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).

                                                                                             nix3-flake-check(1)