Use WeakOutput in OutputUserData

There is no need for this to hold a strong reference to the `Output`.

Presumably `WlOutputData` is freed when the global is removed, so it is
correct to hold a strong reference there.

src/wayland/output/handlers.rs

@@ -41,7 +41,7 @@ where
         let output = data_init.init(
             resource,
             OutputUserData {
-                output: global_data.output.clone(),
+                output: global_data.output.downgrade(),
                 last_client_scale: AtomicU32::new(client_scale.load(Ordering::Acquire)),
                 client_scale,
             },
@@ -124,13 +124,14 @@ where
         output: &WlOutput,
         data: &OutputUserData,
     ) {
-        data.output
-            .inner
-            .0
-            .lock()
-            .unwrap()
-            .instances
-            .retain(|o| o.id() != output.id());
+        if let Some(o) = data.output.upgrade() {
+            o.inner
+                .0
+                .lock()
+                .unwrap()
+                .instances
+                .retain(|o| o.id() != output.id());
+        }
     }
 }
 

src/wayland/output/mod.rs

@@ -78,7 +78,7 @@ use std::sync::{
     Arc,
 };
 
-use crate::output::{Inner, Mode, Output, Scale, Subpixel};
+use crate::output::{Inner, Mode, Output, Scale, Subpixel, WeakOutput};
 
 use tracing::info;
 use wayland_protocols::xdg::xdg_output::zv1::server::zxdg_output_manager_v1::ZxdgOutputManagerV1;
@@ -144,7 +144,7 @@ impl OutputManagerState {
 /// User data for WlOutput
 #[derive(Debug)]
 pub struct OutputUserData {
-    pub(crate) output: Output,
+    pub(crate) output: WeakOutput,
     last_client_scale: AtomicU32,
     client_scale: Arc<AtomicU32>,
 }
@@ -209,7 +209,7 @@ impl Output {
 
     /// Attempt to retrieve a [`Output`] from an existing resource
     pub fn from_resource(output: &WlOutput) -> Option<Output> {
-        output.data::<OutputUserData>().map(|ud| ud.output.clone())
+        output.data::<OutputUserData>().and_then(|ud| ud.output.upgrade())
     }
 
     pub(crate) fn wl_change_current_state(