Restore ability to call g_object_new (XDP_TYPE_PORTAL, ...)

Calling `g_object_new()` for an XdpPortal used to work before 0.7, but no longer sets up the GDBusConnection, making most method calls fail with `assertion 'G_IS_DBUS_CONNECTION (connection)' failed`. This makes #119 an incompatible change. In particular, the GTK 4 test app calls `new Xdp.Portal()`, which is a JavaScript binding for `g_object_new()` and fails in this way. GObject documentation suggests that bindings should automatically detect types that implement GInitable and call GInitable.init in the higher-level language's constructor, but it seems that neither gjs nor pygobject actually does this. Mostly preserve previous functionality by moving the actual initialization back to the GObject instance init function, and making the GInitable init function just report a pre-existing error if any. Signed-off-by: Simon McVittie <[email protected]>
flatpak · Sep 8, 2023 · f68e30a · f68e30a
1 parent fcfd10a
commit f68e30a
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Showing 2 changed files with 26 additions and 14 deletions.
diff --git a/libportal/portal-private.h b/libportal/portal-private.h
@@ -25,6 +25,7 @@
 struct _XdpPortal {
   GObject parent_instance;
 
+  GError *init_error;
   GDBusConnection *bus;
   char *sender;
 

diff --git a/libportal/portal.c b/libportal/portal.c
@@ -80,6 +80,8 @@ xdp_portal_finalize (GObject *object)
 {
   XdpPortal *portal = XDP_PORTAL (object);
 
+  g_clear_error (&portal->init_error);
+
   /* inhibit */
   if (portal->inhibit_handles)
     g_hash_table_unref (portal->inhibit_handles);
@@ -293,30 +295,44 @@ create_bus_from_address (const char *address,
   return g_steal_pointer (&bus);
 }
 
-static gboolean
-xdp_portal_initable_init (GInitable     *initable,
-                          GCancellable  *cancellable,
-                          GError       **out_error)
+/* Historically, g_object_new() on an XdpPortal initialized it. We follow
+ * that here by doing the actual initialization early, and only dealing
+ * with the result in initable_init(). */
+static void
+xdp_portal_init (XdpPortal *portal)
 {
   int i;
 
-  XdpPortal *portal = (XdpPortal*) initable;
-
   /* g_bus_get_sync() returns a singleton. In the test suite we may restart
    * the session bus, so we have to manually connect to the new bus */
   if (getenv ("LIBPORTAL_TEST_SUITE"))
-    portal->bus = create_bus_from_address (getenv ("DBUS_SESSION_BUS_ADDRESS"), out_error);
+    portal->bus = create_bus_from_address (getenv ("DBUS_SESSION_BUS_ADDRESS"), &portal->init_error);
   else
-    portal->bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, out_error);
+    portal->bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, &portal->init_error);
 
   if (portal->bus == NULL)
-    return FALSE;
+    return;
 
   portal->sender = g_strdup (g_dbus_connection_get_unique_name (portal->bus) + 1);
   for (i = 0; portal->sender[i]; i++)
     if (portal->sender[i] == '.')
       portal->sender[i] = '_';
+}
 
+static gboolean
+xdp_portal_initable_init (GInitable     *initable,
+                          GCancellable  *cancellable,
+                          GError       **out_error)
+{
+  XdpPortal *portal = (XdpPortal*) initable;
+
+  if (portal->init_error != NULL)
+    {
+      g_propagate_error (out_error, g_error_copy (portal->init_error));
+      return FALSE;
+    }
+
+  g_assert (portal->bus != NULL);
   return TRUE;
 }
 
@@ -326,11 +342,6 @@ xdp_portal_initable_iface_init (GInitableIface *iface)
   iface->init = xdp_portal_initable_init;
 }
 
-static void
-xdp_portal_init (XdpPortal *portal)
-{
-}
-
 /**
  * xdp_portal_initable_new:
  * @error: A GError location to store the error occurring, or NULL to ignore.