Feature: --pre installs for pre-release and development versions

[tlambert03]

Just starting with hatch. Love it, thank you so much!

Apologies if I've missed this feature somewhere: I'm looking for a flag that would allow me to install pre-release and development versions in a hatch environment (i.e. with pip install --pre; akin to pip_pre in tox). I looked through the docs, source code, and issues and didn't find anything yet.

(The motivation is that, as a part of CI, I'd like to run my tests with pre-releases)

thanks!!

[blink1073]

I second this request; ideally we could pass arbitrary arguments to pip, since we also have a job that uses a constraints file to install the minimum versions of dependencies.

[ofek]

Hey thanks!

You can use env vars https://hatch.pypa.io/1.6/how-to/environment/package-indices/

[tlambert03]

Thanks @ofek! I'm afraid I might need slightly more detail than that.
I looked through the pip docs on pre-release versions and environment variables, and did some googling, but still can't find an env var (or a package index url) that pip would use to toggle installing pre-releases. do you happen to know it off the top of your head?

[blink1073]

export PIP_PRE=1 worked for me locally.

[blink1073]

So in my other use case it would be export PIP_CONSTRAINT=<file_path>.

[ofek]

https://pip.pypa.io/en/stable/topics/configuration/#environment-variables

[tool.hatch.envs.default.env-vars]
PIP_PRE = "1"

[tlambert03]

Thanks both. Much appreciated

[flying-sheep]

Figured out how do do it from the advanced env docs and uv’s env var docs:

[[envs.hatch-test.matrix]]
python = ["3.12"]
deps = ["stable", "pre"]
[envs.hatch-test.overrides]
matrix.deps.env-vars = [
  { key = "UV_PRERELEASE", value = "allow", if = ["pre"] },
]