From e1dee4efcbffc72260025078bf8297a3b732509c Mon Sep 17 00:00:00 2001
From: Silvan Mosberger <infinisil@icloud.com>
Date: Fri, 6 Apr 2018 18:51:10 +0200
Subject: [PATCH] lib: make extensible

This allows the lib fixed point to be extended with

  myLib = lib.extend (self: super: {
    foo = "foo";
  })

With this it's possible to have the new modified lib attrset available to all
modules when using evalModules

  myLib.evalModules {
    modules = [ ({ lib, ... }: {
      options.bar = lib.mkOption {
	default = lib.foo;
      };
    }) ];
  }

  => { config = { bar = "foo"; ... }; options = ...; }
---
 lib/default.nix | 8 +++++---
 lib/modules.nix | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/lib/default.nix b/lib/default.nix
index cbe0a0ba21b..59b3d2159da 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -5,9 +5,11 @@
  */
 let
 
-  callLibs = file: import file { inherit lib; };
+  inherit (import ./fixed-points.nix {}) makeExtensible;
 
-  lib = rec {
+  lib = makeExtensible (self: let
+    callLibs = file: import file { lib = self; };
+  in with self; {
 
     # often used, or depending on very little
     trivial = callLibs ./trivial.nix;
@@ -128,5 +130,5 @@ let
       mergeAttrsNoOverride mergeAttrByFunc mergeAttrsByFuncDefaults
       mergeAttrsByFuncDefaultsClean mergeAttrBy
       prepareDerivationArgs nixType imap overridableDelayableArgs;
-  };
+  });
 in lib
diff --git a/lib/modules.nix b/lib/modules.nix
index acd07f732bd..4ef982c7ec9 100644
--- a/lib/modules.nix
+++ b/lib/modules.nix
@@ -59,7 +59,7 @@ rec {
         };
       };
 
-      closed = closeModules (modules ++ [ internalModule ]) ({ inherit config options; lib = import ./.; } // specialArgs);
+      closed = closeModules (modules ++ [ internalModule ]) ({ inherit config options lib; } // specialArgs);
 
       options = mergeModules prefix (reverseList (filterModules (specialArgs.modulesPath or "") closed));