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

•   devShells.system.default

•   devShells.system.name

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

•   packages.system.default

•   packages.system.name

The following flake output attributes must be app definitions:

•   apps.system.default

•   apps.system.name

The following flake output attributes must be template definitions:

•   templates.default

•   templates.name

The following flake output attributes must be Nixpkgs overlays:

•   overlays.default

•   overlays.name

The following flake output attributes must be NixOS modules:

•   nixosModules.default

•   nixosModules.name

The following flake output attributes must be bundlers:

•   bundlers.default

•   bundlers.name

Old default attributes are renamed, they will work but will emit a warning:

•   defaultPackage.<system> → packages.system.default

•   defaultApps.<system> → apps.system.default

•   defaultTemplate → templates.default

•   defaultBundler.<system> → bundlers.system.default

•   overlay → overlays.default

•   devShell.<system> → devShells.system.default

•   nixosModule → nixosModules.default

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 --query --available.

Options

•   --all-systems

    Check the outputs for all systems.

•   --no-build

    Do not build checks.

•   --out-link / -o path

    Use path as prefix for the symlinks to the check results. By default, no out links are created.

•   --print-out-paths

    Print the resulting output paths

  Common evaluation options

•   --arg name expr

    Pass the value expr as the argument name to Nix functions.

•   --arg-from-file name path

    Pass the contents of file path as the argument name to Nix functions.

•   --arg-from-stdin name

    Pass the contents of stdin as the argument name to Nix functions.

•   --argstr name string

    Pass the string string as the argument name to Nix functions.

•   --debugger

    Start an interactive environment if evaluation fails.

•   --eval-store store-url

    The URL of the Nix store to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.

•   --impure

    Allow access to mutable paths and repositories.

•   --include / -I path

    Add path to search path entries used to resolve lookup paths

    This option may be given multiple times.

    Paths added through -I take precedence over the nix-path configuration setting and the NIX_PATH environment variable.

•   --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.

        DEPRECATED

        Use --no-use-registries instead.

•   --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.

•   --output-lock-file flake-lock-path

    Write the given lock file instead of flake.lock within the top-level flake.

•   --override-input input-path flake-url

    Override a specific flake input (e.g. dwarffs/nixpkgs). The input path must not be empty. This implies --no-write-lock-file.

•   --recreate-lock-file

    Recreate the flake’s lock file from scratch.

        DEPRECATED

        Use nix flake update instead.

•   --reference-lock-file flake-lock-path

    Read the given lock file instead of flake.lock within the top-level flake.

•   --update-input input-path

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

        DEPRECATED

        Use nix flake update instead.

  Logging-related options

•   --debug

    Set the logging verbosity level to ‘debug’.

•   --log-format format

    Set the format of log output; one of raw, internal-json, bar or bar-with-logs.

•   --print-build-logs / -L

    Print full build logs on standard error.

•   --quiet

    Decrease the logging verbosity level.

•   --verbose / -v

    Increase the logging verbosity level.

  Miscellaneous global options

•   --help

    Show usage information.

•   --offline

    Disable substituters and consider all previously downloaded files up-to-date.

•   --option name value

    Set the Nix configuration setting name to value (overriding nix.conf).

•   --refresh

    Consider all previously downloaded files out-of-date.

•   --repair

    During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.

•   --version

    Show version information.

    Note

    See man nix.conf for overriding configuration settings with command line flags.