Hot reload labeled assets whose source asset is not loaded

crates/bevy_asset/src/server/info.rs

@@ -69,6 +69,9 @@ pub(crate) struct AssetInfos {
  /// Tracks assets that depend on the "key" asset path inside their asset loaders ("loader dependencies")
  /// This should only be set when watching for changes to avoid unnecessary work.
  pub(crate) loader_dependants: HashMap<AssetPath<'static>, HashSet<AssetPath<'static>>>,
+ /// Tracks living labeled assets for a given source asset.
+ /// This should only be set when watching for changes to avoid unnecessary work.
+ pub(crate) living_labeled_assets: HashMap<AssetPath<'static>, HashSet<String>>,
  pub(crate) handle_providers: HashMap<TypeId, AssetHandleProvider>,
  pub(crate) dependency_loaded_event_sender: HashMap<TypeId, fn(&mut World, UntypedAssetId)>,
 }
@@ -88,6 +91,8 @@ impl AssetInfos {
  Self::create_handle_internal(
  &mut self.infos,
  &self.handle_providers,
+ &mut self.living_labeled_assets,
+ self.watching_for_changes,
  TypeId::of::<A>(),
  None,
  None,
@@ -107,6 +112,8 @@ impl AssetInfos {
  Self::create_handle_internal(
  &mut self.infos,
  &self.handle_providers,
+ &mut self.living_labeled_assets,
+ self.watching_for_changes,
  type_id,
  None,
  None,
@@ -116,9 +123,12 @@ impl AssetInfos {
  )
  }
 
+ #[allow(clippy::too_many_arguments)]
  fn create_handle_internal(
  infos: &mut HashMap<UntypedAssetId, AssetInfo>,
  handle_providers: &HashMap<TypeId, AssetHandleProvider>,
+ living_labeled_assets: &mut HashMap<AssetPath<'static>, HashSet<String>>,
+ watching_for_changes: bool,
  type_id: TypeId,
  path: Option<AssetPath<'static>>,
  meta_transform: Option<MetaTransform>,
@@ -128,6 +138,16 @@ impl AssetInfos {
  .get(&type_id)
  .ok_or(MissingHandleProviderError(type_id))?;
 
+ if watching_for_changes {
+ if let Some(path) = &path {
+ let mut without_label = path.to_owned();
+ if let Some(label) = without_label.remove_label() {
+ let labels = living_labeled_assets.entry(without_label).or_default();
+ labels.insert(label.to_string());
+ }
+ }
+ }
+
  let handle = provider.reserve_handle_internal(true, path.clone(), meta_transform);
  let mut info = AssetInfo::new(Arc::downgrade(&handle), path);
  if loading {
@@ -136,6 +156,7 @@ impl AssetInfos {
  info.rec_dep_load_state = RecursiveDependencyLoadState::Loading;
  }
  infos.insert(handle.id, info);
+
  Ok(UntypedHandle::Strong(handle))
  }
 
@@ -226,6 +247,8 @@ impl AssetInfos {
  let handle = Self::create_handle_internal(
  &mut self.infos,
  &self.handle_providers,
+ &mut self.living_labeled_assets,
+ self.watching_for_changes,
  type_id,
  Some(path),
  meta_transform,
@@ -256,7 +279,7 @@ impl AssetInfos {
  Some(UntypedHandle::Strong(strong_handle))
  }
 
- /// Returns `true` if this path has
+ /// Returns `true` if the asset this path points to is still alive
  pub(crate) fn is_path_alive(&self, path: &AssetPath) -> bool {
  if let Some(id) = self.path_to_id.get(path) {
  if let Some(info) = self.infos.get(id) {
@@ -266,12 +289,26 @@ impl AssetInfos {
  false
  }
 
+ /// Returns `true` if the asset at this path should be reloaded
+ pub(crate) fn should_reload(&self, path: &AssetPath) -> bool {
+ if self.is_path_alive(path) {
+ return true;
+ }
+
+ if let Some(living) = self.living_labeled_assets.get(path) {
+ !living.is_empty()
+ } else {
+ false
+ }
+ }
+
  // Returns `true` if the asset should be removed from the collection
  pub(crate) fn process_handle_drop(&mut self, id: UntypedAssetId) -> bool {
  Self::process_handle_drop_internal(
  &mut self.infos,
  &mut self.path_to_id,
  &mut self.loader_dependants,
+ &mut self.living_labeled_assets,
  self.watching_for_changes,
  id,
  )
@@ -520,6 +557,7 @@ impl AssetInfos {
  infos: &mut HashMap<UntypedAssetId, AssetInfo>,
  path_to_id: &mut HashMap<AssetPath<'static>, UntypedAssetId>,
  loader_dependants: &mut HashMap<AssetPath<'static>, HashSet<AssetPath<'static>>>,
+ living_labeled_assets: &mut HashMap<AssetPath<'static>, HashSet<String>>,
  watching_for_changes: bool,
  id: UntypedAssetId,
  ) -> bool {
@@ -539,6 +577,18 @@ impl AssetInfos {
  dependants.remove(&path);
  }
  }
+ if let Some(label) = path.label() {
+ let mut without_label = path.to_owned();
+ without_label.remove_label();
+ if let Entry::Occupied(mut entry) =
+ living_labeled_assets.entry(without_label)
+ {
+ entry.get_mut().remove(label);
+ if entry.get().is_empty() {
+ entry.remove();
+ }
+ };
+ }
  }
  path_to_id.remove(&path);
  }
@@ -565,6 +615,7 @@ impl AssetInfos {
  &mut self.infos,
  &mut self.path_to_id,
  &mut self.loader_dependants,
+ &mut self.living_labeled_assets,
  self.watching_for_changes,
  id.untyped(provider.type_id),
  );

crates/bevy_asset/src/server/mod.rs

@@ -394,7 +394,7 @@ impl AssetServer {
  let owned_path = path.to_owned();
  IoTaskPool::get()
  .spawn(async move {
- if server.data.infos.read().is_path_alive(&owned_path) {
+ if server.data.infos.read().should_reload(&owned_path) {
  info!("Reloading {owned_path} because it has changed");
  if let Err(err) = server.load_internal(None, owned_path, true, None).await {
  error!("{}", err);