From a9b0b4e7f7a51db77df0ca75c7029d7b60daa369 Mon Sep 17 00:00:00 2001
From: charlotte <charlotte.c.mcelwain@gmail.com>
Date: Fri, 11 Apr 2025 16:18:26 -0700
Subject: [PATCH] Mark render assets as modified when removed from the asset
 server (#18814)

# Objective

Fixes #18808

## Solution

When an asset emits a removed event, mark it as modified in the render
world to ensure any appropriate bookkeeping runs as necessary.
---
 crates/bevy_render/src/render_asset.rs | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/crates/bevy_render/src/render_asset.rs b/crates/bevy_render/src/render_asset.rs
index 6626cb7797..0568b40391 100644
--- a/crates/bevy_render/src/render_asset.rs
+++ b/crates/bevy_render/src/render_asset.rs
@@ -246,10 +246,6 @@ pub(crate) fn extract_render_asset<A: RenderAsset>(
             let mut modified = <HashSet<_>>::default();
 
             for event in events.read() {
-                #[expect(
-                    clippy::match_same_arms,
-                    reason = "LoadedWithDependencies is marked as a TODO, so it's likely this will no longer lint soon."
-                )]
                 match event {
                     AssetEvent::Added { id } => {
                         needs_extracting.insert(*id);
@@ -258,9 +254,20 @@ pub(crate) fn extract_render_asset<A: RenderAsset>(
                         needs_extracting.insert(*id);
                         modified.insert(*id);
                     }
-                    AssetEvent::Removed { .. } => {
-                        // We don't care that the asset was removed from Assets<T> in the main world.
-                        // An asset is only removed from RenderAssets<T> when its last handle is dropped (AssetEvent::Unused).
+                    AssetEvent::Removed { id, .. } => {
+                        // Normally, we consider an asset removed from the render world only
+                        // when it's final handle is dropped triggering an `AssetEvent::Unused`
+                        // event. However, removal without unused can happen when the asset
+                        // is explicitly removed from the asset server and re-added by the user.
+                        // We mark the asset as modified in this case to ensure that
+                        // any necessary render world bookkeeping still runs.
+
+                        // TODO: consider removing this check and just emitting Unused after
+                        // Removed to ensure that the asset is always "really" removed from the
+                        // render world when the last strong handle is dropped.
+                        if !removed.contains(id) {
+                            modified.insert(*id);
+                        }
                     }
                     AssetEvent::Unused { id } => {
                         needs_extracting.remove(id);