pip issues using 3.7.6 build

[mnsanandres]

Initial tests with the python interpreter looks OK but for some reason, pip doesn't seem to work:

[root@bfat3-fedora-1 bin]# ./pip3 install distro
-bash: ./pip3: /build/out/python/install/bin/python3: bad interpreter: No such file or directory
[root@bfat3-fedora-1 bin]# ./python3 -m pip install distro
ERROR: Could not install packages due to an EnvironmentError: Dynamic loading not supported

I'm not sure why the absolute path of I suppose the original build location is referenced.

[indygreg]

Is this a regression?

[mnsanandres]

Not sure by that but what I did is download the latest from https://github.com/indygreg/python-build-standalone/releases/tag/20200216, extract the contents and run pip from there.

Specifically, I used cpython-3.7.6-linux64-musl-20200216T2355.tar.zst.

[indygreg]

Are you running the musl distribution? I would only expect Dynamic loading not supported to fail in a fully statically linked binary. Assuming yes, the question then becomes: what is attempting to load a shared library when running pip install?

FWIW lots of code in Python assumes Python is built in a very specific way and that a libpython exists. The statically linked builds that python-build-standalone produces invalidate these assumptions. I've had to employ various patches to various components to get CPython to work in a statically linked environment. It is a royal pain to support and I wouldn't at all be surprised if something regressed in Python 3.7.6 or in a newer version of pip.

[mnsanandres]

Yes I am using the musl distribution. Running pip in verbose gives me:

There was an error checking the latest version of pip
Traceback (most recent call last):
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/self_outdated_check.py", line 207, in pip_self_version_check
    best_candidate = finder.find_best_candidate("pip").best_candidate
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/index/package_finder.py", line 881, in find_best_candidate
    candidates = self.find_all_candidates(project_name)
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/index/package_finder.py", line 826, in find_all_candidates
    project_url, link_evaluator=link_evaluator,
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/index/package_finder.py", line 799, in process_project_url
    links=page_links,
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/index/package_finder.py", line 779, in evaluate_links
    candidate = self.get_install_candidate(link_evaluator, link)
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/index/package_finder.py", line 758, in get_install_candidate
    is_candidate, result = link_evaluator.evaluate_link(link)
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/index/package_finder.py", line 195, in evaluate_link
    supported_tags = self._target_python.get_tags()
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/models/target_python.py", line 103, in get_tags
    impl=self.implementation,
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_internal/pep425tags.py", line 148, in get_supported
    platforms=platforms,
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_vendor/packaging/tags.py", line 242, in cpython_tags
    platforms = list(platforms or _platform_tags())
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_vendor/packaging/tags.py", line 657, in _linux_platforms
    if _is_manylinux_compatible(name, glibc_version):
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_vendor/packaging/tags.py", line 422, in _is_manylinux_compatible
    return _have_compatible_glibc(*glibc_version)
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_vendor/packaging/tags.py", line 512, in _have_compatible_glibc
    version_str = _glibc_version_string()
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_vendor/packaging/tags.py", line 428, in _glibc_version_string
    return _glibc_version_string_confstr() or _glibc_version_string_ctypes()
  File "/opt/python/install/lib/python3.7/site-packages/pip-20.0.2-py3.7.egg/pip/_vendor/packaging/tags.py", line 469, in _glibc_version_string_ctypes
    process_namespace = ctypes.CDLL(None)  # type: ignore
  File "/opt/python/install/lib/python3.7/ctypes/__init__.py", line 364, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: Dynamic loading not supported

Not sure what specific library is being loaded but I'll see if I can trace that.

[indygreg]

Thanks for the stack trace. This code looks very similar to other code I'm having to patch to work around ctypes usage. I think I fixed one call site in the upgraded setuptools but missed this one. This is definitely a regression from the pip 20.0.2 upgrade in the latest release...

Oh, the bugs you find when you are building Python differently from the rest of the world...

[mnsanandres]

Glad to share. But going to back to first command execution:

[root@bfat3-fedora-1 bin]# ./pip3 install distro
-bash: ./pip3: /build/out/python/install/bin/python3: bad interpreter: No such file or directory

Any idea why that /build/out/... is used when running the pip3 binary (instead of running it as module)?

[mnsanandres]

Thank you for the fast release, I can confirm that it now works. Any thoughts on my last question though?

[mnsanandres]

Upon inspection of the pip "binary", it looks like it is just a python script with no extension. Changing the path for python in shebang line would fix the issue.