Make sure the mesh actually exists before we try to specialize. (#18836)

Fixes #18809
Fixes #18823

Meshes despawned in `Last` can still be in visisible entities if they
were visible as of `PostUpdate`. Sanity check that the mesh actually
exists before we specialize. We still want to unconditionally assume
that the entity is in `EntitySpecializationTicks` as its absence from
that cache would likely suggest another bug.

crates/bevy_pbr/src/material.rs

@@ -1011,6 +1011,10 @@ pub fn specialize_material_meshes<M: Material>(
             let Ok(material_asset_id) = material_instance.asset_id.try_typed::<M>() else {
                 continue;
             };
+            let Some(mesh_instance) = render_mesh_instances.render_mesh_queue_data(*visible_entity)
+            else {
+                continue;
+            };
             let entity_tick = entity_specialization_ticks.get(visible_entity).unwrap();
             let last_specialized_tick = view_specialized_material_pipeline_cache
                 .get(visible_entity)
@@ -1022,10 +1026,6 @@ pub fn specialize_material_meshes<M: Material>(
             if !needs_specialization {
                 continue;
             }
-            let Some(mesh_instance) = render_mesh_instances.render_mesh_queue_data(*visible_entity)
-            else {
-                continue;
-            };
             let Some(mesh) = render_meshes.get(mesh_instance.mesh_asset_id) else {
                 continue;
             };

crates/bevy_pbr/src/prepass/mod.rs

@@ -945,6 +945,10 @@ pub fn specialize_prepass_material_meshes<M>(
             let Ok(material_asset_id) = material_instance.asset_id.try_typed::<M>() else {
                 continue;
             };
+            let Some(mesh_instance) = render_mesh_instances.render_mesh_queue_data(*visible_entity)
+            else {
+                continue;
+            };
             let entity_tick = entity_specialization_ticks.get(visible_entity).unwrap();
             let last_specialized_tick = view_specialized_material_pipeline_cache
                 .get(visible_entity)
@@ -956,10 +960,6 @@ pub fn specialize_prepass_material_meshes<M>(
             if !needs_specialization {
                 continue;
             }
-            let Some(mesh_instance) = render_mesh_instances.render_mesh_queue_data(*visible_entity)
-            else {
-                continue;
-            };
             let Some(material) = render_materials.get(material_asset_id) else {
                 continue;
             };

crates/bevy_pbr/src/render/light.rs

@@ -1817,6 +1817,11 @@ pub fn specialize_shadows<M: Material>(
                 let Ok(material_asset_id) = material_instances.asset_id.try_typed::<M>() else {
                     continue;
                 };
+                let Some(mesh_instance) =
+                    render_mesh_instances.render_mesh_queue_data(visible_entity)
+                else {
+                    continue;
+                };
                 let entity_tick = entity_specialization_ticks.get(&visible_entity).unwrap();
                 let last_specialized_tick = view_specialized_material_pipeline_cache
                     .get(&visible_entity)
@@ -1831,11 +1836,6 @@ pub fn specialize_shadows<M: Material>(
                 let Some(material) = render_materials.get(material_asset_id) else {
                     continue;
                 };
-                let Some(mesh_instance) =
-                    render_mesh_instances.render_mesh_queue_data(visible_entity)
-                else {
-                    continue;
-                };
                 if !mesh_instance
                     .flags
                     .contains(RenderMeshInstanceFlags::SHADOW_CASTER)

crates/bevy_pbr/src/wireframe.rs

@@ -780,6 +780,10 @@ pub fn specialize_wireframes(
             if !render_wireframe_instances.contains_key(visible_entity) {
                 continue;
             };
+            let Some(mesh_instance) = render_mesh_instances.render_mesh_queue_data(*visible_entity)
+            else {
+                continue;
+            };
             let entity_tick = entity_specialization_ticks.get(visible_entity).unwrap();
             let last_specialized_tick = view_specialized_material_pipeline_cache
                 .get(visible_entity)
@@ -791,10 +795,6 @@ pub fn specialize_wireframes(
             if !needs_specialization {
                 continue;
             }
-            let Some(mesh_instance) = render_mesh_instances.render_mesh_queue_data(*visible_entity)
-            else {
-                continue;
-            };
             let Some(mesh) = render_meshes.get(mesh_instance.mesh_asset_id) else {
                 continue;
             };

crates/bevy_sprite/src/mesh2d/material.rs

@@ -722,6 +722,9 @@ pub fn specialize_material2d_meshes<M: Material2d>(
             let Some(material_asset_id) = render_material_instances.get(visible_entity) else {
                 continue;
             };
+            let Some(mesh_instance) = render_mesh_instances.get_mut(visible_entity) else {
+                continue;
+            };
             let entity_tick = entity_specialization_ticks.get(visible_entity).unwrap();
             let last_specialized_tick = view_specialized_material_pipeline_cache
                 .get(visible_entity)
@@ -733,9 +736,6 @@ pub fn specialize_material2d_meshes<M: Material2d>(
             if !needs_specialization {
                 continue;
             }
-            let Some(mesh_instance) = render_mesh_instances.get_mut(visible_entity) else {
-                continue;
-            };
             let Some(material_2d) = render_materials.get(*material_asset_id) else {
                 continue;
             };

crates/bevy_sprite/src/mesh2d/wireframe2d.rs

@@ -771,6 +771,9 @@ pub fn specialize_wireframes(
             if !render_wireframe_instances.contains_key(visible_entity) {
                 continue;
             };
+            let Some(mesh_instance) = render_mesh_instances.get(visible_entity) else {
+                continue;
+            };
             let entity_tick = entity_specialization_ticks.get(visible_entity).unwrap();
             let last_specialized_tick = view_specialized_material_pipeline_cache
                 .get(visible_entity)
@@ -782,9 +785,6 @@ pub fn specialize_wireframes(
             if !needs_specialization {
                 continue;
             }
-            let Some(mesh_instance) = render_mesh_instances.get(visible_entity) else {
-                continue;
-            };
             let Some(mesh) = render_meshes.get(mesh_instance.mesh_asset_id) else {
                 continue;
             };