nixos/gnome3: override schemas using env variable

For some reason, the GNOME 3.26 update broke the overrides. It turns
out the overrides now need to come before the overridden schemas in the
XDG_DATA_DIRS variable. This is not possible in general due to applications
prefixing the variable (e.g. in wrapGAppsHook).

To fix this, a new environment variable NIX_GSETTINGS_OVERRIDES_DIR
was introduced. It has greater priority than XDG_DATA_DIRS but lower
than GSETTINGS_SCHEMA_DIR. A separate variable was chosen in order not
to block the built-in one for users.

1 files changed, 1 insertions, 1 deletions

diff --git a/nixos/modules/services/x11/desktop-managers/gnome3.nix b/nixos/modules/services/x11/desktop-managers/gnome3.nix
index 8a87be97db0b..d2c856fc9332 100644
--- a/nixos/modules/services/x11/desktop-managers/gnome3.nix
+++ b/nixos/modules/services/x11/desktop-managers/gnome3.nix
@@ -153,7 +153,7 @@ in {
           export XDG_DATA_DIRS=$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}${mimeAppsList}/share
 
           # Override gsettings-desktop-schema
-          export XDG_DATA_DIRS=${nixos-gsettings-desktop-schemas}/share/gsettings-schemas/nixos-gsettings-overrides''${XDG_DATA_DIRS:+:}$XDG_DATA_DIRS
+          export NIX_GSETTINGS_OVERRIDES_DIR=${nixos-gsettings-desktop-schemas}/share/gsettings-schemas/nixos-gsettings-overrides/glib-2.0/schemas
 
           # Let nautilus find extensions
           export NAUTILUS_EXTENSION_DIR=${config.system.path}/lib/nautilus/extensions-3.0/