Refuse to guess what a user means when they initialise a pathlib ABC
without any positional arguments. In mainline pathlib it's normalised to
`.`, but in the ABCs this guess isn't appropriate; for example, the path
type may not represent the current directory as `.`, or may have no concept
of a "current directory" at all.
Apply pathlib's normalization and performance tuning in `pathlib.PurePath`, but not `pathlib._abc.PurePathBase`.
With this change, the pathlib ABCs do not normalize away alternate path separators, empty segments, or dot segments. A single string given to the initialiser will round-trip by default, i.e. `str(PurePathBase(my_string)) == my_string`. Implementors can set their own path domain-specific normalization scheme by overriding `__str__()`
Eliminating path normalization makes maintaining and caching the path's parts and string representation both optional and not very useful, so this commit moves the `_drv`, `_root`, `_tail_cached` and `_str` slots from `PurePathBase` to `PurePath`. Only `_raw_paths` and `_resolving` slots remain in `PurePathBase`. This frees the ABCs from the burden of some of pathlib's hardest-to-understand code.
Restore full battle-tested implementations of `PurePath.[is_]relative_to()`. These were recently split up in 3375dfe and a15a773.
In `PurePathBase`, add entirely new implementations based on `_stack`, which itself calls `pathmod.split()` repeatedly to disassemble a path. These new implementations preserve features like trailing slashes where possible, while still observing that a `..` segment cannot be added to traverse an empty or `.` segment in *walk_up* mode. They do not rely on `parents` nor `__eq__()`, nor do they spin up temporary path objects.
Unfortunately calling `pathmod.relpath()` isn't an option, as it calls `abspath()` and in turn `os.getcwd()`, which is impure.
Implement `parts` using `_stack`, which itself calls `pathmod.split()`
repeatedly. This avoids use of `_tail`, which will be moved to `PurePath`
shortly.
- Add `__slots__` to dummy path classes.
- Return namedtuple rather than `os.stat_result` from `DummyPath.stat()`.
- Reduce maximum symlink count in `DummyPathWithSymlinks.resolve()`.
Replace use of `_from_parsed_parts()` with `with_segments()` in
`PurePathBase.relative_to()`, and move the assignment of `_drv`, `_root`
and `_tail_cached` slots into `PurePath.relative_to()`.
Raise auditing events in `pathlib.Path.glob()`, `rglob()` and `walk()`,
but not in `pathlib._abc.PathBase` methods. Also move generation of a
deprecation warning into `pathlib.Path` so it gets the right stack level.
The `pathlib._abc` module will be made available as a PyPI backport
supporting Python 3.8+. The `warnings._deprecated()` function was only
added last year, and it's private from an external package perspective, so
here we switch to `warnings.warn()` instead.
Do not use the locale-specific default encoding in `PathBase.read_text()`
and `write_text()`. Locale settings shouldn't influence the operation of
these base classes, which are intended mostly for implementing rich paths
on *nonlocal* filesystems.
Change the value of `pathlib._abc.PurePathBase.pathmod` from `os.path` to
`posixpath`.
User subclasses of `PurePathBase` and `PathBase` previously used the host
OS's path syntax, e.g. backslashes as separators on Windows. This is wrong
in most use cases, and likely to catch developers out unless they test on
both Windows and non-Windows machines.
In this patch we change the default to POSIX syntax, regardless of OS. This
is somewhat arguable (why not make all aspects of syntax abstract and
individually configurable?) but an improvement all the same.
This change has no effect on `PurePath`, `Path`, nor their subclasses. Only
private APIs are affected.
`PurePathBase.__repr__()` produces a string like `MyPath('/foo')`. This
repr is incorrect/misleading when a subclass's `__init__()` method is
customized, which I expect to be the very common.
This commit moves the `__repr__()` method to `PurePath`, leaving
`PurePathBase` with the default `object` repr.
No user-facing changes because the `pathlib._abc` module remains private.
This was caused by 76929fdeeb, specifically its use of `super()` and its
packing/unpacking `*args`.
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Move `_PurePathBase` and `_PathBase` to a new `pathlib._abc` module, and
drop the underscores from the class names.
Tests are mostly left alone in this commit, but they'll be similarly split
in a subsequent commit.
The `pathlib._abc` module will be published as an independent PyPI package
(similar to how `zipfile._path` is published as `zipp`), to be refined
and stabilised prior to its possible addition to the standard library.
