Poetry has some stale dependencies because the use of develop = true packages. Poetry cannot figure out on its own that dependencies have been updated. How do I force Poetry to reinstall everything in its virtualenv to work around this issue?

These instructions are only for Linux/macOS for Windows Subsystem for Linux. For the Microsoft Windows shell, please use your own command-line knowledge to apply these instructions.

Recreating Poetry environment

To reinstall the packages for the Poetry environment in the current working directory (UNIX shell):

# Enter the current Poetry environment
poetry shell

# Remove the current environment
# as referred by path to Python interpreter 
poetry env remove $(which python)

# Reinstall from Poetry's cache
poetry install

Recreating Poetry environment manually

Do the following in the folder with pyproject.toml:

# Remove all the files of the current environment of the folder we are in
POETRY_LOCATION=`poetry env info -p` 
echo "Poetry is $POETRY_LOCATION"
rm -rf "$POETRY_LOCATION"

# Stop the current virtualenv if active or alternative use
# `exit` to exit from a Poetry shell session
deactivate

# Reactivate Poetry shell
poetry shell

# Install everything
poetry install

Recreating Poetry environment with different Python version

Poetry may refer to your installed Python version, so you might tell it to change its link to your python interpreter as well:

# Make Poetry to use python 3.9 from Homebrew, installed earlier
poetry env use `which python3.9`
poetry shell
python -V

Python 3.9.9

Kudos to this tip about removing the virtualenv.

Fixing damaged poetry command

If the poetry command itself is damaged and no longer runs, you can reinstall Poetry by:

which poetry

/Users/mikkoohtamaa/.poetry/bin/poetry

Then remove this and install:

# macOS
rm -rf /Users/mikkoohtamaa/.poetry
rm -rf  "/Users/$USER/Library/Application Support/pypoetry/venv"


# Linux
rm -rf ~/.local/share/pypoetry/

# Download and run Poetry install script
# If your curl is messed up you can try with --insecure flag
curl -sSL https://install.python-poetry.org/ | python3 - --force

Extreme painful issues

Sometimes Poetry may just fail to install after you have upgraded your Python e.g. with Homebrew. This might be to do with a fact who Poetry determines which Python version to use.

Errors you can see may include:

cat /Users/moo/poetry-installer-error-t0zfi7kb.log

dyld[6526]: Library not loaded: @loader_path/../Python
  Referenced from: <7295E559-55D4-3ACA-9820-D95D1F4AE151> /Users/moo/Library/Application Support/pypoetry/venv/bin/python3.10
  Reason: tried: '/Users/moo/Library/Application Support/pypoetry/venv/bin/../Python' (no such file), '/System/Volumes/Preboot/Cryptexes/OS@loader_path/../Python' (no such file), '/Users/moo/Library/Application Support/pypoetry/venv/bin/../Python' (no such file), '/usr/local/lib/Python' (no such file), '/usr/lib/Python' (no such file, not in dyld cache)

Traceback:

  File "<stdin>", line 923, in main
  File "<stdin>", line 562, in run

In this case, recommended approach is to switch away from Homebrew based Pythons and start using pyenv:

brew install pyenv

# Follow the instructions
pyenv init 

Then in a new shell install a specific Python version and check it is being used:

pyenv install 3.10
pyenv global 3.10
which python

Points to pyenv:

/Users/moo/.pyenv/shims/python

Now reinstall Poetry using a specific Python version and it should work:

curl -sSL https://install.python-poetry.org/ | python3.10 -