ImportError: cannot import name 'PackageFinder'

Question

after updating everything in conda, pip can't install anything

conda update -n base conda
conda update --all

when install or upgrade anything, this error is show

   $ pip install --upgrade HDF5
Traceback (most recent call last):
  File "C:\ProgramData\Anaconda3\Scripts\pip-script.py", line 10, in <module>
    sys.exit(main())
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\_internal\main.py", line 45, in main
    command = create_command(cmd_name, isolated=("--isolated" in cmd_args))
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\_internal\commands\__init__.py", line 96, in create_command
    module = importlib.import_module(module_path)
  File "C:\ProgramData\Anaconda3\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\_internal\commands\install.py", line 23, in <module>
    from pip._internal.cli.req_command import RequirementCommand
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\_internal\cli\req_command.py", line 17, in <module>
    from pip._internal.index import PackageFinder
ImportError: cannot import name 'PackageFinder'

any help please. thank you.

Answer 1

It seems that this works. Reinstall the latest version of pip:

$ curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py && python get-pip.py

When you’re done, delete the installation script:

$ rm get-pip.py

Answer 2

Solved this by manually updating: Command Line Tools for XCode.

From the terminal run: softwareupdate --list which produces a list of available updates.

Wait a bit for a list to display (won't take very long). And look for the "* Label:" under Software Update found the following new or updated software:

It should say something like: * Label: Command Line Tools for Xcode-13.0

Then simply run: softwareupdate -i "Command Line Tools for Xcode-13.0" and replace the text in the brackets with the Label from the previous output. This will then install the updates and the fix for python3.

Then run: pip3 --version and it should work.

Answer 3

This happens usually, if you try to reinstall pip and the distro's pre-packaged version mismatches the previously installed version (e.g. 19.0.3 (packaged) vs 20.0.2 (installed) at time of writing).

Removing the /path/to/site-packages/pip* directories is a simple (yet safe) solution.

Here's a little bash script for the system installed version (thus requires sudo):

#!/bin/bash
set -e

 # Set PY_MAJ and PY_MIN with your own python "major.minor" version
 # Example for python 3.8
 # PY_MAJ='3'
 # PY_MIN='8'
 cd /usr/lib/python${PY_MAJ}.${PY_MIN}/site-packages/ \
 && rm -rf pip/ \
 && rm -rf pip-*/ \
 ; cd -

Note for virtual environments: Basically the same is valid for venv's. Only difference is the "site-packages" directory location.