I suppose it does doe that, so does this though:

    with codecs.open('requirements.txt') as f:
        requirements = f.read().splitlines()
    ...
    install_requires=requirements,

I don't think it's worth the dependency. But perhaps for others it is.

That works for simple use cases but it is not robust.

In case anyone sees this, at a minimum you need to use

  from pip.req import parse_requirements
  parse_requirements('path/to/requirements.txt')

to be safe here.

What if the user doesn't have pip installed? This is before we've installed the requirements, so we shouldn't be assuming anything outside the stdlib.

if I'm not mistaken, requirements are parsed out to be installed before installing the desired package, so that should be fine

Isn't that paradoxical? That code is for parsing requirements and those requirements can't be parsed until initial pre-requirements (pip, in this case) are installed.

sorta

from my understanding, when you build the package, your computer extracts the relevant required packages, and sends up that data to pypi, which then in turn sends that data back to users when they install

At least thats how I think it works

I think you may be misunderstanding the problem being discussed. The code that uses pip will crash if pip is not already installed. There is no way to parse and satisfy the dependency on pip, because the author chose to import pip as a library.

pip being a dependency is defined at upload time, it is parsed by the creator of the package, not the consumer, afaik

if you used any other package manager, it would need to resolve dependencies from the additional info in the package index, resulting in pip being downloaded and installed before the desired package is installed

This is actually less robust, since instead of relying on the setuptools API, you now also rely on the pip API.

If you control requirements.txt, there is nothing "not robust" about parsing it in setup.py.

You should read this: https://caremad.io/posts/2013/07/setup-vs-requirement/, it specifically references this "feature" of pbr.

Why are you using a requirements.txt if you have a setup.py that lists them? `pip install -e` or `setup.py install` should just work in that case.

You don't always want to install the actual package necessarily (e.g. dev) - using requirements separately lets you install the deps but not the package...

What if you have your own package index? You can use `--index-url` in requirements.txt to specify that.

You can use `--index-url` when calling pip: https://pip.pypa.io/en/stable/reference/pip_wheel/#index-url

You can also use `dependency_links` in your setup.py to specify this, which allows deps on github etc.

The approach I've been using

Define my dependencies

- setup.py

- requirements_dev.in

run piptools pip-compile to generate a locked set of dependencies

- requirements.txt

- requirements_dev.txt

It gives me some of the benefit of Rust's Cargo.toml / Cargo.lock in the python world (and actually respects all package's dependency version declarations unlike other tools like pyup).

I'd suggest pipenv for this kind of thing. It will generate a pipfile.lock, which is the (still in development, but pretty stable) official way to create a locked set of deps.