m timeit -s 'from pathlib import Path; p = Path("foo", "bar")' 'p.absolute()'
50000 loops, best of 5: 9.04 usec per loop
# after
$ ./python -m timeit -s 'from pathlib import Path; p = Path("foo", "bar")' 'p.absolute()'
50000 loops, best of 5: 5.02 usec per loop
```
Automerge-Triggered-By: GH:AlexWaygood
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>
`relative_to()` now treats naked drive paths as relative. This brings its
behaviour in line with other parts of pathlib, and with `ntpath.relpath()`,
and so allows us to factor out the pathlib-specific implementation.
By default, :meth:`pathlib.PurePath.relative_to` doesn't deal with paths that are not a direct prefix of the other, raising an exception in that instance. This change adds a *walk_up* parameter that can be set to allow for using ``..`` to calculate the relative path.
example:
```
>>> p = PurePosixPath('/etc/passwd')
>>> p.relative_to('/etc')
PurePosixPath('passwd')
>>> p.relative_to('/usr')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "pathlib.py", line 940, in relative_to
raise ValueError(error_message.format(str(self), str(formatted)))
ValueError: '/etc/passwd' does not start with '/usr'
>>> p.relative_to('/usr', strict=False)
PurePosixPath('../etc/passwd')
```
https://bugs.python.org/issue40358
Automerge-Triggered-By: GH:brettcannon
Have pathlib use `os.path.join()` to join arguments to the `PurePath` initialiser, which fixes a minor bug when handling relative paths with drives.
Previously:
```python
>>> from pathlib import PureWindowsPath
>>> a = 'C:/a/b'
>>> b = 'C:x/y'
>>> PureWindowsPath(a, b)
PureWindowsPath('C:x/y')
```
Now:
```python
>>> PureWindowsPath(a, b)
PureWindowsPath('C:/a/b/x/y')
```
Have `pathlib.WindowsPath.is_mount()` call `ntpath.ismount()`. Previously it raised `NotImplementedError` unconditionally.
https://bugs.python.org/issue42777
When a `_PathParents` object has a drive or a root, the length of the
object is *one less* than than the length of `self._parts`, which resulted
in an off-by-one error when `path.parents[-n]` was fed through to
`self._parts[:-n - 1]`. In particular, `path.parents[-1]` was a malformed
path object with spooky properties.
This is addressed by adding `len(self)` to negative indices.
We could try to remedy this by taking a slice, but we then run into an issue where the empty string will match altsep on POSIX. That rabbit hole could keep getting deeper.
A proper fix for the original issue involves making pathlib's path normalisation more configurable - in this case we want to retain trailing slashes, but in other we might want to preserve `./` prefixes, or elide `../` segments when we're sure we won't encounter symlinks.
This reverts commit ea2f5bcda1.
Per Pitrou:
> The original intent for the “accessor” thing was to have a variant that did all accesses under a filesystem tree in a race condition-free way using openat and friends. It turned out to be much too hairy to actually implement, so was entirely abandoned, but the accessor abstraction was left there.
https://discuss.python.org/t/make-pathlib-extensible/3428/2
Accessors are:
- Lacking any internal purpose - '_NormalAccessor' is the only implementation
- Lacking any firm conceptual difference to `Path` objects themselves (inc. subclasses)
- Non-public, i.e. underscore prefixed - '_Accessor' and '_NormalAccessor'
- Unofficially used to implement customized `Path` objects, but once once [bpo-24132]() is addressed there will be a supported route for that.
This patch preserves all existing behaviour.
`pathlib.PureWindowsPath.is_reserved()` now identifies as reserved
filenames with trailing spaces or colons.
Co-authored-by: Barney Gale <barney.gale@foundry.com>
Co-authored-by: Eryk Sun <eryksun@gmail.com>
The argument order of `link_to()` is reversed compared to what one may expect, so:
a.link_to(b)
Might be expected to create *a* as a link to *b*, in fact it creates *b* as a link to *a*, making it function more like a "link from". This doesn't match `symlink_to()` nor the documentation and doesn't seem to be the original author's intent.
This PR deprecates `link_to()` and introduces `hardlink_to()`, which has the same argument order as `symlink_to()`.
Previously we had identical behaviour but only allowed accessors to override os.open(). This change allows the override to also construct the IO wrapper as well.
This makes `ntpath.expanduser()` match `pathlib.Path.expanduser()` in this regard, and is more in line with `posixpath.expanduser()`'s cautious approach.
Also remove the near-duplicate implementation of `expanduser()` in pathlib, and by doing so fix a bug where KeyError could be raised when expanding another user's home directory.
Barney Gale
Stanislav Zmiev
Yurii Karabas
Charles Machalow
Nikita Sobolev
domragusa
Stanislav Zmiev
Samuel Sloniker
Serhiy Storchaka
Gregory P. Smith
Eisuke Kawashima
andrei kulakov
Kevin Follstad
Steve Dower