On: Python Pip 20.3 Released with new resolver

[gjvc]

beware of zealot geeks bearing gifts. if your environment is currently working fine and you are only interested in running one version of python and perhaps experimenting with a later one then venv + pip is all you need, with some wrapper scripts as you say to make it ergonomic (to set the PYTHON* environment variables for your project, for example)

[dalemyers → gjvc]

The main reason I use Poetry is for its lockfile support. I've written about why lockfiles are good here: https://myers.io/2019/01/13/what-is-the-purpose-of-a-lock-fi...

[westurner → dalemyers]

Pip supports constraints files. https://pip.pypa.io/en/stable/user_guide/#constraints-files :

> Constraints files are requirements files that only control which version of a requirement is installed, not whether it is installed or not. Their syntax and contents is nearly identical to Requirements Files. There is one key difference: Including a package in a constraints file does not trigger installation of the package.

> Use a constraints file like so:

  python -m pip install -c constraints.txt

[jshen → westurner]

What does that command do? Does it install dependencies, or simply verify the versions of the installed dependencies?

[ptx → jshen]

It just gives you an error:

  ERROR: You must give at least one requirement to install (see "pip help install")

So it seems like a strange choice of usage example. You have to provide both requirements and constraints for it to do anything useful (applying the version constraints to the requirements and their dependencies).

[gjvc → dalemyers]

What does this do/have over files generated by "pip freeze" ?