synaptic-pkexec: Do not use pkexec under Wayland; warn users instead

Co-authored-by: Boyuan Yang <byang@debian.org>

debian/control

@@ -11,7 +11,7 @@ X-Ubuntu-Use-Langpack: yes
 
 Package: synaptic
 Architecture: any
-Depends: ${shlibs:Depends}, ${misc:Depends}, hicolor-icon-theme, policykit-1
+Depends: ${shlibs:Depends}, ${misc:Depends}, hicolor-icon-theme, policykit-1, zenity
 Conflicts: menu (<< 2.1.11)
 Recommends: libgtk2-perl (>= 1:1.130), xdg-utils
 Suggests: dwww, menu, deborphan, apt-xapian-index, tasksel, software-properties-gtk

debian/synaptic-pkexec

@@ -1,2 +1,19 @@
 #!/bin/sh
-pkexec "/usr/sbin/synaptic" "$@"
+
+USING_WAYLAND=0
+if [ ! "x${WAYLAND_DISPLAY}" = "x" ]; then
+    USING_WAYLAND=1
+fi
+if [ "x${XDG_SESSION_TYPE}" = "xwayland" ]; then
+    USING_WAYLAND=1
+fi
+
+if [ "x${USING_WAYLAND}" = "x1" ]; then
+    # Running wayland; start synaptic without pkexec
+    zenity --warning --width=500 --text \
+        "You are using Wayland environment, Synaptic will continue without administrative privileges.\\n\
+To make Synaptic fully functional, please restart your session without Wayland."
+    exec "/usr/sbin/synaptic" "$@"
+else
+    pkexec "/usr/sbin/synaptic" "$@"
+fi