Error after upgrading pip: cannot import name 'main'

Leveraging virtual environments

Should you run into trouble when upgrading pip, leveraging virtual environments can be your best ally. Virtualenv enables you to create distinct environments for various projects, thereby eliminating system-wide conflicts that may lead to the 'main' import error.

To initiate a virtual environment:

python3 -m venv myenv                                    # "myenv" is an environment you're creating
source myenv/bin/activate    # Unix-like systems         # Step into another dimension, Unix-style!
myenv\Scripts\activate       # Windows                   # Step into another dimension, Windows-style!
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In an active environment, you can upgrade pip without meddling with the system pip:

python -m pip install --upgrade pip                   # A world where 'pip' upgrades never turn sour! 🍋🍬
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Recovering a broken pip3

An attempted system-wide upgrade can sometimes leave pip3 in ruins. No worries, you can restore pip3 using this command:

sudo python3 -m pip uninstall pip && sudo apt install python3-pip --reinstall    # It's resurrection time! 🙌
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This command first exorcises the wrongdoer pip, then reinstalls the python3-pip package. After recovery, avoid further threat by focusing on using virtual environments instead of upgrading system pip.

Shifting to safe practices

To side-step permission issues and package clashes, steer clear from the 'sudo pip' command and system-wide installs. Instead, lean towards APT for system-wide Python packages installation, or better yet, stick with virtual environments.

For added convenience, consider setting up aliases in .bashrc:

alias pipupg='python -m pip install --upgrade pip'    # Make it short, silly!
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When things get more complicated, pair pyenv with virtualenv to juggle multiple Python versions safely. For system-wide Python version upgrades, use:

sudo apt-get install python3.x    # Substitute 'x' with your desired version number
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Familiarize yourself with pip internals

With the advent of Pip 10.x, its internal workings underwent major restructuring, causing potential import errors post-upgrade. If things go south, a hasty fix can be made by tweaking the /usr/bin/pip file:

Replace the line with:

from pip import __main__     # The old neighborhood
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with:

from pip._internal import main    # The new digs
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and change:

sys.exit(main())    # The old exit route
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to:

sys.exit(__main__._main())    # The scenic route 🌳🏞️
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Treat this file editing hack as a nuclear option and use only when it's the end of the world!

Consult the oracles when all else fails

On occasion when pip is still playing hardball, seek guidance from the package maintainer or check out the discussions at pip's issue tracker for any known issues or quick fixes.

In the times of persistent distress, try these:

1. Probe for open issues on pip’s GitHub repository.
2. Delve into discussion forums for possible solutions.
3. Ponder on alternatives like Anaconda for managing complex package dependencies.

Remember, best practices and understanding the tools are keys to development mastery.