Make world:set idempotent for tags

CHANGELOG.md

@@ -9,6 +9,9 @@ The format is based on [Keep a Changelog][kac], and this project adheres to
 [semver]: https://semver.org/spec/v2.0.0.html
 
 ## [Unreleased]
+- `[world]`:
+    - Improved performance for hooks
+    - Changed `world:set` to be idempotent when setting tags
 - `[traits]`:
     - Added cleanup condition `jecs.OnDelete` for when the entity or component is deleted
     - Added cleanup action `jecs.Remove` which removes instances of the specified (component) id from all entities

src/init.luau

@@ -630,7 +630,7 @@ local function world_set(world: World, entity: i53, id: i53, data: unknown)
 	local idr = world.componentIndex[id]
 	local flags = idr.flags
 	local is_tag = bit32.band(flags, ECS_ID_IS_TAG) ~= 0
-	local has_on_set = bit32.band(idr.flags, ECS_ID_HAS_ON_SET) ~= 0
+	local has_on_set = bit32.band(flags, ECS_ID_HAS_ON_SET) ~= 0
 
 	if from == to then
 		if is_tag then
@@ -657,17 +657,22 @@ local function world_set(world: World, entity: i53, id: i53, data: unknown)
 		end
 	end
 
-	local tr = to.records[id]
-	local column = to.columns[tr.column]
+	local has_on_add = bit32.band(flags, ECS_ID_HAS_ON_ADD) ~= 0
+
+	if has_on_add then
+	    invoke_hook(world, EcsOnAdd, id, entity)
+	end
 
 	if is_tag then
 		return
 	end
-	if not has_on_set then
-		column[record.row] = data
-	else
-		invoke_hook(world, EcsOnAdd, id, entity, data)
+
+	local tr = to.records[id]
+	local column = to.columns[tr.column]
+
 	column[record.row] = data
+
+	if has_on_set then
 	    invoke_hook(world, EcsOnSet, id, entity, data)
 	end
 end