Python dependencies are no longer checked

[bbjubjub2494]

Describe the bug

The python tooling does not enforce the presence of dependencies at build time when doCheck is set to false.

Steps To Reproduce

Steps to reproduce the behavior:

1. nix build github/lourkeur/nixpkgs-python-dependency-bypass

Expected behavior

The build should fail with ERROR; Could not find a version that satisfies the requirement [...]

Screenshots

If applicable, add screenshots to help explain your problem.

Additional context

Introduced in #248866

Notify maintainers

@tjni and @FRidh for the bisected commits (6c85fff,0d7647889c6701d8a0e6fa784e886012011ca2d8)

Metadata

Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

[user@system:~]$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 6.1.47, NixOS, 23.05 (Stoat), 23.05pre-git`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.13.5`
 - nixpkgs: `/etc/nix/channels/nixos`

[yajo]

Could this be a good thing? Since long ago it's been a problem that you need runtime dependencies when building a python package in nixpkgs. You should only need buildtime dependencies, and runtime ones for installing it (not building it). See the whole story in #170577 and #26400.

[bbjubjub2494]

I encountered this in a context where it is bad because I have a package with doCheck = false (chia) and as a result I am able to successfully build with clearly outdated dependencies. I also don't think it is intended behavior but this could be discussed.

[erikarvstedt]

Dependencies are no longer checked at all, regardless of the value of doCheck. See #253872 for a repro.
(@lourkeur, can you update your description?)

More concretely, it is neither checked whether a requirement exists at all nor whether the required version matches.

I've confirmed this for format = "setuptools" (the default) and format = "pyproject".

This is a major regression.
@FRidh, was this a deliberate design choice?

Workaround

Add the following to your buildPythonPackage drv:

# Enable Python requirements check
dontUsePypaInstall = true;
nativeBuildInputs = [ pipInstallHook ];

[bbjubjub2494]

With my poc (same as OP but updated) it's different:

doCheck | setuptools | pyproject
false        | bad           | bad
true         | good         | bad

bad: no dependency check, successful build
good: dependency check and error

I can also show that in the pyproject case, if I add pythonImportsCheckHook, it fixes it. It's usually a good idea to add it anyways but I discovered that randomly earlier today.

[natsukium]

The dependency check has now been introduced in python-updates branch as pythonRuntimeDepsCheckHook.