Technical Notes

Manpages - nix3-flake-check.1

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

#+end_quote

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:

  • apps.=/system/.=/name/
  • =defaultApp.=/system/

The following flake output attributes must be template definitions:

  • 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:

  • =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 --query --available.

Options

  • --all-systems Check the outputs for all systems.
  • --no-build Do not build checks.

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). 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.