More Chest Block API

== AT ==
public net.minecraft.world.level.block.ChestBlock isBlockedChestByBlock(Lnet/minecraft/world/level/BlockGetter;Lnet/minecraft/core/BlockPos;)Z

paper-server/patches/sources/net/minecraft/world/level/block/EnderChestBlock.java.patch

@@ -0,0 +1,11 @@
+--- a/net/minecraft/world/level/block/EnderChestBlock.java
++++ b/net/minecraft/world/level/block/EnderChestBlock.java
+@@ -78,7 +78,7 @@
+         PlayerEnderChestContainer playerEnderChestContainer = player.getEnderChestInventory();
+         if (playerEnderChestContainer != null && world.getBlockEntity(pos) instanceof EnderChestBlockEntity enderChestBlockEntity) {
+             BlockPos blockPos = pos.above();
+-            if (world.getBlockState(blockPos).isRedstoneConductor(world, blockPos)) {
++            if (world.getBlockState(blockPos).isRedstoneConductor(world, blockPos)) { // Paper - diff on change; make sure that EnderChest#isBlocked uses the same logic
+                 return InteractionResult.SUCCESS;
+             } else {
+                 if (world instanceof ServerLevel serverLevel) {

paper-server/src/main/java/org/bukkit/craftbukkit/block/CraftChest.java

@@ -99,4 +99,29 @@ public class CraftChest extends CraftLootable<ChestBlockEntity> implements Chest
         return getTileEntity().openersCounter.opened;
     }
     // Paper end - More Lidded Block API
+
+    // Paper start - More Chest Block API
+    @Override
+    public boolean isBlocked() {
+        // Method mimics vanilla logic in ChestBlock and DoubleBlockCombiner when trying to open chest's container
+        if (!isPlaced()) {
+            return false;
+        }
+        net.minecraft.world.level.LevelAccessor world = getWorldHandle();
+        if (ChestBlock.isChestBlockedAt(world, getPosition())) {
+            return true;
+        }
+        if (ChestBlock.getBlockType(this.data) == net.minecraft.world.level.block.DoubleBlockCombiner.BlockType.SINGLE) {
+            return false;
+        }
+        net.minecraft.core.Direction direction = ChestBlock.getConnectedDirection(this.data);
+        net.minecraft.core.BlockPos neighbourBlockPos = getPosition().relative(direction);
+        BlockState neighbourBlockState = world.getBlockStateIfLoaded(neighbourBlockPos);
+        return neighbourBlockState != null
+            && neighbourBlockState.is(this.data.getBlock())
+            && ChestBlock.getBlockType(neighbourBlockState) != net.minecraft.world.level.block.DoubleBlockCombiner.BlockType.SINGLE
+            && ChestBlock.getConnectedDirection(neighbourBlockState) == direction.getOpposite()
+            && ChestBlock.isChestBlockedAt(world, neighbourBlockPos);
+    }
+    // Paper end - More Chest Block API
 }

paper-server/src/main/java/org/bukkit/craftbukkit/block/CraftEnderChest.java

@@ -58,4 +58,13 @@ public class CraftEnderChest extends CraftBlockEntityState<EnderChestBlockEntity
         return getTileEntity().openersCounter.opened;
     }
     // Paper end - More Lidded Block API
+
+    // Paper start - More Chest Block API
+    @Override
+    public boolean isBlocked() {
+        // Uses the same logic as EnderChestBlock's check for opening container
+        final net.minecraft.core.BlockPos abovePos = this.getPosition().above();
+        return this.isPlaced() && this.getWorldHandle().getBlockState(abovePos).isRedstoneConductor(this.getWorldHandle(), abovePos);
+    }
+    // Paper end - More Chest Block API
 }