output: store a weak ref in the global to avoid...

...a cycle keeping the output alive indefinitely

src/output.rs

@@ -254,6 +254,7 @@ pub struct WeakOutput {
 
 /// Data of an Output
 pub(crate) type OutputData = Arc<(Mutex<Inner>, UserDataMap)>;
+pub(crate) type WeakOutputData = Weak<(Mutex<Inner>, UserDataMap)>;
 
 impl Output {
     /// Create a new output with given name and physical properties.

src/wayland/output/handlers.rs

@@ -38,7 +38,13 @@ where
         data_init: &mut DataInit<'_, D>,
     ) {
         let client_scale = state.client_compositor_state(client).clone_client_scale();
-        let output = data_init.init(
+
+        let Some(output) = global_data.inner.upgrade().map(|inner| Output { inner }) else {
+            tracing::warn!("trying to bind a destroyed output, forgot to disable a output global?");
+            return;
+        };
+
+        let wl_output = data_init.init(
             resource,
             OutputUserData {
                 global_data: global_data.inner.clone(),
@@ -47,7 +53,7 @@ where
             },
         );
 
-        let mut inner = global_data.inner.0.lock().unwrap();
+        let mut inner = output.inner.0.lock().unwrap();
 
         let span = warn_span!("output_bind", name = inner.name);
         let _enter = span.enter();
@@ -64,7 +70,7 @@ where
             warn!("Output is used with not preferred mode set");
         }
 
-        inner.send_geometry_to(&output);
+        inner.send_geometry_to(&wl_output);
 
         for &mode in &inner.modes {
             let mut flags = WMode::empty();
@@ -74,35 +80,32 @@ where
             if Some(mode) == inner.preferred_mode {
                 flags |= WMode::Preferred;
             }
-            output.mode(flags, mode.size.w, mode.size.h, mode.refresh);
+            wl_output.mode(flags, mode.size.w, mode.size.h, mode.refresh);
         }
 
-        if output.version() >= 4 {
-            output.name(inner.name.clone());
-            output.description(inner.description.clone())
+        if wl_output.version() >= 4 {
+            wl_output.name(inner.name.clone());
+            wl_output.description(inner.description.clone())
         }
 
-        if output.version() >= 2 {
-            output.scale(inner.scale.integer_scale());
-            output.done();
+        if wl_output.version() >= 2 {
+            wl_output.scale(inner.scale.integer_scale());
+            wl_output.done();
         }
 
         // Send enter for surfaces already on this output.
         for surface in &inner.surfaces {
             if let Ok(surface) = surface.upgrade() {
                 if surface.client().as_ref() == Some(client) {
-                    surface.enter(&output);
+                    surface.enter(&wl_output);
                 }
             }
         }
 
-        inner.instances.push(output.downgrade());
+        inner.instances.push(wl_output.downgrade());
 
         drop(inner);
-        let o = Output {
-            inner: global_data.inner.clone(),
-        };
-        state.output_bound(o, output);
+        state.output_bound(output, wl_output);
     }
 }
 
@@ -124,15 +127,18 @@ where
     fn destroyed(
         _state: &mut D,
         _client_id: wayland_server::backend::ClientId,
-        output: &WlOutput,
+        wl_output: &WlOutput,
         data: &OutputUserData,
     ) {
-        data.global_data
+        let Some(output_data) = data.global_data.upgrade() else {
+            return;
+        };
+        output_data
             .0
             .lock()
             .unwrap()
             .instances
-            .retain(|o| o.id() != output.id());
+            .retain(|o| o.id() != wl_output.id());
     }
 }
 

src/wayland/output/mod.rs

@@ -78,7 +78,7 @@ use std::sync::{
     Arc,
 };
 
-use crate::output::{Inner, Mode, Output, OutputData, Scale, Subpixel};
+use crate::output::{Inner, Mode, Output, Scale, Subpixel, WeakOutputData};
 
 use tracing::info;
 use wayland_protocols::xdg::xdg_output::zv1::server::zxdg_output_manager_v1::ZxdgOutputManagerV1;
@@ -104,7 +104,7 @@ pub struct OutputManagerState {
 /// Internal data of a wl_output global
 #[derive(Debug)]
 pub struct WlOutputData {
-    inner: OutputData,
+    inner: WeakOutputData,
 }
 
 /// Events initiated by the clients interacting with outputs
@@ -144,7 +144,7 @@ impl OutputManagerState {
 /// User data for WlOutput
 #[derive(Debug)]
 pub struct OutputUserData {
-    pub(crate) global_data: OutputData,
+    pub(crate) global_data: WeakOutputData,
     last_client_scale: AtomicU32,
     client_scale: Arc<AtomicU32>,
 }
@@ -207,16 +207,17 @@ impl Output {
         display.create_global::<D, WlOutput, _>(
             4,
             WlOutputData {
-                inner: self.inner.clone(),
+                inner: Arc::downgrade(&self.inner),
             },
         )
     }
 
     /// Attempt to retrieve a [`Output`] from an existing resource
     pub fn from_resource(output: &WlOutput) -> Option<Output> {
-        output.data::<OutputUserData>().map(|ud| Output {
-            inner: ud.global_data.clone(),
-        })
+        output
+            .data::<OutputUserData>()
+            .and_then(|ud| ud.global_data.upgrade())
+            .map(|inner| Output { inner })
     }
 
     pub(crate) fn wl_change_current_state(