In the private pathlib ABCs, support write-only virtual filesystems by
making `WritablePath` inherit directly from `JoinablePath`, rather than
subclassing `ReadablePath`.
There are two complications:
- `ReadablePath.open()` applies to both reading and writing
- `ReadablePath.copy` is secretly an object that supports the *read* side
of copying, whereas `WritablePath.copy` is a different kind of object
supporting the *write* side
We untangle these as follow:
- A new `pathlib._abc.magic_open()` function replaces the `open()` method,
which is dropped from the ABCs but remains in `pathlib.Path`. The
function works like `io.open()`, but additionally accepts objects with
`__open_rb__()` or `__open_wb__()` methods as appropriate for the mode.
These new dunders are made abstract methods of `ReadablePath` and
`WritablePath` respectively. If the pathlib ABCs are made public, we
could consider blessing an "openable" protocol and supporting it in
`io.open()`, removing the need for `pathlib._abc.magic_open()`.
- `ReadablePath.copy` becomes a true method, whereas `WritablePath.copy` is
deleted. A new `ReadablePath._copy_reader` property provides a
`CopyReader` object, and similarly `WritablePath._copy_writer` is a
`CopyWriter` object. Once GH-125413 is resolved, we'll be able to move
the `CopyReader` functionality into `ReadablePath.info` and eliminate
`ReadablePath._copy_reader`.
Remove _PyInterpreterState_GetConfigCopy() and
_PyInterpreterState_SetConfig() private functions. PEP 741 "Python
Configuration C API" added a better public C API: PyConfig_Get() and
PyConfig_Set().
The same change was made, and for the same reason, by ``argparse`` back in
2017. The ``textwrap`` module is only used when printing help text, so most
invocations will never need it imported.
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
``gettext`` is often imported in programs that may not end up translating
anything. In fact, the ``struct`` module already has a delayed import when
parsing ``GNUTranslations`` to speed up the no ``.mo`` files case. The re module
is also used in the same situation, but behind a function chain only
called by ``GNUTranslations``.
Cache the compiled regex globally the first time it is used. The
finditer function is converted to a method call on the compiled
object which is slightly more efficient, and necessary for the
delayed re import.
Email generators using email.policy.default could incorrectly omit the
quote ('"') characters from a quoted-string during header refolding,
leading to invalid address headers and enabling header spoofing. This
change restores the quote characters on a bare-quoted-string as the
header is refolded, and escapes backslash and quote chars in the string.
