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WpObjectManager objects-changed signal not always emitted

The objects-changed signal in ObjectManager should fire after objects have been added/removed, but it does not in practice.

Occurs on some wireplumber startupts, with visible effects in m-default-nodes.

Some extra debug:

diff --git a/modules/module-default-nodes.c b/modules/module-default-nodes.c
index 0fdaed5..454c4b0 100644
--- a/modules/module-default-nodes.c
+++ b/modules/module-default-nodes.c
@@ -554,6 +554,8 @@ on_object_added (WpObjectManager *om, WpPipewireObject *proxy, gpointer d)
 {
   WpDefaultNodes * self = WP_DEFAULT_NODES (d);
 
+  wp_debug_object (om, "object-added signal");
+
   if (WP_IS_DEVICE (proxy)) {
     g_signal_connect_object (proxy, "params-changed",
         G_CALLBACK (schedule_rescan), self, G_CONNECT_SWAPPED);

Then, WIREPLUMBER_DEBUG=5 wireplumber and grepping for the address of the objectmanager for m-default-nodes:

<< ... >>
T 22:04:06.566114  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:729:wp_object_manager_add_object: <WpObjectManager:0x61d000010b20> added: <WpPort:0x6250014d5740>
D 22:04:06.566127    m-default-nodes ../subprojects/wireplumber/modules/module-default-nodes.c:557:on_object_added: <WpObjectManager:0x61d000010b20> object-added signal
T 22:04:06.566140  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:4 changed:1 idle_source:(nil) installed:1
T 22:04:06.571665  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:4 changed:1 idle_source:(nil) installed:1
T 22:04:06.572270  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:4 changed:1 idle_source:(nil) installed:1
T 22:04:06.575925  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:4 changed:1 idle_source:(nil) installed:1
T 22:04:06.576546  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:4 changed:1 idle_source:(nil) installed:1
T 22:04:06.580483  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:4 changed:1 idle_source:(nil) installed:1
T 22:04:06.581055  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:4 changed:1 idle_source:(nil) installed:1
T 22:04:09.232080  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:787:wp_object_manager_add_global: <WpObjectManager:0x61d000010b20> adding global:57 -> <WpClient:0x6250014d5840>
T 22:04:09.232115  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:787:wp_object_manager_add_global: <WpObjectManager:0x61d000010b20> adding global:58 -> <WpClient:0x6250014d5940>
T 22:04:09.232147  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:6 changed:1 idle_source:(nil) installed:1
T 22:04:09.235396  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:5 changed:1 idle_source:(nil) installed:1
T 22:04:09.235537  wp-object-manager ../subprojects/wireplumber/lib/wp/object-manager.c:675:wp_object_manager_maybe_objects_changed: <WpObjectManager:0x61d000010b20> pending:4 changed:1 idle_source:(nil) installed:1
<< end of log >>

So the pending_nodes counter never reaches zero, and so default nodes stop updating properly. Probably also other stuff using that signal will break.

Maybe if it's hard to fix before next release, put in some workaround like !332 (closed)

Edited by P V