Warning
This program is experimental and its interface is subject to change.
Name
nix why-depends - show why a package has another package in its closure
Synopsis
nix why-depends [option...] package dependency
Note: this command's interface is based heavily around installables, which you may want to read about first (nix --help).
Examples
-
Show one path through the dependency graph leading from Hello to Glibc:
# nix why-depends nixpkgs#hello nixpkgs#glibc /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10 └───bin/hello: …...................../nix/store/9l06v7fc38c1x3r2iydl15ksgz0ysb82-glibc-2.32/lib/ld-linux-x86-64.… → /nix/store/9l06v7fc38c1x3r2iydl15ksgz0ysb82-glibc-2.32 -
Show all files and paths in the dependency graph leading from Thunderbird to libX11:
# nix why-depends --all nixpkgs#thunderbird nixpkgs#xorg.libX11 /nix/store/qfc8729nzpdln1h0hvi1ziclsl3m84sr-thunderbird-78.5.1 ├───lib/thunderbird/libxul.so: …6wrw-libxcb-1.14/lib:/nix/store/adzfjjh8w25vdr0xdx9x16ah4f5rqrw5-libX11-1.7.0/lib:/nix/store/ssf… │ → /nix/store/adzfjjh8w25vdr0xdx9x16ah4f5rqrw5-libX11-1.7.0 ├───lib/thunderbird/libxul.so: …pxyc-libXt-1.2.0/lib:/nix/store/1qj29ipxl2fyi2b13l39hdircq17gnk0-libXdamage-1.1.5/lib:/nix/store… │ → /nix/store/1qj29ipxl2fyi2b13l39hdircq17gnk0-libXdamage-1.1.5 │ ├───lib/libXdamage.so.1.1.0: …-libXfixes-5.0.3/lib:/nix/store/adzfjjh8w25vdr0xdx9x16ah4f5rqrw5-libX11-1.7.0/lib:/nix/store/9l0… │ │ → /nix/store/adzfjjh8w25vdr0xdx9x16ah4f5rqrw5-libX11-1.7.0 … -
Show why Glibc depends on itself:
# nix why-depends nixpkgs#glibc nixpkgs#glibc /nix/store/9df65igwjmf2wbw0gbrrgair6piqjgmi-glibc-2.31 └───lib/ld-2.31.so: …che Do not use /nix/store/9df65igwjmf2wbw0gbrrgair6piqjgmi-glibc-2.31/etc/ld.so.cache. --… → /nix/store/9df65igwjmf2wbw0gbrrgair6piqjgmi-glibc-2.31 -
Show why Geeqie has a build-time dependency on
systemd:# nix why-depends --derivation nixpkgs#geeqie nixpkgs#systemd /nix/store/drrpq2fqlrbj98bmazrnww7hm1in3wgj-geeqie-1.4.drv └───/: …atch.drv",["out"]),("/nix/store/qzh8dyq3lfbk3i1acbp7x9wh3il2imiv-gtk+3-3.24.21.drv",["dev"]),("/… → /nix/store/qzh8dyq3lfbk3i1acbp7x9wh3il2imiv-gtk+3-3.24.21.drv └───/: …16.0.drv",["dev"]),("/nix/store/8kp79fyslf3z4m3dpvlh6w46iaadz5c2-cups-2.3.3.drv",["dev"]),("/nix… → /nix/store/8kp79fyslf3z4m3dpvlh6w46iaadz5c2-cups-2.3.3.drv └───/: ….3.1.drv",["out"]),("/nix/store/yd3ihapyi5wbz1kjacq9dbkaq5v5hqjg-systemd-246.4.drv",["dev"]),("/… → /nix/store/yd3ihapyi5wbz1kjacq9dbkaq5v5hqjg-systemd-246.4.drv
Description
Lix automatically determines potential runtime dependencies between
store paths by scanning for the hash parts of store paths. For
instance, if there exists a store path
/nix/store/9df65igwjmf2wbw0gbrrgair6piqjgmi-glibc-2.31, and a file
inside another store path contains the string 9df65igw…, then the
latter store path refers to the former, and thus might need it at
runtime. Lix always maintains the existence of the transitive closure
of a store path under the references relationship; it is therefore not
possible to install a store path without having all of its references
present.
Sometimes Lix packages end up with unexpected runtime dependencies; for instance, a reference to a compiler might accidentally end up in a binary, causing the former to be in the latter's closure. This kind of closure size bloat is undesirable.
nix why-depends allows you to diagnose the cause of such issues. It
shows why the store path package depends on the store path
dependency, by showing a shortest sequence in the references graph
from the former to the latter. Also, for each node along this path, it
shows a file fragment containing a reference to the next store path in
the sequence.
To show why derivation package has a build-time rather than runtime
dependency on derivation dependency, use --derivation.
Options
-
--all/-aShow all edges in the dependency graph leading from package to dependency, rather than just a shortest path. -
--preciseFor each edge in the dependency graph, show the files in the parent that cause the dependency.
Common evaluation options:
-
--argname expr Pass the value expr as the argument name to Nix functions. -
--argstrname string Pass the string string as the argument name to Nix functions. -
--debuggerStart an interactive environment if evaluation fails. -
--eval-storestore-url The URL of the Nix store to use for evaluation, i.e. to store derivations (.drvfiles) and inputs referenced by them. -
--impureAllow access to mutable paths and repositories. -
--include/-Ipath Add path to the Nix search path. The Nix search path is initialized from the colon-separatedNIX_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 Lix 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 Lix 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 Lix 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-ref Override the flake registries, redirecting original-ref to resolved-ref.
Common flake-related options:
-
--commit-lock-fileCommit changes to the flake's lock file. -
--inputs-fromflake-url Use the inputs of the specified flake as registry entries. -
--no-registriesDon't allow lookups in the flake registries. This option is deprecated; use--no-use-registries. -
--no-update-lock-fileDo not allow any updates to the flake's lock file. -
--no-write-lock-fileDo not write the flake's newly generated lock file. -
--output-lock-fileflake-lock-path Write the given lock file instead offlake.lockwithin the top-level flake. -
--override-inputinput-path flake-url Override a specific flake input (e.g.dwarffs/nixpkgs). This implies--no-write-lock-file. -
--reference-lock-fileflake-lock-path Read the given lock file instead offlake.lockwithin the top-level flake.
Logging-related options:
-
--debugSet the logging verbosity level to 'debug'. -
--log-formatformat Set the format of log output; one ofraw,internal-json,bar,bar-with-logs,multilineormultiline-with-logs. -
--print-build-logs/-LPrint full build logs on standard error. -
--quietDecrease the logging verbosity level. -
--verbose/-vIncrease the logging verbosity level.
Miscellaneous global options:
-
--helpShow usage information. -
--offlineDisable substituters and consider all previously downloaded files up-to-date. -
--optionname value Set the Lix configuration setting name to value (overridingnix.conf). -
--refreshConsider all previously downloaded files out-of-date. -
--repairDuring evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths. -
--versionShow version information.
Options that change the interpretation of installables:
-
--derivationOperate on the store derivation rather than its outputs. -
--expr/-Eexpr Interpret installables as attribute paths relative to the Nix expression expr. -
--file/-ffile Interpret installables as attribute paths relative to the Nix expression stored in file. If file is the character -, then a Nix expression will be read from standard input. Implies--impure.
Note
See
man nix.conffor overriding configuration settings with command line flags.