Inject runtime dependency into nix package

Question

Adding a runtime dependency to a package through override buildInputs causes the package to rebuild. Is there a simple way to inject runtime dependencies into a package without recompiling?

So basically adding package/bin to PATH and package/lib to LD_LIBRARY_PATH

That would defeat the whole purpose of being purely functional, wouldn't it? (-> NO) — Daniel Jour, Jun 16 '16 at 21:55
actually I think there is a way, looking at cc-wrapper, it swaps out binutils for example without having to rebuild gcc, so you could also use it to add a runtime dependency. `echo ${toString extraPackages} > $out/nix-support/propagated-native-build-inputs` — dvc, Jun 16 '16 at 22:19
So you mean to change the environment used when a Nix-installed app is *run*, not the one used when it is *built*, right? — akavel, Jul 21 '16 at 18:27

score 2 · Accepted Answer · answered Jul 21 '16 at 18:48

If I understand correctly that you want to tweak the environment used when a Nix-installed app is run, not the one used when it is built, then a method I know of is as follows below. By using it, you essentially create a wrapper script, which overrides the "default command". So, something similar like creating e.g. a custom ~/bin/vim script, which adds some options/env overrides to the default vim binary, which is called with a "hardcoded original path" inside the script.

One example of it in nixpkgs is how vimutils.vimWithRC overrides vim command with a custom script. For your own use, you could write more or less something like below:

with import <nixpkgs> {};

writeScriptBin "vim" ''
  #!/usr/bin/env bash
  export PATH=package/bin:$PATH   # whatever you like; I've added what you asked for
  export LD_LIBRARY_PATH=package/lib:$LD_LIBRARY_PATH
  ${vim}/bin/vim --my-options "$@"
'';

If you put it in my-vim.nix, you should be able to install it with:

$ nix-env -e vim   # REMOVE NORMAL VIM. I think this should be done first to avoid conflict
$ nix-env -i -f my-vim.nix

And hopefully it'll work and "override" the default vim for you.

DISCLAIMER: I haven't actually tested it in this exact form, sorry. Don't have a Nix console handy at this moment, unfortunately.

Inject runtime dependency into nix package

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