yadm: install from build directory instead of $src

[abathur]

Motivation for this change

Noticed while trying to use substituteInPlace from prePatch that my changes
weren't applying to the installed copy.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

You can see this by adding something silly like:

prePatch = ''
  substituteInPlace yadm --replace "Tim Byrne" "Bim Tyrne"
'';
postInstall = "diff -u yadm $out/bin/yadm | head";

Which, in the build output, looks like:

building
Overwrote '/private/var/folders/8g/qgvf93_s1_b40dd8nhsvqk_m0000gn/T/nix-build-yadm-2.4.0.drv-0/source/yadm'
installing
--- yadm        2020-04-02 00:05:55.973420427 +0000
+++ /nix/store/czxzg7xd8hsnk4r1za7biiyvkb5wh28s-yadm-2.4.0/bin/yadm     2020-04-02 00:05:55.990144968 +0000
@@ -1,6 +1,6 @@
 #!/bin/sh
 # yadm - Yet Another Dotfiles Manager
-# Copyright (C) 2015-2020 Bim Tyrne
+# Copyright (C) 2015-2020 Tim Byrne
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by

[stale]

Hello, I'm a bot and I thank you in the name of the community for your contributions.

Nixpkgs is a busy repository, and unfortunately sometimes PRs get left behind for too long. Nevertheless, we'd like to help committers reach the PRs that are still important. This PR has had no activity for 180 days, and so I marked it as stale, but you can rest assured it will never be closed by a non-human.

If this is still important to you and you'd like to remove the stale label, we ask that you leave a comment. Your comment can be as simple as "still important to me". But there's a bit more you can do:

If you received an approval by an unprivileged maintainer and you are just waiting for a merge, you can @ mention someone with merge permissions and ask them to help. You might be able to find someone relevant by using Git blame on the relevant files, or via GitHub's web interface. You can see if someone's a member of the nixpkgs-committers team, by hovering with the mouse over their username on the web interface, or by searching them directly on the list.

If your PR wasn't reviewed at all, it might help to find someone who's perhaps a user of the package or module you are changing, or alternatively, ask once more for a review by the maintainer of the package/module this is about. If you don't know any, you can use Git blame on the relevant files, or GitHub's web interface to find someone who touched the relevant files in the past.

If your PR has had reviews and nevertheless got stale, make sure you've responded to all of the reviewer's requests / questions. Usually when PR authors show responsibility and dedication, reviewers (privileged or not) show dedication as well. If you've pushed a change, it's possible the reviewer wasn't notified about your push via email, so you can always officially request them for a review, or just @ mention them and say you've addressed their comments.

Lastly, you can always ask for help at our Discourse Forum, or more specifically, at this thread or at #nixos' IRC channel.

[abathur]

Still important

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/prs-ready-for-review/3032/408