core/pkgs/build-support/fetchgitlab/default.nix

{ lib, fetchgit, fetchzip }:

lib.makeOverridable (
# gitlab example
{ owner, repo, rev, protocol ? "https", domain ? "gitlab.com", group ? null
, pname ? lib.concatStringsSep "-" ([ "source" domain ] ++ (lib.optional (group != null) group) ++ [ owner repo ])
, name ? "${pname}-${rev}"
, fetchSubmodules ? false, leaveDotGit ? false
, deepClone ? false, forceFetchGit ? false
, sparseCheckout ? []
, ... # For hash agility
} @ args:

let
  slug = lib.concatStringsSep "/" ((lib.optional (group != null) group) ++ [ owner repo ]);
  escapedSlug = lib.replaceStrings [ "." "/" ] [ "%2E" "%2F" ] slug;
  escapedRev = lib.replaceStrings [ "+" "%" "/" ] [ "%2B" "%25" "%2F" ] rev;
  passthruAttrs = removeAttrs args [ "protocol" "domain" "owner" "group" "repo" "rev" "fetchSubmodules" "forceFetchGit" "leaveDotGit" "deepClone" ];

  useFetchGit = fetchSubmodules || leaveDotGit || deepClone || forceFetchGit || (sparseCheckout != []);
  fetcher = if useFetchGit then fetchgit else fetchzip;

  gitRepoUrl = "${protocol}://${domain}/${slug}.git";

  fetcherArgs = (if useFetchGit then {
    inherit rev deepClone fetchSubmodules sparseCheckout leaveDotGit;
    url = gitRepoUrl;
  } else {
    url = "${protocol}://${domain}/api/v4/projects/${escapedSlug}/repository/archive.tar.gz?sha=${escapedRev}";

    passthru = {
      inherit gitRepoUrl;
    };
  }) // passthruAttrs // { inherit name; };
in

fetcher fetcherArgs // { meta.homepage = "${protocol}://${domain}/${slug}/"; inherit rev owner repo; }
)