Fix 1.8-1.15.2 bobbing

src/main/java/main/java/me/dniym/checks/BadAttributeCheck.java

@@ -1,6 +1,10 @@
 package main.java.me.dniym.checks;
 
+import com.google.common.collect.Multimap;
 import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
 import main.java.me.dniym.IllegalStack;
 import main.java.me.dniym.enums.Msg;
 import main.java.me.dniym.enums.Protections;
@@ -12,6 +16,7 @@ import org.bukkit.attribute.Attribute;
 import org.bukkit.attribute.AttributeModifier;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.CraftingInventory;
+import org.bukkit.inventory.EquipmentSlot;
 import org.bukkit.inventory.ItemFlag;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.ItemMeta;
@@ -53,51 +58,99 @@ public class BadAttributeCheck {
 
         }
 
-        return is != null && is.getType() != Material.AIR && checkForBadCustomData(is, obj);
+        return hasNonDefaultAttributeModifiers(is);
+
+    }
+
+    /**
+     * Pure predicate: true iff the item carries at least one AttributeModifier that
+     * is NOT part of the vanilla default modifier set for its Material. Vanilla
+     * defaults are exposed via ItemMeta on 1.20.5+, so a naive
+     * hasAttributeModifiers() check false-positives every vanilla weapon/armor and
+     * causes inventory churn when the periodic scanner rewrites the meta.
+     */
+    public static boolean hasNonDefaultAttributeModifiers(ItemStack is) {
+
+        if (is == null || is.getType() == Material.AIR) {
+
+            return false;
+
+        }
+
+        if (IllegalStack.isHasAttribAPI()) {
+
+            ItemMeta meta = is.getItemMeta();
+            return meta != null && hasCustomModifier(meta, is.getType());
+
+        }
+
+        if (IllegalStack.isNbtAPI()) {
+
+            return NBTApiStuff.hasBadCustomDataLegacy(is);
+
+        }
+
+        return false;
 
     }
 
     public static boolean checkForBadCustomData(ItemStack itemStack, Object obj) {
 
-        ItemMeta itemMeta = itemStack.getItemMeta();
         if (IllegalStack.isHasAttribAPI()) {
 
-            if (itemMeta.hasAttributeModifiers()) {
+            ItemMeta itemMeta = itemStack.getItemMeta();
+            if (itemMeta == null || !itemMeta.hasAttributeModifiers()) {
 
-                StringBuilder attribs = new StringBuilder();
-                HashSet<Attribute> toRemove = new HashSet<>();
-                for (Attribute a : itemMeta.getAttributeModifiers().keySet()) {
-
-                    for (AttributeModifier st : itemMeta.getAttributeModifiers(a)) {
-
-                        attribs.append(" ").append(st.getName()).append(" value: ").append(st.getAmount());
-
-                    }
-
-                    toRemove.add(a);
-
-                }
-
-                fListener.getLog().append(Msg.CustomAttribsRemoved3.getValue(itemStack, obj, attribs),
-                        Protections.RemoveCustomAttributes);
-
-                for (Attribute remove : toRemove) {
-
-                    itemMeta.removeAttributeModifier(remove);
-
-                }
-
-                for (ItemFlag iFlag : itemMeta.getItemFlags()) {
-
-                    itemMeta.removeItemFlags(iFlag);
-
-                }
-
-                itemStack.setItemMeta(itemMeta);
-                return true;
+                return false;
 
             }
 
+            Set<UUID> defaultUuids = collectDefaultModifierUuids(itemStack.getType());
+            Multimap<Attribute, AttributeModifier> mods = itemMeta.getAttributeModifiers();
+
+            StringBuilder attribs = new StringBuilder();
+            boolean anyCustom = false;
+            for (Map.Entry<Attribute, AttributeModifier> entry : mods.entries()) {
+
+                AttributeModifier mod = entry.getValue();
+                if (!defaultUuids.contains(mod.getUniqueId())) {
+
+                    anyCustom = true;
+                    attribs.append(" ").append(mod.getName()).append(" value: ").append(mod.getAmount());
+
+                }
+
+            }
+
+            if (!anyCustom) {
+
+                return false;
+
+            }
+
+            fListener.getLog().append(Msg.CustomAttribsRemoved3.getValue(itemStack, obj, attribs),
+                    Protections.RemoveCustomAttributes);
+
+            for (Map.Entry<Attribute, AttributeModifier> entry : mods.entries()) {
+
+                AttributeModifier mod = entry.getValue();
+                if (!defaultUuids.contains(mod.getUniqueId())) {
+
+                    itemMeta.removeAttributeModifier(entry.getKey(), mod);
+
+                }
+
+            }
+
+            for (ItemFlag iFlag : itemMeta.getItemFlags()) {
+
+                itemMeta.removeItemFlags(iFlag);
+
+            }
+
+            itemStack.setItemMeta(itemMeta);
+            return true;
+
         } else if (IllegalStack.isNbtAPI()) {
 
             return NBTApiStuff.checkForBadCustomDataLegacy(itemStack, obj);
@@ -113,4 +166,67 @@ public class BadAttributeCheck {
 
     }
 
+    private static boolean hasCustomModifier(ItemMeta meta, Material type) {
+
+        if (!meta.hasAttributeModifiers()) {
+
+            return false;
+
+        }
+
+        Set<UUID> defaultUuids = collectDefaultModifierUuids(type);
+        Multimap<Attribute, AttributeModifier> mods = meta.getAttributeModifiers();
+        for (AttributeModifier mod : mods.values()) {
+
+            if (!defaultUuids.contains(mod.getUniqueId())) {
+
+                return true;
+
+            }
+
+        }
+
+        return false;
+
+    }
+
+    public static Set<UUID> collectDefaultModifierUuidsPublic(Material type) {
+
+        return collectDefaultModifierUuids(type);
+
+    }
+
+    private static Set<UUID> collectDefaultModifierUuids(Material type) {
+
+        Set<UUID> uuids = new HashSet<>();
+        for (EquipmentSlot slot : EquipmentSlot.values()) {
+
+            try {
+
+                Multimap<Attribute, AttributeModifier> defaults = type.getDefaultAttributeModifiers(slot);
+                if (defaults == null) {
+
+                    continue;
+
+                }
+
+                for (AttributeModifier defMod : defaults.values()) {
+
+                    uuids.add(defMod.getUniqueId());
+
+                }
+
+            } catch (Throwable ignored) {
+
+                // Method may not exist on older servers, or the slot is incompatible
+                // with this material. Degrade gracefully: treat as no defaults known
+                // for that slot.
+            }
+
+        }
+
+        return uuids;
+
+    }
+
 }

src/main/java/main/java/me/dniym/utils/NBTStuff.java

@@ -1,6 +1,5 @@
 package main.java.me.dniym.utils;
 
-import java.util.HashSet;
 import main.java.me.dniym.IllegalStack;
 import main.java.me.dniym.enums.Msg;
 import main.java.me.dniym.enums.Protections;
@@ -216,19 +215,7 @@ public class NBTStuff {
 
     public static boolean hasBadCustomData(ItemStack is) {
 
-        ItemMeta im = is.getItemMeta();
-
-        if (IllegalStack.isHasAttribAPI() && is.hasItemMeta() && im.hasAttributeModifiers()) {
-
-            return true;
-
-        } else if (IllegalStack.isNbtAPI()) {
-
-            return NBTApiStuff.hasBadCustomDataLegacy(is);
-
-        }
-
-        return false;
+        return main.java.me.dniym.checks.BadAttributeCheck.hasNonDefaultAttributeModifiers(is);
 
     }
 
@@ -269,17 +256,27 @@ public class NBTStuff {
 
         if (IllegalStack.isHasAttribAPI() && im.hasAttributeModifiers()) {
 
+            java.util.Set<java.util.UUID> defaultUuids = main.java.me.dniym.checks.BadAttributeCheck
+                    .collectDefaultModifierUuidsPublic(is.getType());
+            com.google.common.collect.Multimap<Attribute, AttributeModifier> mods = im.getAttributeModifiers();
+
             StringBuilder attribs = new StringBuilder();
-            HashSet<Attribute> toRemove = new HashSet<>();
-            for (Attribute a : im.getAttributeModifiers().keySet()) {
+            boolean anyCustom = false;
+            for (java.util.Map.Entry<Attribute, AttributeModifier> entry : mods.entries()) {
 
-                for (AttributeModifier st : im.getAttributeModifiers(a)) {
+                AttributeModifier mod = entry.getValue();
+                if (!defaultUuids.contains(mod.getUniqueId())) {
 
-                    attribs.append(" ").append(st.getName()).append(" value: ").append(st.getAmount());
+                    anyCustom = true;
+                    attribs.append(" ").append(mod.getName()).append(" value: ").append(mod.getAmount());
 
                 }
 
-                toRemove.add(a);
+            }
+
+            if (!anyCustom) {
+
+                return;
 
             }
 
@@ -294,9 +291,14 @@ public class NBTStuff {
 
             }
 
-            for (Attribute remove : toRemove) {
+            for (java.util.Map.Entry<Attribute, AttributeModifier> entry : mods.entries()) {
 
-                im.removeAttributeModifier(remove);
+                AttributeModifier mod = entry.getValue();
+                if (!defaultUuids.contains(mod.getUniqueId())) {
+
+                    im.removeAttributeModifier(entry.getKey(), mod);
+
+                }
 
             }