core: cleanup environment on exit (#5941)

src/Compositor.cpp

@@ -341,6 +341,28 @@ void CCompositor::removeAllSignals() {
         removeWLSignal(&Events::listen_sessionActive);
 }
 
+void CCompositor::cleanEnvironment() {
+    // in compositor constructor
+    unsetenv("WAYLAND_DISPLAY");
+    // in startCompositor
+    unsetenv("HYPRLAND_INSTANCE_SIGNATURE");
+
+    // in main
+    unsetenv("HYPRLAND_CMD");
+    unsetenv("XDG_BACKEND");
+    unsetenv("XDG_CURRENT_DESKTOP");
+
+    if (m_sWLRSession) {
+        const auto CMD =
+#ifdef USES_SYSTEMD
+            "systemctl --user unset-environment DISPLAY WAYLAND_DISPLAY HYPRLAND_INSTANCE_SIGNATURE XDG_CURRENT_DESKTOP QT_QPA_PLATFORMTHEME && hash "
+            "dbus-update-activation-environment 2>/dev/null && "
+#endif
+            "dbus-update-activation-environment --systemd WAYLAND_DISPLAY XDG_CURRENT_DESKTOP HYPRLAND_INSTANCE_SIGNATURE QT_QPA_PLATFORMTHEME";
+        g_pKeybindManager->spawn(CMD);
+    }
+}
+
 void CCompositor::cleanup() {
     if (!m_sWLDisplay || m_bIsShuttingDown)
         return;
@@ -358,6 +380,8 @@ void CCompositor::cleanup() {
         Systemd::SdNotify(0, "STOPPING=1");
 #endif
 
+    cleanEnvironment();
+
     // unload all remaining plugins while the compositor is
     // still in a normal working state.
     g_pPluginSystem->unloadAllPlugins();

src/Compositor.hpp

@@ -191,6 +191,7 @@ class CCompositor {
   private:
     void     initAllSignals();
     void     removeAllSignals();
+    void     cleanEnvironment();
     void     setRandomSplash();
     void     initManagers(eManagersInitStage stage);
     void     prepareFallbackOutput();

src/managers/XWaylandManager.cpp

@@ -27,7 +27,11 @@ CHyprXWaylandManager::CHyprXWaylandManager() {
 #endif
 }
 
-CHyprXWaylandManager::~CHyprXWaylandManager() {}
+CHyprXWaylandManager::~CHyprXWaylandManager() {
+#ifndef NO_XWAYLAND
+    unsetenv("DISPLAY");
+#endif
+}
 
 wlr_surface* CHyprXWaylandManager::getWindowSurface(PHLWINDOW pWindow) {
     if (pWindow->m_bIsX11)