accurately track when the player's screen handler changes

Author: beanbag44

src/main/java/com/lambda/mixin/entity/HandledScreensMixin.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2025 Lambda
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lambda.mixin.entity;
+
+import com.lambda.interaction.request.inventory.InventoryManager;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.gui.screen.ingame.HandledScreens;
+import net.minecraft.screen.ScreenHandler;
+import net.minecraft.screen.ScreenHandlerType;
+import net.minecraft.text.Text;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(HandledScreens.Provider.class)
+public interface HandledScreensMixin {
+    @Inject(method = "open", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/MinecraftClient;setScreen(Lnet/minecraft/client/gui/screen/Screen;)V"))
+    private void injectOpen(Text name, ScreenHandlerType<ScreenHandler> type, MinecraftClient client, int id, CallbackInfo ci) {
+        if (client.player == null) return;
+        InventoryManager.onSetScreenHandler(client.player.currentScreenHandler);
+    }
+}

src/main/kotlin/com/lambda/interaction/request/inventory/InventoryManager.kt

@@ -17,10 +17,11 @@
 
 package com.lambda.interaction.request.inventory
 
-import com.lambda.context.AutomatedSafeContext
 import com.lambda.config.AutomationConfig.Companion.DEFAULT
+import com.lambda.context.AutomatedSafeContext
 import com.lambda.context.SafeContext
 import com.lambda.event.EventFlow.post
+import com.lambda.event.events.PacketEvent
 import com.lambda.event.events.TickEvent
 import com.lambda.event.events.UpdateManagerEvent
 import com.lambda.event.listener.SafeListener.Companion.listen
@@ -38,6 +39,7 @@ import com.lambda.util.item.ItemStackUtils.equal
 import com.llamalad7.mixinextras.injector.wrapoperation.Operation
 import net.minecraft.client.gui.screen.ingame.CreativeInventoryScreen
 import net.minecraft.item.ItemStack
+import net.minecraft.network.packet.c2s.play.CloseHandledScreenC2SPacket
 import net.minecraft.network.packet.s2c.play.InventoryS2CPacket
 import net.minecraft.network.packet.s2c.play.ScreenHandlerSlotUpdateS2CPacket
 import net.minecraft.screen.PlayerScreenHandler
@@ -60,14 +62,16 @@ object InventoryManager : RequestHandler<InventoryRequest>(
     private var actions = mutableListOf<InventoryAction>()
 
     private var slots = listOf<ItemStack>()
-    private var alteredSlots = LimitedDecayQueue<Pair<Int, Pair<ItemStack, ItemStack>>>(
+    private var alteredSlots = LimitedDecayQueue<InventoryChange>(
         Int.MAX_VALUE, DEFAULT.desyncTimeout * 50L
     )
 
     private var screenHandler: ScreenHandler? = null
         set(value) {
-            if (value != null && field?.syncId != value.syncId)
+            if (value != null && field?.syncId != value.syncId) {
+                alteredSlots.clear()
                 slots = getStacks(value.slots)
+            }
             field = value
         }
 
@@ -92,6 +96,14 @@ object InventoryManager : RequestHandler<InventoryRequest>(
             actions = mutableListOf()
         }
 
+        listen<PacketEvent.Send.Pre> { event ->
+            if (event.packet is CloseHandledScreenC2SPacket &&
+                event.packet.syncId != player.currentScreenHandler.syncId
+                ) {
+                screenHandler = player.playerScreenHandler
+            }
+        }
+
         return "Loaded Inventory Manager"
     }
 
@@ -136,7 +148,6 @@ object InventoryManager : RequestHandler<InventoryRequest>(
         activeRequest?.let { active ->
             PlaceManager.logger.debug("Processing request", active)
             if (tickStage !in active.inventoryConfig.tickStageMask && active.nowOrNothing) return
-            screenHandler = player.currentScreenHandler
             val iterator = actions.iterator()
             while (iterator.hasNext()) {
                 val action = iterator.next()
@@ -169,7 +180,7 @@ object InventoryManager : RequestHandler<InventoryRequest>(
         if (player.currentScreenHandler.syncId != screenHandler?.syncId) return
         val changes = screenHandler?.slots
             ?.filter { !it.stack.equal(slots[it.id]) }
-            ?.map { Pair(it.id, Pair(slots[it.id], it.stack.copy())) }
+            ?.map { InventoryChange(it.id, slots[it.id], it.stack.copy()) }
             ?: emptyList()
         alteredSlots.addAll(changes)
         slots = getStacks(player.currentScreenHandler.slots)
@@ -189,7 +200,6 @@ object InventoryManager : RequestHandler<InventoryRequest>(
                 original.call(packet)
                 return
             }
-            screenHandler = player.currentScreenHandler
             val packetScreenHandler =
                 when (packet.syncId) {
                     0 -> player.playerScreenHandler
@@ -199,7 +209,7 @@ object InventoryManager : RequestHandler<InventoryRequest>(
             val alteredContents = mutableListOf<ItemStack>()
             packet.contents.forEachIndexed { index, incomingStack ->
                 val matches = alteredSlots.removeIf { cached ->
-                    incomingStack.equal(cached.second.second)
+                    incomingStack.equal(cached.after)
                 }
                 if (matches) alteredContents.add(packetScreenHandler.slots[index].stack)
                 else alteredContents.add(incomingStack)
@@ -218,7 +228,6 @@ object InventoryManager : RequestHandler<InventoryRequest>(
     @JvmStatic
     fun onSlotUpdate(packet: ScreenHandlerSlotUpdateS2CPacket, original: Operation<Void>) {
         runSafe {
-            screenHandler = player.currentScreenHandler
             if (!mc.isOnThread || !DEFAULT.avoidDesync) {
                 original.call(packet)
                 return
@@ -231,7 +240,7 @@ object InventoryManager : RequestHandler<InventoryRequest>(
             } ?: false
 
             val matches = alteredSlots.removeIf {
-                it.first == packet.slot && it.second.second.equal(itemStack)
+                it.syncId == packet.slot && it.after.equal(itemStack)
             }
 
             if (packet.syncId == 0) {
@@ -255,5 +264,16 @@ object InventoryManager : RequestHandler<InventoryRequest>(
         original.call(packet)
     }
 
+    @JvmStatic
+    fun onSetScreenHandler(screenHandler: ScreenHandler) {
+        this.screenHandler = screenHandler
+    }
+
+    private data class InventoryChange(
+        val syncId: Int,
+        val before: ItemStack,
+        val after: ItemStack
+    )
+
     override fun preEvent() = UpdateManagerEvent.Inventory.post()
 }

src/main/resources/lambda.mixins.common.json

@@ -13,6 +13,7 @@
     "entity.ClientPlayInteractionManagerMixin",
     "entity.EntityMixin",
     "entity.FireworkRocketEntityMixin",
+    "entity.HandledScreensMixin",
     "entity.LivingEntityMixin",
     "entity.PlayerEntityMixin",
     "entity.PlayerInventoryMixin",