Use the existing user D-Bus session bus instead of spawning dbus-launch

cinnamon-session/main.c

@@ -162,11 +162,23 @@ require_dbus_session (int      argc,
                       GError **error)
 {
         char **new_argv;
+        char  *address;
         int    i;
 
         if (g_getenv ("DBUS_SESSION_BUS_ADDRESS"))
                 return TRUE;
 
+        /* Use the bus the user session already has (GDBus looks for the
+         * well-known socket at $XDG_RUNTIME_DIR/bus), rather than starting a
+         * second one that activated services and portals would be split
+         * across.  Exporting the address keeps all our children on it. */
+        address = g_dbus_address_get_for_bus_sync (G_BUS_TYPE_SESSION, NULL, NULL);
+        if (address != NULL) {
+                g_setenv ("DBUS_SESSION_BUS_ADDRESS", address, TRUE);
+                g_free (address);
+                return TRUE;
+        }
+
         /* Just a sanity check to prevent infinite recursion if
          * dbus-launch fails to set DBUS_SESSION_BUS_ADDRESS 
          */
@@ -183,17 +195,15 @@ require_dbus_session (int      argc,
 	}
         new_argv[i + 2] = NULL;
 
-        if (!execvp ("dbus-launch", new_argv)) {
-                g_set_error (error, 
-                             G_SPAWN_ERROR,
-                             G_SPAWN_ERROR_FAILED,
-                             "No session bus and could not exec dbus-launch: %s",
-                             g_strerror (errno));
-                return FALSE;
-        }
-
-        /* Should not be reached */
-        return TRUE;
+        /* execvp() only returns on failure */
+        execvp ("dbus-launch", new_argv);
+
+        g_set_error (error,
+                     G_SPAWN_ERROR,
+                     G_SPAWN_ERROR_FAILED,
+                     "No session bus and could not exec dbus-launch: %s",
+                     g_strerror (errno));
+        return FALSE;
 }
 
 /* Whether ~/.xinputrc (written by im-config / mintlocale-im) selects fcitx5.

debian/control

@@ -8,7 +8,7 @@ Build-Depends:
  libcanberra-dev,
  libcinnamon-desktop-dev (>= 6.0),
  libgl-dev,
- libglib2.0-dev (>= 2.37.3),
+ libglib2.0-dev (>= 2.50.0),
  libgtk-3-dev (>= 3.0.0),
  libice-dev,
  libpango1.0-dev,

meson.build

@@ -28,9 +28,9 @@
 ################################################################################
 # Dependencies
 
-gio         = dependency('gio-2.0')
+gio         = dependency('gio-2.0',     version: '>=2.50.0')
 gtk3        = dependency('gtk+-3.0',    version: '>=3.0.0')
-glib        = dependency('glib-2.0',    version: '>=2.37.3')
+glib        = dependency('glib-2.0',    version: '>=2.50.0')
 libcanberra = dependency('libcanberra')
 pango       = dependency('pango')
 pangoxft    = dependency('pangoxft', required: false)
@@ -136,7 +136,7 @@
 conf.set('ENABLE_IPV6', have_ipv6)
 
 ################################################################################
 # Additionnal flags
 
 rootInclude = include_directories('.')