Install dependencies from pyproject.toml like from requirements.txt with -r, (again) #13449
Description
What's the problem this feature will solve?
If you don't want to install a package but you do want to install dependencies, we don't have options outside of adding a second dependencies list (a requirements.txt), when all the dependencies are already listed in pyproject.toml. This means people working on a library need to duplicate dependency lists (common) or create on-demand requirements.txt files that aren't checked in (also common), when we really just need a pip install -r ./pyproject.toml that works like pip install ./requirements.txt.
Currently, repos are shipping with pyproject.toml files instead of requirements.txt files. The problem is that without a requirements.txt, there's no way to just install the requirements for these libraries as you work on them. We are seeing that several repos have brutish systems trying to both-ways it, or to simply force developers to write their own requirements.txt files if they want to develop the library. Examples:
- https://github.com/psf/black
- no requirements.txt file
- https://github.com/pydantic/pydantic
- no requirements.txt file
- https://github.com/pytest-dev/pytest
- no requirements.txt file
- https://github.com/pypa/pip (lol)
- no requirements.txt file
And then you have other repos that bend over backwards to support pip and pyproject.toml. FastAPI has one pyproject.toml file, and 7 requirements.txt files in its root directory. Yikes!
Describe the solution you'd like
Expected interface:
pip install -r ./pyproject.toml
pip install -r ./pyproject.toml[dev]
Result:
install the dependencies defined in pyproject.toml
install the dependencies defined in pyproject.toml, plus dev dependencies
The advantage here is that we don't need a separate requirements.txt file, or several, and we can as a community standardize on one place to have dependencies listed.
Alternative Solutions
--deps-only doesn't seem to work in this case
The original recommendation, adding an additional dep in pip tools, is not what we want either. The whole point is a working tool chain with batteries included:
$ pip install pip-tools
$ python -m piptools compile \
-o requirements.txt \
pyproject.toml
$ pip install -r requirements.txt
Don't forget the chatgpt oneliners:
python -c "import tomllib; deps = tomllib.load(open('pyproject.toml', 'rb'))['project']['dependencies']; open('requirements.txt', 'w').write('\n'.join(deps))"
Additional context
pyproject.toml is gaining traction as as both a sane and popular way to define a python library, a rare gem in any large community. However, with its popularity we're seeing standardization, and the new standard is to include pyproject.toml and to skip requirements.txt.
The issue I found on this subject, Support installing requirements from arbitrary keys in pyproject.toml #8049, is not what we're talking about, as pip install -r pyproject.toml --key tool.enscons.install_requires was already rejected, and anyway the interface is not the greatest.
#11584 was opened, but closed in favor of #8049. #8049 was closed for reasons described in the thread.
We still have plenty of python repos with only a pyproject.toml file, and we need to either generate our own requirements.txt files or we need
Code of Conduct
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