nix3-flake-check(1)

    Warning
    This program is experimental (https://nix.dev/manual/nix/2.34/development/experimental-features.html#xp-feature-nix-command) 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 (./nix3-run.md) :

•   apps.system.default

•   apps.system.name

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

•   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 (./nix3-bundle.md) :

•   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 (#opt-all-systems)

    Check the outputs for all systems.

•   --no-build (#opt-no-build)

    Do not build checks.

  Common evaluation options

•   --arg (#opt-arg) name expr

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

•   --arg-from-file (#opt-arg-from-file) name path

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

•   --arg-from-stdin (#opt-arg-from-stdin) name

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

•   --argstr (#opt-argstr) name string

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

•   --debugger (#opt-debugger)

    Start an interactive environment if evaluation fails.

•   --eval-store (#opt-eval-store) store-url

    The URL of the Nix store (https://nix.dev/manual/nix/2.34/store/types/index.html#store-url-format) to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.

•   --impure (#opt-impure)

    Allow access to mutable paths and repositories.

•   --include (#opt-include) / -I path

    Add path to search path entries used to resolve lookup paths (https://nix.dev/manual/nix/2.34/language/constructs/lookup-path.html)

    This option may be given multiple times.

    Paths added through -I take precedence over the nix-path configuration setting (https://nix.dev/manual/nix/2.34/command-ref/conf-file.html#conf-nix-path) and the NIX_PATH environment variable (https://nix.dev/manual/nix/2.34/command-ref/env-common.html#env-NIX_PATH) .

•   --override-flake (#opt-override-flake) original-ref resolved-ref

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

  Common flake-related options

•   --commit-lock-file (#opt-commit-lock-file)

    Commit changes to the flake’s lock file.

•   --inputs-from (#opt-inputs-from) flake-url

    Use the inputs of the specified flake as registry entries.

•   --no-registries (#opt-no-registries)

    Don’t allow lookups in the flake registries.

        DEPRECATED

        Use --no-use-registries (https://nix.dev/manual/nix/2.34/command-ref/conf-file.html#conf-use-registries) instead.

•   --no-update-lock-file (#opt-no-update-lock-file)

    Do not allow any updates to the flake’s lock file.

•   --no-write-lock-file (#opt-no-write-lock-file)

    Do not write the flake’s newly generated lock file.

•   --output-lock-file (#opt-output-lock-file) flake-lock-path

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

•   --override-input (#opt-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 (#opt-recreate-lock-file)

    Recreate the flake’s lock file from scratch.

        DEPRECATED

        Use nix flake update (https://nix.dev/manual/nix/2.34/command-ref/new-cli/nix3-flake-update.html) instead.

•   --reference-lock-file (#opt-reference-lock-file) flake-lock-path

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

•   --update-input (#opt-update-input) input-path

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

        DEPRECATED

        Use nix flake update (https://nix.dev/manual/nix/2.34/command-ref/new-cli/nix3-flake-update.html) instead.

  Logging-related options

•   --debug (#opt-debug)

    Set the logging verbosity level to ‘debug’.

•   --log-format (#opt-log-format) format

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

•   --print-build-logs (#opt-print-build-logs) / -L

    Print full build logs on standard error.

•   --quiet (#opt-quiet)

    Decrease the logging verbosity level.

•   --verbose (#opt-verbose) / -v

    Increase the logging verbosity level.

  Miscellaneous global options

•   --help (#opt-help)

    Show usage information.

•   --offline (#opt-offline)

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

•   --option (#opt-option) name value

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

•   --refresh (#opt-refresh)

    Consider all previously downloaded files out-of-date.

•   --repair (#opt-repair)

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

•   --version (#opt-version)

    Show version information.

    Note

    See man nix.conf (https://nix.dev/manual/nix/2.34/command-ref/conf-file.html#command-line-flags) for overriding configuration settings with command line flags.