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
patchelfflake 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.namedefaultPackage.systemdevShell.systemdevShells.system.namenixosConfigurations.name.config.system.build.toplevelpackages.system.name
The following flake output attributes must be app definitions:
apps.system.namedefaultApp.system
The following flake output attributes must be template definitions:
defaultTemplatetemplates.name
The following flake output attributes must be Nixpkgs overlays:
overlayoverlays.name
The following flake output attributes must be NixOS modules:
nixosModulenixosModules.name
The following flake output attributes must be bundlers:
bundlers.namedefaultBundler
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
-
Check the outputs for all systems.
-
Do not build checks.
Common evaluation options
-
--argname exprPass the value expr as the argument name to Nix functions.
-
--arg-from-filename pathPass the contents of file path as the argument name to Nix functions.
-
--arg-from-stdinnamePass the contents of stdin as the argument name to Nix functions.
-
--argstrname stringPass the string string as the argument name to Nix functions.
-
Start an interactive environment if evaluation fails.
-
--eval-storestore-urlThe URL of the Nix store to use for evaluation, i.e. to store derivations (
.drvfiles) and inputs referenced by them. -
Allow access to mutable paths and repositories.
-
--include/-IpathAdd path to the Nix search path. The Nix search path is initialized from the colon-separated
NIX_PATHenvironment variable, and is used to look up the location of Nix expressions using paths enclosed in angle brackets (i.e.,<nixpkgs>).For instance, passing
-I /home/eelco/Dev -I /etc/nixoswill cause Nix to look for paths relative to
/home/eelco/Devand/etc/nixos, in that order. This is equivalent to setting theNIX_PATHenvironment variable to/home/eelco/Dev:/etc/nixosIt is also possible to match paths against a prefix. For example, passing
-I nixpkgs=/home/eelco/Dev/nixpkgs-branch -I /etc/nixoswill cause Nix to search for
<nixpkgs/path>in/home/eelco/Dev/nixpkgs-branch/pathand/etc/nixos/nixpkgs/path.If a path in the Nix search path starts with
http://orhttps://, it is interpreted as the URL of a tarball that will be downloaded and unpacked to a temporary location. The tarball must consist of a single top-level directory. For example, passing-I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gztells Nix to download and use the current contents of the
masterbranch in thenixpkgsrepository.The URLs of the tarballs from the official
nixos.orgchannels (see the manual page fornix-channel) can be abbreviated aschannel:<channel-name>. For instance, the following two flags are equivalent:-I nixpkgs=channel:nixos-21.05 -I nixpkgs=https://nixos.org/channels/nixos-21.05/nixexprs.tar.xzYou can also fetch source trees using flake URLs and add them to the search path. For instance,
-I nixpkgs=flake:nixpkgsspecifies that the prefix
nixpkgsshall refer to the source tree downloaded from thenixpkgsentry in the flake registry. Similarly,-I nixpkgs=flake:github:NixOS/nixpkgs/nixos-22.05makes
<nixpkgs>refer to a particular branch of theNixOS/nixpkgsrepository on GitHub. -
--override-flakeoriginal-ref resolved-refOverride the flake registries, redirecting original-ref to resolved-ref.
Common flake-related options
-
Commit changes to the flake's lock file.
-
--inputs-fromflake-urlUse the inputs of the specified flake as registry entries.
-
Don't allow lookups in the flake registries.
DEPRECATED
Use
--no-use-registriesinstead. -
Do not allow any updates to the flake's lock file.
-
Do not write the flake's newly generated lock file.
-
--output-lock-fileflake-lock-pathWrite the given lock file instead of
flake.lockwithin the top-level flake. -
--override-inputinput-path flake-urlOverride a specific flake input (e.g.
dwarffs/nixpkgs). This implies--no-write-lock-file. -
Recreate the flake's lock file from scratch.
DEPRECATED
Use
nix flake updateinstead. -
--reference-lock-fileflake-lock-pathRead the given lock file instead of
flake.lockwithin the top-level flake. -
--update-inputinput-pathUpdate a specific flake input (ignoring its previous entry in the lock file).
DEPRECATED
Use
nix flake updateinstead.
Logging-related options
-
Set the logging verbosity level to 'debug'.
-
--log-formatformatSet the format of log output; one of
raw,internal-json,barorbar-with-logs. -
--print-build-logs/-LPrint full build logs on standard error.
-
Decrease the logging verbosity level.
-
--verbose/-vIncrease the logging verbosity level.
Miscellaneous global options
-
Show usage information.
-
Disable substituters and consider all previously downloaded files up-to-date.
-
--optionname valueSet the Nix configuration setting name to value (overriding
nix.conf). -
Consider all previously downloaded files out-of-date.
-
During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.
-
Show version information.
Note
See
man nix.conffor overriding configuration settings with command line flags.