Filtering src recursively when creating a derivation

[lippirk]

I'm creating a derivation using items in a big folder, but I only actually want to use a few files to create the derivation. These files are nested in various directories. So I thought I could use sourceByRegex to select those files. But unfortunately sourceByRegex only seems to search through the top level of a folder.

For example:

$ tree
.
├── 1
├── 2
├── 3
├── default.nix
├── folder
│   ├── 1
│   └── 2
└── result -> /nix/store/951h922h1cx55703yk5fqj1l059d7kvg-my-drv

2 directories, 6 files

$ cat default.nix
{pkgs ? import <nixpkgs> {}}:
pkgs.stdenv.mkDerivation {
  name = "my-drv";
  src = pkgs.lib.sources.sourceByRegex ./. ["2" "folder\/.*"];
  installPhase = ''
    set -e
    mkdir -p $out/bin
    cp -r $src/* $out/bin/
    '';
}

$ ls /nix/store/951h922h1cx55703yk5fqj1l059d7kvg-my-drv/bin
2

I hoped to see the both the file 2 and also folder in that last output, but only 2 was copied.

Is there another way to achieve this?

[infinisil]

Check out #56985, which adds a function to make this pretty easy

[stale]

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