Merge pull request #6272 from NixOS/types-path-better-error

types.nix: better error message for non-paths
2015-08-15 13:16:00 +02:00
parent 77250457bc 691f683c8c
commit e6f1e1e5db
2 changed files with 3 additions and 2 deletions
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -103,7 +103,8 @@ rec {
    path = mkOptionType {
      name = "path";
      # Hacky: there is no ‘isPath’ primop.
-      check = x: builtins.substring 0 1 (toString x) == "/";
+      # need to check isString first because otherwise toString throws an error.
+      check = x: builtins.isString x && builtins.substring 0 1 (toString x) == "/";
      merge = mergeOneOption;
    };