gh: option to enable helper for additional hosts (#4288)

* gh: option to enable helper for additional hosts

`gh` can also be used with github enterprise
hosts, for which there exists no easy option
to enable the credential helper except for
directly working with `programs.git.extraConfig`.
Not sure if this is a needed addition since it's
somewhat niche, at the same time it's not very
complex and makes the life of github enterprise
a little easier.

* gh: update credential-helper tests

* gh: refactor credential helper option

this moves from `enableGitCredentialHelper` to
`gitCredentialHelper.enable` and
`gitCredentialHelper.hosts`.

* gh: lib.mkIf -> mkIf

modules/programs/gh.nix

@@ -60,6 +60,12 @@ in {
         "settings"
         "git_protocol"
       ])
+      (mkRenamedOptionModule [ "programs" "gh" "enableGitCredentialHelper" ] [
+        "programs"
+        "gh"
+        "gitCredentialHelper"
+        "enable"
+      ])
     ];
 
   options.programs.gh = {
@@ -91,11 +97,21 @@ in {
       '';
     };
 
-    enableGitCredentialHelper =
-      mkEnableOption "the gh git credential helper for github.com" // {
+    gitCredentialHelper = {
+      enable = mkEnableOption "the gh git credential helper" // {
         default = true;
       };
 
+      hosts = mkOption {
+        type = types.listOf types.str;
+        default = [ "https://github.com" ];
+        description = "GitHub hosts to enable the gh git credential helper for";
+        example = literalExpression ''
+          [ "https://github.com" "https://github.example.com" ]
+        '';
+      };
+    };
+
     extensions = mkOption {
       type = types.listOf types.package;
       default = [ ];
@@ -112,9 +128,11 @@ in {
     xdg.configFile."gh/config.yml".source =
       yamlFormat.generate "gh-config.yml" cfg.settings;
 
-    programs.git.extraConfig.credential."https://github.com".helper =
-      mkIf cfg.enableGitCredentialHelper
-      "${cfg.package}/bin/gh auth git-credential";
+    programs.git.extraConfig.credential = mkIf cfg.gitCredentialHelper.enable
+      (builtins.listToAttrs (map (host:
+        lib.nameValuePair host {
+          helper = "${cfg.package}/bin/gh auth git-credential";
+        }) cfg.gitCredentialHelper.hosts));
 
     xdg.dataFile."gh/extensions" = mkIf (cfg.extensions != [ ]) {
       source = pkgs.linkFarm "gh-extensions" (builtins.map (p: {

tests/modules/programs/gh/credential-helper.git.conf

@@ -1,2 +1,5 @@
 [credential "https://github.com"]
 	helper = "@gh@/bin/gh auth git-credential"
+
+[credential "https://github.example.com"]
+	helper = "@gh@/bin/gh auth git-credential"

tests/modules/programs/gh/credential-helper.nix

@@ -3,7 +3,10 @@
 {
   programs.gh = {
     enable = true;
-    enableGitCredentialHelper = true;
+    gitCredentialHelper = {
+      enable = true;
+      hosts = [ "https://github.com" "https://github.example.com" ];
+    };
   };
 
   programs.git.enable = true;