From b33802ca7f0675fa8f64dd0f322ab7a57e45ba6a Mon Sep 17 00:00:00 2001
From: Damien Cassou <damien@cassou.me>
Date: Mon, 1 Jun 2020 09:56:48 +0200
Subject: [PATCH] direnv: add support for nix-direnv

PR #1297
---
 modules/programs/direnv.nix                   | 12 ++++++++--
 tests/modules/programs/direnv/default.nix     |  2 ++
 tests/modules/programs/direnv/nix-direnv.nix  | 18 +++++++++++++++
 .../programs/direnv/stdlib-and-nix-direnv.nix | 23 +++++++++++++++++++
 4 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 tests/modules/programs/direnv/nix-direnv.nix
 create mode 100644 tests/modules/programs/direnv/stdlib-and-nix-direnv.nix

diff --git a/modules/programs/direnv.nix b/modules/programs/direnv.nix
index de57727f..1d1374b8 100644
--- a/modules/programs/direnv.nix
+++ b/modules/programs/direnv.nix
@@ -70,6 +70,11 @@ in {
         Whether to enable Fish integration.
       '';
     };
+
+    enableNixDirenvIntegration = mkEnableOption ''
+      <link
+          xlink:href="https://github.com/nix-community/nix-direnv">nix-direnv</link>,
+          a fast, persistent use_nix implementation for direnv'';
   };
 
   config = mkIf cfg.enable {
@@ -78,8 +83,11 @@ in {
     xdg.configFile."direnv/config.toml" =
       mkIf (cfg.config != { }) { source = configFile cfg.config; };
 
-    xdg.configFile."direnv/direnvrc" =
-      mkIf (cfg.stdlib != "") { text = cfg.stdlib; };
+    xdg.configFile."direnv/direnvrc" = let
+      text = concatStringsSep "\n" (optional (cfg.stdlib != "") cfg.stdlib
+        ++ optional cfg.enableNixDirenvIntegration
+        "source ${pkgs.nix-direnv}/share/nix-direnv/direnvrc");
+    in mkIf (text != "") { inherit text; };
 
     programs.bash.initExtra = mkIf cfg.enableBashIntegration (
       # Using mkAfter to make it more likely to appear after other
diff --git a/tests/modules/programs/direnv/default.nix b/tests/modules/programs/direnv/default.nix
index 82ad15ff..3efad2b6 100644
--- a/tests/modules/programs/direnv/default.nix
+++ b/tests/modules/programs/direnv/default.nix
@@ -1,4 +1,6 @@
 {
   direnv-bash = ./bash.nix;
+  direnv-nix-direnv = ./nix-direnv.nix;
   direnv-stdlib = ./stdlib.nix;
+  direnv-stdlib-and-nix-direnv = ./stdlib-and-nix-direnv.nix;
 }
diff --git a/tests/modules/programs/direnv/nix-direnv.nix b/tests/modules/programs/direnv/nix-direnv.nix
new file mode 100644
index 00000000..57b3907d
--- /dev/null
+++ b/tests/modules/programs/direnv/nix-direnv.nix
@@ -0,0 +1,18 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+  config = {
+    programs.bash.enable = true;
+    programs.direnv.enable = true;
+    programs.direnv.enableNixDirenvIntegration = true;
+
+    nmt.script = ''
+      assertFileExists home-files/.bashrc
+      assertFileRegex \
+        home-files/.config/direnv/direnvrc \
+        'source /nix/store/.*nix-direnv.*/share/nix-direnv/direnvrc'
+    '';
+  };
+}
diff --git a/tests/modules/programs/direnv/stdlib-and-nix-direnv.nix b/tests/modules/programs/direnv/stdlib-and-nix-direnv.nix
new file mode 100644
index 00000000..1dc22431
--- /dev/null
+++ b/tests/modules/programs/direnv/stdlib-and-nix-direnv.nix
@@ -0,0 +1,23 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let expectedContent = "something important";
+in {
+  config = {
+    programs.bash.enable = true;
+    programs.direnv.enable = true;
+    programs.direnv.enableNixDirenvIntegration = true;
+    programs.direnv.stdlib = expectedContent;
+
+    nmt.script = ''
+      assertFileExists home-files/.bashrc
+      assertFileRegex \
+        home-files/.config/direnv/direnvrc \
+        'source /nix/store/.*nix-direnv.*/share/nix-direnv/direnvrc'
+      assertFileRegex \
+        home-files/.config/direnv/direnvrc \
+        '${expectedContent}'
+    '';
+  };
+}