nix3-why-depends(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 why-depends - show why a package has another package in its closure

Synopsis

nix why-depends [option…] package dependency

Examples

•   Show one path through the dependency graph leading from Hello to Glibc:

    # nix why-depends nixpkgs#hello nixpkgs#glibc
    /nix/store/10l19qifk7hjjq47px8m2prqk1gv4isy-hello-2.10
    └───bin/hello: …...................../nix/store/kmmr0ggkywxvnad4z1chqb6lsxi6pqgc-glibc-2.32/lib/ld-linux-x86-64.…
      → /nix/store/kmmr0ggkywxvnad4z1chqb6lsxi6pqgc-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/0my2p7psgdzqc5pq6dyl4ld9w6g0np58-thunderbird-78.5.1
    ├───lib/thunderbird/libxul.so: …6wrw-libxcb-1.14/lib:/nix/store/jmwiq1bb3n47a0css8b1q7lhgf7416k5-libX11-1.7.0/lib:/nix/store/ssf…
    │   → /nix/store/jmwiq1bb3n47a0css8b1q7lhgf7416k5-libX11-1.7.0
    ├───lib/thunderbird/libxul.so: …pxyc-libXt-1.2.0/lib:/nix/store/l1sv43bafhkf2iikmdw9y62aybjdhcmm-libXdamage-1.1.5/lib:/nix/store…
    │   → /nix/store/l1sv43bafhkf2iikmdw9y62aybjdhcmm-libXdamage-1.1.5
    │   ├───lib/libXdamage.so.1.1.0: …-libXfixes-5.0.3/lib:/nix/store/jmwiq1bb3n47a0css8b1q7lhgf7416k5-libX11-1.7.0/lib:/nix/store/9l0…
    │   │   → /nix/store/jmwiq1bb3n47a0css8b1q7lhgf7416k5-libX11-1.7.0
    …

•   Show why Glibc depends on itself:

    # nix why-depends nixpkgs#glibc nixpkgs#glibc
    /nix/store/q9mknq836i0kblq8g1hm9f3cv9qda0r9-glibc-2.31
    └───lib/ld-2.31.so: …che       Do not use /nix/store/q9mknq836i0kblq8g1hm9f3cv9qda0r9-glibc-2.31/etc/ld.so.cache.  --…
      → /nix/store/q9mknq836i0kblq8g1hm9f3cv9qda0r9-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

Nix 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/q9mknq836i0kblq8g1hm9f3cv9qda0r9-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. Nix 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 Nix 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 (#opt-all) / -a

    Show all edges in the dependency graph leading from package to dependency, rather than just a shortest path.

•   --precise (#opt-precise)

    For each edge in the dependency graph, show the files in the parent that cause the dependency.

  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.

  Options that change the interpretation of installables

•   --derivation (#opt-derivation)

    Operate on the store derivation (https://nix.dev/manual/nix/2.34/glossary.html#gloss-store-derivation) rather than its outputs.

•   --expr (#opt-expr) expr

    Interpret installables (https://nix.dev/manual/nix/2.34/command-ref/new-cli/nix.html#installables) as attribute paths relative to the Nix expression expr.

•   --file (#opt-file) / -f file

    Interpret installables (https://nix.dev/manual/nix/2.34/command-ref/new-cli/nix.html#installables) as attribute paths relative to the Nix expression stored in file. If file is the character -, then a Nix expression is read from standard input. Implies --impure.

    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.