ensurepip optionally installs or upgrades 'pip' and 'setuptools' using
the version of those modules bundled with Python. The internal PIP
installation routine by default temporarily uses its cache, if it
exists. This is undesirable as Python builds and installations may be
independent of the user running the build, whilst PIP cache location
is dependent on the user's environment and outside of the build
environment.
At the same time, there's no value in using the cache while installing
bundled modules.
This change disables PIP caching when used in ensurepip.
The ensurepip module now invokes pip via the runpy module.
Hence it is no longer tightly coupled with the internal API of the bundled
pip version, allowing easier updates to a newer pip version both
internally and for distributors.
This way, any changes to the internal pip API won't mean ensurepip needs to be
changed as well. Also, distributors can update their pip wheels independent on
CPython release schedule.
Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>
Co-Authored-By: Miro Hrončok <miro@hroncok.cz>
* Add a space to ensurepip's --altinstall option
* Add periods to the arguments of ensurepip that didn't have it
This makes --help for all optional arguments consistent and also makes it
consistent with pip --help.
Ensure that the uninstall helper for Windows passes the proper
flags to pip to prevent it from checking PyPI if the pip that
we're currently attempting to uninstall is the latest verison.
The 3.4rc2 Windows uninstaller would fail if pip had been updated
to a version that didn't match the version installed by ensurepip.
This skip is no longer treated as an error, so an updated pip ends
up being handled like any other pip installed package and is left
alone by the CPython uninstaller.
ensurepip now sets PIP_CONFIG_FILE to os.devnull before
import pip from the wheel file. This also ensures venv
ignores the default settings when bootstrapping pip.
