Hash mismatches from generated Nix expressions

[Ma27]

I've seen that there were similar issues in the past (#27, #7), however those were marked as resolved.

I managed to trigger the problem with a fork of js-sequence-diagrams:

[
  { "js-sequence-diagrams": "git+https://github.com/codimd/js-sequence-diagrams.git" }
]

When generating expressions with node2nix -i deps.json and build it with nix-build -E "let i = import ./. {}; in i.\"js-sequence-diagrams-git+https://github.com/codimd/js-sequence-diagrams.git\"", I get the following error:

these derivations will be built:
  /nix/store/mqyqh3lsxb9y8yvdv20bhzhmk98vy0a1-js-sequence-diagrams-b9afa03.drv
  /nix/store/jx3l7j1ac60l9w3lpzcf6nzyawxgr4ky-node-js-sequence-diagrams-2.0.1.drv
building '/nix/store/mqyqh3lsxb9y8yvdv20bhzhmk98vy0a1-js-sequence-diagrams-b9afa03.drv'...
exporting https://github.com/codimd/js-sequence-diagrams.git (rev b9afa038521e5dadf9b97624a3c7db21890be669) into /nix/store/hwpy3klhhyci75cdww0knzanlj8gqx2h-js-sequence-diagrams-b9afa03
Initialized empty Git repository in /nix/store/hwpy3klhhyci75cdww0knzanlj8gqx2h-js-sequence-diagrams-b9afa03/.git/
remote: Enumerating objects: 71, done.
remote: Counting objects: 100% (71/71), done.
remote: Compressing objects: 100% (63/63), done.
remote: Total 71 (delta 16), reused 40 (delta 5), pack-reused 0
From https://github.com/codimd/js-sequence-diagrams
 * branch            HEAD       -> FETCH_HEAD
Switched to a new branch 'fetchgit'
Submodule '_site' (https://github.com/bramp/js-sequence-diagrams.git) registered for path '_site'
Initialized empty Git repository in /nix/store/hwpy3klhhyci75cdww0knzanlj8gqx2h-js-sequence-diagrams-b9afa03/_site/.git/
remote: Enumerating objects: 8, done.
remote: Counting objects: 100% (8/8), done.
remote: Compressing objects: 100% (7/7), done.
remote: Total 1400 (delta 1), reused 8 (delta 1), pack-reused 1392
Receiving objects: 100% (1400/1400), 2.21 MiB | 1.00 MiB/s, done.
Resolving deltas: 100% (821/821), done.
From https://github.com/bramp/js-sequence-diagrams
 * [new branch]      gh-pages   -> origin/gh-pages
 * [new branch]      master     -> origin/master
 * [new branch]      newfont    -> origin/newfont
 * [new branch]      real-tests -> origin/real-tests
 * [new branch]      svg        -> origin/svg
 * [new tag]         v1.0       -> v1.0
 * [new tag]         v1.0.1     -> v1.0.1
 * [new tag]         v1.0.2     -> v1.0.2
 * [new tag]         v1.0.3     -> v1.0.3
 * [new tag]         v1.0.4     -> v1.0.4
 * [new tag]         v1.0.5     -> v1.0.5
 * [new tag]         v1.0.6     -> v1.0.6
 * [new tag]         v2.0.0     -> v2.0.0
 * [new tag]         v2.0.1     -> v2.0.1
Switched to a new branch 'fetchgit'
removing `.git'...
hash mismatch in fixed-output derivation '/nix/store/0h754dqachgmhs9pasv4i4fs0i0iwi3s-js-sequence-diagrams-b9afa03':
  wanted: sha256:1fg3xsyndh7lnd9hqxazv2p01l2p6q5pv72scrcrrf2arbizgk35
  got:    sha256:12v57bdld5a2550xvqh1rcinpld48awgd1s0gbny7z0b0z827ggw
cannot build derivation '/nix/store/jx3l7j1ac60l9w3lpzcf6nzyawxgr4ky-node-js-sequence-diagrams-2.0.1.drv': 1 dependencies couldn't be built
error: build of '/nix/store/jx3l7j1ac60l9w3lpzcf6nzyawxgr4ky-node-js-sequence-diagrams-2.0.1.drv' failed

[svanderburg]

By inspecting the output this seems to be caused by the fact that there is a git sub module, that gets automatically installed by the fetchgit function Nixpkgs. Unfortunately, the function that node2nix uses to compute the hash of a git repository completely ignores sub modules. I think this module needs to be extended with Git sub module support.

[svanderburg]

I just added preliminary git sub module support in revision efa2c2a

I tested the package you provided and it seems to get successfully deployed.

[Ma27]

Great! I'll try to fix the affected package tomorrow and report back :)

[Ma27]

The issue appears to be fixed now, thanks a lot!

(on a side note: I won't change the code in nixpkgs for now as I'd like to get NixOS/nixpkgs#60429 ready as soon as possible).