Answer: they don’t
(Seriously, I’ve gotten so fed up with Python package management that I just use CondaPkg.jl, which uses Julia’s package manager to take care of Python packages. It is just so much cleaner and easier to use than anything in Python.)
I hate python package management - I really do. But I've never actually had a problem with virtual environments, and I think it's because I just use virtualenv directly (rather than conda or whatever else).
I have these aliases in my .bashrc, and I can't remember the last time I had a major issue.
alias venv='rm -rf ./venv && virtualenv venv && source ./venv/bin/activate'
alias vact='source ./venv/bin/activate'
alias pinstall='source ./venv/bin/activate && pip install . && pip install -r ./requirements.txt && pip install ./test_requirements.txt'
I don't have all the fancy features, like automatically activating the virtualenv when I cd into the directory, but I've always found those to be a bigger headache than they are worth. And if I ever run into some incompatibility or duplicate library or something, I blow away the old venv and start fresh. It's a good excuse to get up and make a cup of tea.
> virtualenv venv
That would be python2, in 3 it's "python -m venv venv" (first venv is package to run, second is directory to put it in)
Otherwise yeah, it's the same and I also use it manually. Never had any problems.