Request for nix-build to have a flag that disables the checkPhase.

[CMCDragonkai]

This is a feature request. I would find it quite useful to have a flag with nix-build to skip the checkPhase. I know this is possible by overriding the derivation, wouldn't having a flag for this be way more convenient so that it can be done on the command line instead.

The main reason for this is that in some cases tests cannot be run on the machine where the build is occurring. For example I have an application that has a checkPhase running tests that involve the GPU. But on machines without the GPU they can still build the output, but cannot run the tests.

[matthewbauer]

This will probably require changing how Nix works. Right now if you set doCheck = false everywhere, Nix will try to rebuild all of your packages with doCheck = true and you can't use the binary cache. We need a way to tell Nix that some attrs are "impure" and to not put them in the .drv file.

[FRidh]

Probably best then to move the tests into a separate derivation and use requiredSystemFeatures in that one.

Anyway, this is a Nix issue, not Nixpkgs, so closing.

[CMCDragonkai]

What do you mean requiredSystemFeatures?

[FRidh]

@CMCDragonkai please check the Nix manual...

[danbst]

btw, there is also config.doCheckByDefault

[CMCDragonkai]

@FRidh So I see that requiredSystemFeatures can be used in conjunction with system-features of the nix.conf. This basically allows us to state that a derivation can only run on a system with given set of features. Are these features just arbitrary strings? Is there a way to say nvidia and for something to actually check if an NVIDIA GPU exists? Or is that something I need to code into the configuration.nix by checking for the existence of /dev/nvidiactl?

[FRidh]

These are indeed just strings. No, there is no way to check for this, it's all declarative.

[raboof]

(sorry to revive such an old issue, but it seems it's still well-indexed by search engines)

I have an application that has a checkPhase running tests that involve the GPU. But on machines without the GPU they can still build the output, but cannot run the tests.

Where possible it's preferable to move those from checkPhase (or installCheckPhase) to passthru.tests - more details in https://nixos.org/manual/nixpkgs/unstable/#var-meta-tests

[hraban]

Anyway, this is a Nix issue, not Nixpkgs, so closing.

I thought the very concept of the checkPhase, or just phases in general, was not just nixpkgs but stdenv specific. How is it a nix issue?

A work-around for anyone who needs to rebuild an entire system from stdenv as fast as possible without checks:

nix build --impure --expr '
let
  disableCheckIfDeriv = deriv: (deriv.overrideAttrs or (_: deriv)) {doCheck = false; doInstallCheck = false;};
  p = import /your/nixpkgs {
    config = {replaceStdenv = {pkgs}: pkgs.fastStdenv; };
    overlays = [(self: builtins.mapAttrs (name: disableCheckIfDeriv))];
  };
in
  p.hello
'