Fix banner crashing client when copying blank vanilia banner and desync in multiplayer

src/main/java/com/minecolonies/core/client/render/TileEntityColonyFlagRenderer.java

@@ -53,7 +53,7 @@ public TileEntityColonyFlagRenderer(final BlockEntityRendererProvider.Context co
     @Override
     public void render(TileEntityColonyFlag flagIn, float partialTicks, PoseStack transform, MultiBufferSource bufferIn, int combinedLightIn, int combinedOverlayIn)
     {
-        List<Pair<Holder<BannerPattern>, DyeColor>> list = flagIn.getPatternList();
+        List<Pair<Holder<BannerPattern>, DyeColor>> list = flagIn.getPatterns();
 
         boolean noWorld = flagIn.getLevel() == null;
         transform.pushPose();

src/main/java/com/minecolonies/core/items/ItemColonyFlagBanner.java

@@ -2,17 +2,19 @@
 
 import com.minecolonies.api.blocks.ModBlocks;
 import com.minecolonies.core.tileentities.TileEntityColonyFlag;
-import net.minecraft.world.level.block.AbstractBannerBlock;
+import com.mojang.datafixers.util.Pair;
+
 import net.minecraft.world.level.block.Block;
-import net.minecraft.world.level.block.entity.BannerPatterns;
-import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.item.TooltipFlag;
 import net.minecraft.world.item.BannerItem;
+import net.minecraft.world.item.BlockItem;
+import net.minecraft.world.item.DyeColor;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.context.UseOnContext;
+import net.minecraft.core.Holder;
 import net.minecraft.nbt.CompoundTag;
-import net.minecraft.nbt.ListTag;
 import net.minecraft.world.level.block.entity.BannerBlockEntity;
+import net.minecraft.world.level.block.entity.BannerPattern;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.InteractionResult;
 import net.minecraft.network.chat.Component;
@@ -46,38 +48,27 @@ public InteractionResult useOn(UseOnContext context)
     {
         // Duplicate the patterns of the banner that was clicked on
         BlockEntity te = context.getLevel().getBlockEntity(context.getClickedPos());
-        BlockState state = context.getLevel().getBlockState(context.getClickedPos());
-        ItemStack stack = context.getPlayer().getMainHandItem();
+        ItemStack stack = context.getItemInHand();
 
         if (te instanceof BannerBlockEntity || te instanceof TileEntityColonyFlag)
         {
-            CompoundTag source;
+            BannerPattern.Builder patternsBuilder = new BannerPattern.Builder();
+            List<Pair<Holder<BannerPattern>, DyeColor>> source;
+
             if (te instanceof BannerBlockEntity)
             {
-                source = ((BannerBlockEntity) te).getItem()
-                           .getTag().getCompound("BlockEntityTag");
+                source = ((BannerBlockEntity) te).getPatterns();
             }
             else
             {
-                source = (context.getLevel().isClientSide ? ((TileEntityColonyFlag) te).getItemClient() : ((TileEntityColonyFlag) te).getItemServer())
-                           .getTag().getCompound("BlockEntityTag");
-            }
-
-            ListTag patternList = source.getList(TAG_BANNER_PATTERNS, 10);
-
-            // Set the base pattern, if there wasn't one set.
-            // This saves us attempting to alter the item itself to change the base color.
-            if (!patternList.getCompound(0).getString(TAG_SINGLE_PATTERN).equals(BannerPatterns.BASE.location().toString()))
-            {
-                CompoundTag nbt = new CompoundTag();
-                nbt.putString(TAG_SINGLE_PATTERN, BannerPatterns.BASE.location().toString());
-                nbt.putInt(TAG_PATTERN_COLOR, ((AbstractBannerBlock) state.getBlock()).getColor().getId());
-                patternList.add(0, nbt);
+                source = ((TileEntityColonyFlag) te).getPatterns();
             }
 
-            CompoundTag tag = stack.getOrCreateTagElement("BlockEntityTag");
-            tag.put(TAG_BANNER_PATTERNS, patternList);
+            CompoundTag bannerPattern = new CompoundTag();
+            source.forEach((pattern) -> patternsBuilder.addPattern(pattern.getFirst(), pattern.getSecond()));
+            bannerPattern.put(TAG_BANNER_PATTERNS, patternsBuilder.toListTag());
 
+            stack.addTagElement("BlockEntityTag", bannerPattern);
             return InteractionResult.SUCCESS;
         }
         return super.useOn(context);
@@ -86,9 +77,14 @@ public InteractionResult useOn(UseOnContext context)
     @Override
     public void appendHoverText(ItemStack stack, @Nullable Level worldIn, List<Component> tooltip, TooltipFlag flagIn)
     {
-        super.appendHoverText(stack, worldIn, tooltip, flagIn);
-
-        // Remove the base, as they have no translations (Mojang were lazy. Or maybe saving space?)
-        if (tooltip.size() > 1) tooltip.remove(1);
+        CompoundTag tag = BlockItem.getBlockEntityData(stack);
+        if (tag != null && tag.contains(TAG_BANNER_PATTERNS))
+        {
+            super.appendHoverText(stack, worldIn, tooltip, flagIn);
+        }
+        else
+        {
+            tooltip.add(Component.translatable("com.minecolonies.coremod.item.colony_banner.tooltipempty"));
+        }
     }
 }

src/main/java/com/minecolonies/core/tileentities/TileEntityColonyFlag.java

@@ -28,9 +28,6 @@
 
 public class TileEntityColonyFlag extends BlockEntity
 {
-    /** The last known flag. Required for when the colony is not available. */
-    private ListTag flag = new ListTag();
-
     /** A list of the default banner patterns, for colonies that have not chosen a flag */
     private ListTag patterns = new ListTag();
 
@@ -44,7 +41,6 @@ public void saveAdditional(CompoundTag compound)
     {
         super.saveAdditional(compound);
 
-        compound.put(TAG_FLAG_PATTERNS, this.flag);
         compound.put(TAG_BANNER_PATTERNS, this.patterns);
 
         compound.putInt(TAG_COLONY_ID, colonyId);
@@ -55,7 +51,6 @@ public void load(CompoundTag compound)
     {
         super.load(compound);
 
-        this.flag = compound.getList(TAG_FLAG_PATTERNS, 10);
         this.patterns = compound.getList(TAG_BANNER_PATTERNS, 10);
         this.colonyId = compound.getInt(TAG_COLONY_ID);
 
@@ -87,27 +82,29 @@ public void onDataPacket(final Connection net, final ClientboundBlockEntityDataP
     }
 
     /**
-     * Retrieves the patterns for the renderer
+     * Retrieves the patterns, similar to {@link BannerBlockEntity#getPatterns()}
      * @return the list of pattern-color pairs
      */
-    @OnlyIn(Dist.CLIENT)
-    public List<Pair<Holder<BannerPattern>, DyeColor>> getPatternList()
+    public List<Pair<Holder<BannerPattern>, DyeColor>> getPatterns()
     {
         // Structurize will cause the second condition to be false
         if (level != null && level.dimension() != null)
         {
             IColonyView colony = IColonyManager.getInstance().getColonyView(this.colonyId, level.dimension());
-            if (colony != null && this.flag != colony.getColonyFlag())
+            if (colony != null && this.patterns != colony.getColonyFlag())
             {
-                this.flag = colony.getColonyFlag();
+                this.patterns = colony.getColonyFlag();
                 setChanged();
             }
         }
 
-        return BannerBlockEntity.createPatterns(
+        List<Pair<Holder<BannerPattern>, DyeColor>> pattern = BannerBlockEntity.createPatterns(
                 DyeColor.WHITE,
-                this.flag.size() > 1 ? this.flag : this.patterns
+                this.patterns
         );
+	//remove the first base layer
+	pattern.remove(0);
+    	return pattern;
     }
 
     /**
@@ -118,7 +115,7 @@ public List<Pair<Holder<BannerPattern>, DyeColor>> getPatternList()
     public ItemStack getItemClient()
     {
         ItemStack itemstack = new ItemStack(ModBlocks.blockColonyBanner);
-        List<Pair<Holder<BannerPattern>, DyeColor>> list = getPatternList();
+        List<Pair<Holder<BannerPattern>, DyeColor>> list = getPatterns();
         ListTag nbt = new ListTag();
 
         for (Pair<Holder<BannerPattern>, DyeColor> pair : list)

src/main/resources/assets/minecolonies/lang/manual_en_us.json

@@ -1921,6 +1921,7 @@
   "com.minecolonies.coremod.gui.flag.base_layer": "Base",
   "com.minecolonies.coremod.gui.townhall.edit_flag": "Edit Colony Flag",
   "block.minecolonies.colony_banner": "Colony Flag Banner",
+  "com.minecolonies.coremod.item.colony_banner.tooltipempty": "Right click to copy pattern on the item",
   "com.minecolonies.coremod.gui.locate": "Locate",
   "com.minecolonies.coremod.locating": "Successfully located rack with respective item(s).",