From 6dc68b1d16c47031cf897eb0b0aa2fcce4178baf Mon Sep 17 00:00:00 2001
From: Nicolas Berbiche <nic.berbiche@gmail.com>
Date: Sun, 15 Nov 2020 17:58:55 -0500
Subject: [PATCH] i3: validate configuration at build time

PR #1579
---
 modules/services/window-managers/i3-sway/i3.nix | 17 ++++++++++++++++-
 .../window-managers/i3/i3-followmouse.nix       |  4 +++-
 .../window-managers/i3/i3-keybindings.nix       |  7 ++++---
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/modules/services/window-managers/i3-sway/i3.nix b/modules/services/window-managers/i3-sway/i3.nix
index 8cc01cd6..37f6e8bd 100644
--- a/modules/services/window-managers/i3-sway/i3.nix
+++ b/modules/services/window-managers/i3-sway/i3.nix
@@ -193,6 +193,21 @@ let
   else
     "") + "\n" + cfg.extraConfig);
 
+  # Validates the i3 configuration
+  checkI3Config =
+    pkgs.runCommandLocal "i3-config" { buildInputs = [ cfg.package ]; } ''
+      # We have to make sure the wrapper does not start a dbus session
+      export DBUS_SESSION_BUS_ADDRESS=1
+
+      # A zero exit code means i3 succesfully validated the configuration
+      i3 -c ${configFile} -C -d all || {
+        echo "i3 configuration validation failed"
+        echo "For a verbose log of the failure, run 'i3 -c ${configFile} -C -d all'"
+        exit 1
+      };
+      cp ${configFile} $out
+    '';
+
 in {
   options = {
     xsession.windowManager.i3 = {
@@ -229,7 +244,7 @@ in {
       home.packages = [ cfg.package ];
       xsession.windowManager.command = "${cfg.package}/bin/i3";
       xdg.configFile."i3/config" = {
-        source = configFile;
+        source = checkI3Config;
         onChange = ''
           i3Socket=''${XDG_RUNTIME_DIR:-/run/user/$UID}/i3/ipc-socket.*
           if [ -S $i3Socket ]; then
diff --git a/tests/modules/services/window-managers/i3/i3-followmouse.nix b/tests/modules/services/window-managers/i3/i3-followmouse.nix
index 8d51e348..43e15cda 100644
--- a/tests/modules/services/window-managers/i3/i3-followmouse.nix
+++ b/tests/modules/services/window-managers/i3/i3-followmouse.nix
@@ -14,7 +14,9 @@ with lib;
       (self: super: {
         dmenu = super.dmenu // { outPath = "@dmenu@"; };
 
-        i3 = super.i3 // { outPath = "@i3@"; };
+        i3 = super.writeScriptBin "i3" "" // { outPath = "@i3@"; };
+
+        i3-gaps = super.writeScriptBin "i3" "" // { outPath = "@i3-gaps@"; };
 
         i3status = super.i3status // { outPath = "@i3status@"; };
       })
diff --git a/tests/modules/services/window-managers/i3/i3-keybindings.nix b/tests/modules/services/window-managers/i3/i3-keybindings.nix
index 4f8515e6..0458b874 100644
--- a/tests/modules/services/window-managers/i3/i3-keybindings.nix
+++ b/tests/modules/services/window-managers/i3/i3-keybindings.nix
@@ -19,9 +19,10 @@ with lib;
     nixpkgs.overlays = [
       (self: super: {
         dmenu = super.dmenu // { outPath = "@dmenu@"; };
-
-        i3 = super.i3 // { outPath = "@i3@"; };
-
+        i3 = super.writeScriptBin "i3" "" // { outPath = "@i3@"; };
+        i3-gaps = super.writeScriptBin "i3-gaps" "" // {
+          outPath = "@i3-gaps@";
+        };
         i3status = super.i3status // { outPath = "@i3status@"; };
       })
     ];