nix3-flake-check(1)

Warning: This program is experimental and its interface is subject to change.

Name
nix flake check - check whether the flake evaluates and run its tests

Synopsis
nix flake check [option…] flake-url

Examples

•   Evaluate the flake in the current directory, and build its checks:

    # nix flake check

•   Verify that the patchelf flake evaluates, but don’t build its checks:

    # nix flake check --no-build github:NixOS/patchelf

Description
This command verifies that the flake specified by flake reference flake-url can be evaluated successfully (as detailed below), and that the derivations specified by the flake’s checks output can be built successfully.

If the keep-going option is set to true, Nix will keep evaluating as much as it can and report the errors as it encounters them. Otherwise it will stop at the first error.

Evaluation checks
The following flake output attributes must be derivations:

•   checks.system.name

•   defaultPackage.system

•   devShell.system

•   devShells.system.name

•   nixosConfigurations.name.config.system.build.toplevel

•   packages.system.name

The following flake output attributes must be app definitions (./nix3-run.md):

•   apps.system.name

•   defaultApp.system

The following flake output attributes must be template definitions (./nix3-flake-init.md):

•   defaultTemplate

•   templates.name

The following flake output attributes must be Nixpkgs overlays:

•   overlay

•   overlays.name

The following flake output attributes must be NixOS modules:

•   nixosModule

•   nixosModules.name

The following flake output attributes must be bundlers (./nix3-bundle.md):

•   bundlers.name

•   defaultBundler

In addition, the hydraJobs output is evaluated in the same way as Hydra’s hydra-eval-jobs (i.e. as a arbitrarily deeply nested attribute set of derivations). Similarly, the legacyPackages.system output is evaluated like nix-env -qa.

Options

•   --no-build
    Do not build checks.

Common evaluation options:

•   --arg name expr
    Pass the value expr as the argument name to Nix functions.

•   --argstr name string
    Pass the string string as the argument name to Nix functions.

•   --eval-store store-url
    The Nix store to use for evaluations.

•   --impure
    Allow access to mutable paths and repositories.

•   --include / -I path
    Add path to the list of locations used to look up <...> file names.

•   --override-flake original-ref resolved-ref
    Override the flake registries, redirecting original-ref to resolved-ref.

Common flake-related options:

•   --commit-lock-file
    Commit changes to the flake’s lock file.

•   --inputs-from flake-url
    Use the inputs of the specified flake as registry entries.

•   --no-registries
    Don’t allow lookups in the flake registries. This option is deprecated; use --no-use-registries.

•   --no-update-lock-file
    Do not allow any updates to the flake’s lock file.

•   --no-write-lock-file
    Do not write the flake’s newly generated lock file.

•   --override-input input-path flake-url
    Override a specific flake input (e.g. dwarffs/nixpkgs). This implies --no-write-lock-file.

•   --recreate-lock-file
    Recreate the flake’s lock file from scratch.

•   --update-input input-path
    Update a specific flake input (ignoring its previous entry in the lock file).