The problem originates when I start by cloning a git project that uses pipenv, so it has a Pipfile + Pipfile.lock. I want to use a virtual environment with the project so I run pipenv shell. I now have a virtual environment created and I am inside the virtual environment. The project obviously has a lot of dependencies (listed in the Pipfile). I don't want to have to go through the list in the Pipfile one by one and install them using pipenv install <package_name>. Is there a pipenv/pip command that installs all the packages from a Pipfile I already have? Or maybe I need to set up the environment differently than running pipenv shell?
The proper answer to this question is that pipenv install or pipenv install --dev (if there are dev dependencies) should be ran. That will install all the dependencies in the Pipfile. Putting the dependencies into a requirements.txt and then using pip will work but is not really necessary. The whole point of using pipenv for most people is to avoid the need to manage a requirements.txt or to use pip.
EDIT: if the virtualenv is already activated, you can also use pipenv sync or pipenv sync --dev for the same effect.