remove FutureId.assign_existing

wgpu-core/src/device/global.rs

@@ -834,20 +834,6 @@ impl Global {
                 Err(e) => break 'error e,
             };
 
-            // Currently we make a distinction between fid.assign and fid.assign_existing. This distinction is incorrect,
-            // but see https://github.com/gfx-rs/wgpu/issues/4912.
-            //
-            // `assign` also registers the ID with the resource info, so it can be automatically reclaimed. This needs to
-            // happen with a mutable reference, which means it can only happen on creation.
-            //
-            // Because we need to call `assign` inside the closure (to get mut access), we need to "move" the future id into the closure.
-            // Rust cannot figure out at compile time that we only ever consume the ID once, so we need to move the check
-            // to runtime using an Option.
-            let mut fid = Some(fid);
-
-            // The closure might get called, and it might give us an ID. Side channel it out of the closure.
-            let mut id = None;
-
             let bgl_result = device.bgl_pool.get_or_init(entry_map, |entry_map| {
                 let bgl =
                     device.create_bind_group_layout(&desc.label, entry_map, bgl::Origin::Pool)?;
@@ -856,8 +842,6 @@ impl Global {
                     .unwrap();
 
                 let bgl = Arc::new(bgl);
-                let id_inner = fid.take().unwrap().assign(bgl.clone());
-                id = Some(id_inner);
 
                 Ok(bgl)
             });
@@ -867,16 +851,10 @@ impl Global {
                 Err(e) => break 'error e,
             };
 
-            // If the ID was not assigned, and we survived the above check,
+            let id = fid.assign(layout.clone());
-            // it means that the bind group layout already existed and we need to call `assign_existing`.
-            //
-            // Calling this function _will_ leak the ID. See https://github.com/gfx-rs/wgpu/issues/4912.
-            if id.is_none() {
-                id = Some(fid.take().unwrap().assign_existing(&layout))
-            }
 
             api_log!("Device::create_bind_group_layout -> {id:?}");
-            return (id.unwrap(), None);
+            return (id, None);
         };
 
         let fid = hub.bind_group_layouts.prepare(id_in);
@@ -1705,7 +1683,7 @@ impl Global {
                 Err(_) => break 'error binding_model::GetBindGroupLayoutError::InvalidPipeline,
             };
             let id = match pipeline.layout.bind_group_layouts.get(index as usize) {
-                Some(bg) => hub.bind_group_layouts.prepare(id_in).assign_existing(bg),
+                Some(bg) => hub.bind_group_layouts.prepare(id_in).assign(bg.clone()),
                 None => {
                     break 'error binding_model::GetBindGroupLayoutError::InvalidGroupIndex(index)
                 }
@@ -1906,7 +1884,7 @@ impl Global {
             };
 
             let id = match pipeline.layout.bind_group_layouts.get(index as usize) {
-                Some(bg) => hub.bind_group_layouts.prepare(id_in).assign_existing(bg),
+                Some(bg) => hub.bind_group_layouts.prepare(id_in).assign(bg.clone()),
                 None => {
                     break 'error binding_model::GetBindGroupLayoutError::InvalidGroupIndex(index)
                 }

wgpu-core/src/registry.rs

@@ -82,16 +82,6 @@ impl<T: StorageItem> FutureId<'_, T> {
         self.id
     }
 
-    /// Assign an existing resource to a new ID.
-    ///
-    /// Registers it with the registry.
-    pub fn assign_existing(self, value: &Arc<T>) -> Id<T::Marker> {
-        let mut data = self.data.write();
-        debug_assert!(!data.contains(self.id));
-        data.insert(self.id, value.clone());
-        self.id
-    }
-
     pub fn assign_error(self) -> Id<T::Marker> {
         self.data.write().insert_error(self.id);
         self.id

wgpu-core/src/storage.rs

@@ -80,18 +80,6 @@ impl<T> Storage<T>
 where
     T: StorageItem,
 {
-    #[allow(dead_code)]
-    pub(crate) fn contains(&self, id: Id<T::Marker>) -> bool {
-        let (index, epoch, _) = id.unzip();
-        match self.map.get(index as usize) {
-            Some(&Element::Vacant) => false,
-            Some(&Element::Occupied(_, storage_epoch) | &Element::Error(storage_epoch)) => {
-                storage_epoch == epoch
-            }
-            None => false,
-        }
-    }
-
     /// Get a reference to an item behind a potentially invalid ID.
     /// Panics if there is an epoch mismatch, or the entry is empty.
     pub(crate) fn get(&self, id: Id<T::Marker>) -> Result<&Arc<T>, InvalidId> {