** Description changed: [Impact] Python 2.7 support is ending upstream. Python libraries are dropping 2.7 support, in response to this. One of the ways that legacy applications & libraries can stay installable is that Python packages can declare Requires-Python >= 3 (or similar). https://packaging.python.org/guides/dropping-older-python-versions/ The version of pip in Xenial is *just* too old to support this, so it happily downloads and installs libraries that declare incompatibility with Python 2.7. setuptools 45.0.0 was released earlier this year, dropping support for Python 2.7. It's one of the core packages installed by virtualenv. Since it was released, virtualenv has been installing it, and then been unable to build C extensions. [Test Case] + + # sudo apt install python virtualenv python-pip python3-pip These should install setuptools older than 45, that still works with Python 2.7: $ pip install --user setuptools $ python -c 'import setuptools; print(setuptools.__version__)' 44.0.0 $ virtualenv -v -p python testve $ testve/bin/python -c 'import setuptools; print(setuptools.__version__)' 44.0.0 Clean up, assuming you don't have anything important in there: $ rm -rf ~/.local/{bin,lib} testve These should install setuptools newer than 45, which is compatible with Python 3.5: $ pip3 install --user setuptools $ python3 -c 'import setuptools; print(setuptools.__version__)' 45.2.0 $ virtualenv -v -p python3 testve $ testve/bin/python -c 'import setuptools; print(setuptools.__version__)' 45.2.0 $ rm -rf ~/.local/{bin,lib} testve [Regression Potential] Changing behaviour of core tools always comes with a risk. And pip is at the centre of the python ecosystem. However, this is an attempt to fix a post-release regression. The patch comes from pip's git history. This code has changed since then, so it's not known to be bug-free. From NEWS spelunking, these changes seem related, but are not backported in this SRU, to keep it minimal: From 19.2: - * Update ``pip download`` to respect the given ``--python-version`` when - checking ``"Requires-Python"``. + * Update ``pip download`` to respect the given ``--python-version`` when + checking ``"Requires-Python"``. https://github.com/pypa/pip/issues/5369 * Fix ``pip install`` to respect ``--ignore-requires-python`` when - evaluating links. + evaluating links. https://github.com/pypa/pip/issues/6371 From 9.0.0: * Raise when Requires-Python do not match the running version and add - ``--ignore-requires-python`` option as escape hatch. + ``--ignore-requires-python`` option as escape hatch. https://github.com/pypa/pip/issues/3846 [Other Info] User Bug: https://github.com/pypa/packaging-problems/issues/325 PEP 503 - Simple Repository API: https://www.python.org/dev/peps/pep-0503/ PEP 345 - Metadata for Python Software Packages 1.2: https://www.python.org/dev/peps/pep-0345/
** Description changed: [Impact] Python 2.7 support is ending upstream. Python libraries are dropping 2.7 support, in response to this. One of the ways that legacy applications & libraries can stay installable is that Python packages can declare Requires-Python >= 3 (or similar). https://packaging.python.org/guides/dropping-older-python-versions/ The version of pip in Xenial is *just* too old to support this, so it happily downloads and installs libraries that declare incompatibility with Python 2.7. setuptools 45.0.0 was released earlier this year, dropping support for Python 2.7. It's one of the core packages installed by virtualenv. Since it was released, virtualenv has been installing it, and then been unable to build C extensions. [Test Case] - # sudo apt install python virtualenv python-pip python3-pip + # apt install python virtualenv python-pip python3-pip These should install setuptools older than 45, that still works with Python 2.7: $ pip install --user setuptools $ python -c 'import setuptools; print(setuptools.__version__)' 44.0.0 $ virtualenv -v -p python testve $ testve/bin/python -c 'import setuptools; print(setuptools.__version__)' 44.0.0 Clean up, assuming you don't have anything important in there: $ rm -rf ~/.local/{bin,lib} testve These should install setuptools newer than 45, which is compatible with Python 3.5: $ pip3 install --user setuptools $ python3 -c 'import setuptools; print(setuptools.__version__)' 45.2.0 $ virtualenv -v -p python3 testve $ testve/bin/python -c 'import setuptools; print(setuptools.__version__)' 45.2.0 $ rm -rf ~/.local/{bin,lib} testve [Regression Potential] Changing behaviour of core tools always comes with a risk. And pip is at the centre of the python ecosystem. However, this is an attempt to fix a post-release regression. The patch comes from pip's git history. This code has changed since then, so it's not known to be bug-free. From NEWS spelunking, these changes seem related, but are not backported in this SRU, to keep it minimal: From 19.2: * Update ``pip download`` to respect the given ``--python-version`` when checking ``"Requires-Python"``. https://github.com/pypa/pip/issues/5369 * Fix ``pip install`` to respect ``--ignore-requires-python`` when evaluating links. https://github.com/pypa/pip/issues/6371 From 9.0.0: * Raise when Requires-Python do not match the running version and add ``--ignore-requires-python`` option as escape hatch. https://github.com/pypa/pip/issues/3846 [Other Info] User Bug: https://github.com/pypa/packaging-problems/issues/325 PEP 503 - Simple Repository API: https://www.python.org/dev/peps/pep-0503/ PEP 345 - Metadata for Python Software Packages 1.2: https://www.python.org/dev/peps/pep-0345/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1864766 Title: [SRU] pip in xenial is installing packages incompatible with Python 2.7 (and those are becoming common) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/python-pip/+bug/1864766/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
