Fix use_item packet format for Minecraft 1.21+ compatibility

lib/plugins/inventory.js

@@ -125,11 +125,22 @@ function inject (bot, { hideErrors }) {
         cursorZ: -1
       })
     } else if (bot.supportFeature('useItemWithOwnPacket')) {
-      bot._client.write('use_item', {
+      const packet = {
         hand: offHand ? 1 : 0,
-        sequence,
-        rotation: { x: 0, y: 0 }
-      })
+        sequence
+      }
+
+      // In 1.21+, use_item packet format changed from rotation vec2f to separate yaw/pitch floats
+      // TODO: Replace with proper feature flag once added to minecraft-data
+      if (bot.supportFeature('useItemHasSeparateYawPitch') ||
+          (bot.version && bot.version.split('.').map(Number)[1] >= 21)) {
+        packet.yaw = 0
+        packet.pitch = 0
+      } else {
+        packet.rotation = { x: 0, y: 0 }
+      }
+
+      bot._client.write('use_item', packet)
     }
   }
 

lib/plugins/place_entity.js

@@ -36,9 +36,22 @@ function inject (bot) {
 
     if (type === 'boat') {
       if (bot.supportFeature('useItemWithOwnPacket')) {
-        bot._client.write('use_item', {
-          hand: options.offhand ? 1 : 0
-        })
+        const packet = {
+          hand: options.offhand ? 1 : 0,
+          sequence: 0
+        }
+
+        // In 1.21+, use_item packet format changed from rotation vec2f to separate yaw/pitch floats
+        // TODO: Replace with proper feature flag once added to minecraft-data
+        if (bot.supportFeature('useItemHasSeparateYawPitch') ||
+            (bot.version && bot.version.split('.').map(Number)[1] >= 21)) {
+          packet.yaw = 0
+          packet.pitch = 0
+        } else {
+          packet.rotation = { x: 0, y: 0 }
+        }
+
+        bot._client.write('use_item', packet)
       } else {
         bot._client.write('block_place', {
           location: { x: -1, y: -1, z: -1 },

test/externalTests/activateItem.js

@@ -0,0 +1,42 @@
+const assert = require('assert')
+
+module.exports = () => async (bot) => {
+  // Test that activateItem works and has observable effects on the world
+  // This reproduces the issue where activateItem fails on 1.21+ due to packet format changes
+
+  const Item = require('prismarine-item')(bot.registry)
+
+  // Set up conditions for testing item activation
+  await bot.test.setInventorySlot(36, new Item(bot.registry.itemsByName.bread.id, 5, 0))
+  await bot.test.becomeSurvival()
+
+  // Reduce food level so bread can be consumed
+  while (bot.food > 10) {
+    if (bot.supportFeature('effectAreNotPrefixed')) bot.test.sayEverywhere('/effect give @s hunger 1 255')
+    else if (bot.supportFeature('effectAreMinecraftPrefixed')) bot.test.sayEverywhere(`/effect ${bot.username} minecraft:hunger 1 255`)
+    await bot.test.wait(500)
+  }
+
+  const initialFood = bot.food
+  const initialItemCount = bot.heldItem.count
+
+  // Test that activateItem works and has observable server-side effects
+  assert.ok(!bot.usingHeldItem, 'Should not be using item initially')
+
+  // Use activateItem instead of consume to test the packet format
+  bot.activateItem()
+  assert.ok(bot.usingHeldItem, 'Should be using item after activateItem')
+
+  // Wait for the server to process the action and observe effects
+  await bot.test.wait(2000)
+
+  // Verify the server processed the item use by checking observable changes
+  const finalFood = bot.food
+  const finalItemCount = bot.heldItem ? bot.heldItem.count : 0
+
+  // The server should have processed the bread consumption
+  assert.ok(finalFood > initialFood || finalItemCount < initialItemCount,
+    'Server should have processed item activation (food increased or item consumed)')
+
+  assert.ok(!bot.usingHeldItem, 'Should not be using item after server processes it')
+}