From aa63051db3eef6f883dfdbe3e7c65ff4423dfd05 Mon Sep 17 00:00:00 2001
From: Ukendio <ukendio@gmail.com>
Date: Sun, 21 Dec 2025 19:21:42 +0100
Subject: [PATCH] Optimize idr_r removal by 35%

---
 src/jecs.luau   | 15 +++++++++++--
 test/tests.luau | 57 +++++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/src/jecs.luau b/src/jecs.luau
index 2045474..a3faf79 100755
--- a/src/jecs.luau
+++ b/src/jecs.luau
@@ -3246,22 +3246,33 @@ local function world_new()
 				local records = idr_r.records
 				for archetype_id in archetype_ids do
 					local idr_r_archetype = archetypes[archetype_id]
-					local node = idr_r_archetype
+					-- local node = idr_r_archetype
 					local entities = idr_r_archetype.entities
 					local tr = records[archetype_id]
 					local tr_count = counts[archetype_id]
 					local idr_r_types = idr_r_archetype.types
+					local dst = table.clone(idr_r_types)
 					for i = tr, tr + tr_count - 1 do
 						local id = idr_r_types[i]
-						node = archetype_traverse_remove(world, id, node)
+						local at = table.find(dst, id)
+						if at then
+							table.remove(dst, at)
+						end
+						-- node = archetype_traverse_remove(world, id, node)
 						local on_remove = component_index[id].on_remove
 						if on_remove then
+							-- NOTE(marcus): Since hooks can move the entities
+							-- assumptions about which archetype it jumps to is
+							-- diminished. We assume that people who delete
+							-- relation will never have hooks on them.
 							for _, entity in entities do
 								on_remove(entity, id)
 							end
 						end
 					end
 
+					local node = archetype_ensure(world, dst)
+
 					for i = #entities, 1, -1 do
 						local e = entities[i]
 						local r = entity_index_try_get_unsafe(e) :: record
diff --git a/test/tests.luau b/test/tests.luau
index b4d6c55..5133342 100755
--- a/test/tests.luau
+++ b/test/tests.luau
@@ -24,6 +24,59 @@ type Id<T=unknown> = jecs.Id<T>
 local entity_visualiser = require("@modules/entity_visualiser")
 local dwi = entity_visualiser.stringify
 
+TEST("optimize idr_r removal", function()
+
+	local pair = jecs.pair
+    local world = jecs.world()
+    local rel = world:component()
+    local A = world:component()
+    local B = world:component()
+
+    local t1 = world:entity()
+    local t2 = world:entity()
+
+    local entities = {} :: { jecs.Entity }
+
+    for i = 1, 10 do
+
+	    local e1 = world:entity()
+        local e2 = world:entity()
+
+        world:set(e1, A, true)
+        world:set(e2, A, true)
+        world:add(e1, pair(B, t1))
+        world:add(e1, pair(B, t2))
+        world:add(e2, pair(B, t1))
+        world:add(e2, pair(B, t2))
+
+        table.insert(entities, e1)
+        table.insert(entities, e2)
+    end
+
+    local e1 = world:entity()
+    local e2 = world:entity()
+
+    table.insert(entities, e1)
+	table.insert(entities, e2)
+
+    world:set(e1, A, true)
+    world:set(e2, A, true)
+    world:add(e1, pair(B, t1))
+    world:add(e1, pair(B, t2))
+    world:add(e2, pair(B, t1))
+    world:add(e2, pair(B, t2))
+
+    BENCH("delete B", function()
+    	world:delete(B)
+    end)
+
+    for _, e in entities do
+	    CHECK(world:has(e, A))
+        CHECK(not world:target(e, B))
+        CHECK(not world:target(e, B))
+    end
+
+end)
 TEST("deleting t1's archetype before invoking its onremove hooks", function()
     local pair = jecs.pair
     local world = jecs.world()
@@ -96,10 +149,6 @@ TEST("reproduce idr_t nil archetype bug", function()
 	        -- Removing this, but keeping Animator on the other 2 causes it to stop happening
 	        world:set(trackEntity1, cts.VelocitizeAnimationWeight, 0)
 
-									print("delete root")
-	        world:delete(root)
-									print("---")
-
 	        for entityId, info in trackedEntities do
 	            if world:contains(entityId) and not world:parent(entityId :: any) then
 	                print(`bugged entity found: {entityId}`)