darcs: add defaults

This adds support for specifying default values for Darcs commands.

modules/programs/darcs.nix

@@ -37,6 +37,19 @@ in
         ];
         description = "File patterns to ignore";
       };
+
+      defaults = lib.mkOption {
+        type = lib.types.nullOr lib.types.lines;
+        default = "";
+        example = ''
+          ALL ignore-times
+        '';
+        description = ''
+          Default values for Darcs commands.
+
+          See <https://darcs.net/Using/Configuration#defaults> for details.
+        '';
+      };
     };
   };
 
@@ -52,6 +65,9 @@ in
         home.file.".darcs/boring".text = lib.concatMapStrings (x: x + "\n") cfg.boring;
       })
 
+      (lib.mkIf (cfg.defaults != null) {
+        home.file.".darcs/defaults".text = cfg.defaults;
+      })
     ]
   );
 }

tests/modules/programs/darcs/default.nix

@@ -1,4 +1,5 @@
 {
   darcs-author = ./author.nix;
   darcs-boring = ./boring.nix;
+  darcs-defaults = ./defaults.nix;
 }

tests/modules/programs/darcs/defaults.nix

@@ -0,0 +1,19 @@
+{
+  programs.darcs = {
+    enable = true;
+    defaults = ''
+      ALL ignore-times
+      send sign-as AAAAAAAAAAAAAAAA
+      push prehook darcs-hooks run pre-push
+    '';
+  };
+
+  nmt.script = ''
+    assertFileContent home-files/.darcs/defaults \
+      ${builtins.toFile "expected-defaults" ''
+        ALL ignore-times
+        send sign-as AAAAAAAAAAAAAAAA
+        push prehook darcs-hooks run pre-push
+      ''}
+  '';
+}