From 0afdb1e933b2089e7cf00df4ef1646d639f70d81 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Tue, 29 Oct 2013 13:45:30 +0100
Subject: [PATCH] Add option type "str" for unique strings

An annoying and dangerous property of "types.string" is that it merges
multiple definitions by concatenating them, which almost never
produces a sensible result.  (Those options for which it does make
sense typically should use "types.lines" instead, and things only work
because the option definitions already end in a newline.)  Of course,
you can use "types.uniq types.string", but that's rather verbose, and
inconsistent with other basic types like "types.int".

Changing the behaviour of "types.string" to be unique by default is
not an option, given the large number of options that use it.  So
instead, we now have "types.str", which is equivalent to "types.uniq
types.string".
---
 lib/types.nix | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/types.nix b/lib/types.nix
index 34d06a9144fe..8deb379c25a9 100644
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -54,6 +54,14 @@ rec {
       check = builtins.isInt;
     };
 
+    str = mkOptionType {
+      name = "string";
+      check = builtins.isString;
+      merge = mergeOneOption;
+    };
+
+    # Deprecated; should not be used because it quietly concatenates
+    # strings, which is usually not what you want.
     string = mkOptionType {
       name = "string";
       check = builtins.isString;