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Brian #1: Do you really need a virtualenv?

• Frost Ming doesn’t think so, based on the article You don’t really need a virtualenv
• The link slug is “introducing-pdm”, which I think would be a better title, but the first did work to get people to talk about it. Also, “Try PEP 582 today” may have been appropriate.
• Teaching new people is a problem:
• Telling them to first type python -m venv venv
• Then type source venv/bin/activate or . venv/bin/activate
• Unless you’re on windows, then type venv\scripts\activate.bat
• Then type pip install -r requirements.txt
• Yeah. It’s not pretty, not fun, and good luck not having anyone ask questions about why this is necessary.
• Also the Python version is specified in the venv. So if you upgrade Python versions, what happens to existing venvs?
• The article also discusses levels of venvs, and global tools that maybe you want not tied to each venv. But we have pipx for that, so I don’t think that’s a real issue.
• Enter PEP 582, still in draft mode.
• Instead of a venv directory, your project has a __pypackage__ directory. If you python -m pip install in your project directory, stuff just goes there instead of to the global Python.
• So it kinda acts like a venv for local packages, it just doesn’t include local copies of the Python executables, and such.
• This is probably a horrible description of 582, but oh well. Something like that.
• pdm supports 582 today
• PDM stands for Python Development Master
• “It installs and manages packages in a similar way to npm that doesn’t need to create a virtualenv at all!”
• Has a workflow that reminds me of Poetry, but doesn’t use a venv, uses a package directory instead.
• Conclusion:
• Huge props to Frost for this. It’s cool to see a tool that supports 582 and glimpse a possible Python future.
• However, this doesn’t solve the “teaching Python” problem. The setup is more complex than venv.
• I’m personally sticking with venv, well virtualenv, until (and if) 582 is supported by Python and pip.

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