=================
Process
-------
- ``pip freeze``, ``pip list``, and ``pip show`` no longer normalize underscore
(``_``) in distribution names to dash (``-``). This is a side effect of the
migration to ``importlib.metadata``, since the underscore-dash normalization
behavior is non-standard and specific to setuptools. This should not affect
other parts of pip (for example, when feeding the ``pip freeze`` result back
into ``pip install``) since pip internally performs standard PEP 503
normalization independently to setuptools.
Deprecations and Removals
-------------------------
- Git version parsing is now done with regular expression to prepare for the
pending upstream removal of non-PEP-440 version parsing logic. (`10117 <https://github.com/pypa/pip/issues/10117>`_)
- Re-enable the "Value for ... does not match" location warnings to field a new
round of feedback for the ``distutils``-``sysconfig`` transition. (`10151 <https://github.com/pypa/pip/issues/10151>`_)
- Remove deprecated ``--find-links`` option in ``pip freeze`` (`9069 <https://github.com/pypa/pip/issues/9069>`_)
Features
--------
- New resolver: Loosen URL comparison logic when checking for direct URL reference
equivalency. The logic includes the following notable characteristics:
* The authentication part of the URL is explicitly ignored.
* Most of the fragment part, including ``egg=``, is explicitly ignored. Only
``subdirectory=`` and hash values (e.g. ``sha256=``) are kept.
* The query part of the URL is parsed to allow ordering differences. (`10002 <https://github.com/pypa/pip/issues/10002>`_)
- Support TOML v1.0.0 syntax in ``pyproject.toml``. (`10034 <https://github.com/pypa/pip/issues/10034>`_)
- Added a warning message for errors caused due to Long Paths being disabled on Windows. (`10045 <https://github.com/pypa/pip/issues/10045>`_)
- Change the encoding of log file from default text encoding to UTF-8. (`10071 <https://github.com/pypa/pip/issues/10071>`_)
- Log the resolved commit SHA when installing a package from a Git repository. (`10149 <https://github.com/pypa/pip/issues/10149>`_)
- Add a warning when passing an invalid requirement to ``pip uninstall``. (`4958 <https://github.com/pypa/pip/issues/4958>`_)
- Add new subcommand ``pip index`` used to interact with indexes, and implement
``pip index version`` to list available versions of a package. (`7975 <https://github.com/pypa/pip/issues/7975>`_)
- When pip is asked to uninstall a project without the dist-info/RECORD file
it will no longer traceback with FileNotFoundError,
but it will provide a better error message instead, such as::
ERROR: Cannot uninstall foobar 0.1, RECORD file not found. You might be able to recover from this via: 'pip install --force-reinstall --no-deps foobar==0.1'.
When dist-info/INSTALLER is present and contains some useful information, the info is included in the error message instead::
ERROR: Cannot uninstall foobar 0.1, RECORD file not found. Hint: The package was installed by rpm.
(`8954 <https://github.com/pypa/pip/issues/8954>`_)
- Add an additional level of verbosity. ``--verbose`` (and the shorthand ``-v``) now
contains significantly less output, and users that need complete full debug-level output
should pass it twice (``--verbose --verbose`` or ``-vv``). (`9450 <https://github.com/pypa/pip/issues/9450>`_)
- New resolver: The order of dependencies resolution has been tweaked to traverse
the dependency graph in a more breadth-first approach. (`9455 <https://github.com/pypa/pip/issues/9455>`_)
- Make "yes" the default choice in ``pip uninstall``'s prompt. (`9686 <https://github.com/pypa/pip/issues/9686>`_)
- Add a special error message when users forget the ``-r`` flag when installing. (`9915 <https://github.com/pypa/pip/issues/9915>`_)
- New resolver: A distribution's ``Requires-Python`` metadata is now checked
before its Python dependencies. This makes the resolver fail quicker when
there's an interpreter version conflict. (`9925 <https://github.com/pypa/pip/issues/9925>`_)
- Suppress "not on PATH" warning when ``--prefix`` is given. (`9931 <https://github.com/pypa/pip/issues/9931>`_)
- Include ``rustc`` version in pip's ``User-Agent``, when the system has ``rustc``. (`9987 <https://github.com/pypa/pip/issues/9987>`_)
Bug Fixes
---------
- Update vendored six to 1.16.0 and urllib3 to 1.26.5 (`10043 <https://github.com/pypa/pip/issues/10043>`_)
- Correctly allow PEP 517 projects to be detected without warnings in ``pip freeze``. (`10080 <https://github.com/pypa/pip/issues/10080>`_)
- Strip leading slash from a ``file://`` URL built from an path with the Windows
drive notation. This fixes bugs where the ``file://`` URL cannot be correctly
used as requirement, constraint, or index URLs on Windows. (`10115 <https://github.com/pypa/pip/issues/10115>`_)
- New resolver: URL comparison logic now treats ``file://localhost/`` and
``file:///`` as equivalent to conform to RFC 8089. (`10162 <https://github.com/pypa/pip/issues/10162>`_)
- Prefer credentials from the URL over the previously-obtained credentials from URLs of the same domain, so it is possible to use different credentials on the same index server for different ``--extra-index-url`` options. (`3931 <https://github.com/pypa/pip/issues/3931>`_)
- Fix extraction of files with utf-8 encoded paths from tars. (`7667 <https://github.com/pypa/pip/issues/7667>`_)
- Skip distutils configuration parsing on encoding errors. (`8931 <https://github.com/pypa/pip/issues/8931>`_)
- New resolver: Detect an unnamed requirement is user-specified (by building its
metadata for the project name) so it can be correctly ordered in the resolver. (`9204 <https://github.com/pypa/pip/issues/9204>`_)
- Fix :ref:`pip freeze` to output packages :ref:`installed from git <vcs support>`
in the correct ``git+protocol://git.example.com/MyProjectegg=MyProject`` format
rather than the old and no longer supported ``git+git`` format. (`9822 <https://github.com/pypa/pip/issues/9822>`_)
- Fix warnings about install scheme selection for Python framework builds
distributed by Apple's Command Line Tools. (`9844 <https://github.com/pypa/pip/issues/9844>`_)
- Relax interpreter detection to quelch a location mismatch warning where PyPy
is deliberately breaking backwards compatibility. (`9845 <https://github.com/pypa/pip/issues/9845>`_)
Vendored Libraries
------------------
- Upgrade certifi to 2021.05.30.
- Upgrade idna to 3.2.
- Upgrade packaging to 21.0
- Upgrade requests to 2.26.0.
- Upgrade resolvelib to 0.7.1.
- Upgrade urllib3 to 1.26.6.