Fixed crash when placing many connectable blocks

(iron bars, glass panes, redstone)

The reason for this crash is that I precomputed the blockstates to be placed (which would be free standing poles when no blocks are present around them).
Placing all blocks at once then causes lots of block updates which may crash the game (especially in MC1.15).
So the solution is to calculate the blockstate directly before the placement.

src/main/java/thetadev/constructionwand/basics/WandUtil.java

@@ -235,54 +235,6 @@ public static boolean entitiesCollidingWithBlock(World world, BlockState blockSt
         return false;
     }
 
-    /**
-     * Tests if a certain block can be placed by the wand.
-     * If it can, returns the blockstate to be placed.
-     */
-    @SuppressWarnings({"rawtypes", "unchecked"})
-    @Nullable
-    public static BlockState getPlaceBlockstate(World world, PlayerEntity player, BlockRayTraceResult rayTraceResult,
-                                                BlockPos pos, BlockItem item,
-                                                @Nullable BlockState supportingBlock, @Nullable WandOptions options) {
-        // Is block at pos replaceable?
-        BlockItemUseContext ctx = new WandItemUseContext(world, player, rayTraceResult, pos, item);
-        if(!ctx.canPlace()) return null;
-
-        // Can block be placed?
-        BlockState blockState = item.getBlock().getStateForPlacement(ctx);
-        if(blockState == null) return null;
-
-        // Forbidden Tile Entity?
-        if(!isTEAllowed(blockState)) return null;
-
-        // No entities colliding?
-        if(entitiesCollidingWithBlock(world, blockState, pos)) return null;
-
-        // Adjust blockstate to neighbors
-        blockState = Block.getValidBlockForPosition(blockState, world, pos);
-        if(blockState.getBlock() == Blocks.AIR || !blockState.isValidPosition(world, pos)) return null;
-
-        // Copy block properties from supporting block
-        if(options != null && supportingBlock != null && options.direction.get() == WandOptions.DIRECTION.TARGET) {
-            // Block properties to be copied (alignment/rotation properties)
-
-            for(Property property : new Property[]{
-                    BlockStateProperties.HORIZONTAL_FACING, BlockStateProperties.FACING, BlockStateProperties.FACING_EXCEPT_UP,
-                    BlockStateProperties.ROTATION_0_15, BlockStateProperties.AXIS, BlockStateProperties.HALF, BlockStateProperties.STAIRS_SHAPE}) {
-                if(supportingBlock.hasProperty(property) && blockState.hasProperty(property)) {
-                    blockState = blockState.with(property, supportingBlock.get(property));
-                }
-            }
-
-            // Dont dupe double slabs
-            if(supportingBlock.hasProperty(BlockStateProperties.SLAB_TYPE) && blockState.hasProperty(BlockStateProperties.SLAB_TYPE)) {
-                SlabType slabType = supportingBlock.get(BlockStateProperties.SLAB_TYPE);
-                if(slabType != SlabType.DOUBLE) blockState = blockState.with(BlockStateProperties.SLAB_TYPE, slabType);
-            }
-        }
-        return blockState;
-    }
-
     public static Direction fromVector(Vector3d vector) {
         return Direction.getFacingFromVector(vector.x, vector.y, vector.z);
     }

src/main/java/thetadev/constructionwand/wand/WandJob.java

@@ -92,7 +92,7 @@ public boolean doIt() {
         for(ISnapshot snapshot : placeSnapshots) {
             if(wand.isEmpty() || wandItem.remainingDurability(wand) == 0) break;
 
-            if(snapshot.execute(world, player)) {
+            if(snapshot.execute(world, player, rayTraceResult)) {
                 // If the item cant be taken, undo the placement
                 if(wandSupplier.takeItemStack(snapshot.getRequiredItems()) == 0) executed.add(snapshot);
                 else {

src/main/java/thetadev/constructionwand/wand/undo/DestroySnapshot.java

@@ -5,15 +5,16 @@
 import net.minecraft.fluid.Fluids;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.BlockRayTraceResult;
 import net.minecraft.world.World;
 import thetadev.constructionwand.basics.WandUtil;
 
 import javax.annotation.Nullable;
 
 public class DestroySnapshot implements ISnapshot
 {
-    public final BlockState block;
-    public final BlockPos pos;
+    private final BlockState block;
+    private final BlockPos pos;
 
     public DestroySnapshot(BlockState block, BlockPos pos) {
         this.pos = pos;
@@ -43,7 +44,7 @@ public ItemStack getRequiredItems() {
     }
 
     @Override
-    public boolean execute(World world, PlayerEntity player) {
+    public boolean execute(World world, PlayerEntity player, BlockRayTraceResult rayTraceResult) {
         return WandUtil.removeBlock(world, player, block, pos);
     }
 

src/main/java/thetadev/constructionwand/wand/undo/ISnapshot.java

@@ -4,6 +4,7 @@
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.BlockRayTraceResult;
 import net.minecraft.world.World;
 
 public interface ISnapshot
@@ -14,7 +15,7 @@ public interface ISnapshot
 
     ItemStack getRequiredItems();
 
-    boolean execute(World world, PlayerEntity player);
+    boolean execute(World world, PlayerEntity player, BlockRayTraceResult rayTraceResult);
 
     boolean canRestore(World world, PlayerEntity player);
 

src/main/java/thetadev/constructionwand/wand/undo/PlaceSnapshot.java

@@ -1,36 +1,48 @@
 package thetadev.constructionwand.wand.undo;
 
+import net.minecraft.block.Block;
 import net.minecraft.block.BlockState;
+import net.minecraft.block.Blocks;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.BlockItem;
+import net.minecraft.item.BlockItemUseContext;
 import net.minecraft.item.ItemStack;
+import net.minecraft.state.Property;
+import net.minecraft.state.properties.BlockStateProperties;
+import net.minecraft.state.properties.SlabType;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockRayTraceResult;
 import net.minecraft.world.World;
 import thetadev.constructionwand.basics.WandUtil;
 import thetadev.constructionwand.basics.option.WandOptions;
+import thetadev.constructionwand.wand.WandItemUseContext;
 
 import javax.annotation.Nullable;
 
 public class PlaceSnapshot implements ISnapshot
 {
-    public final BlockState block;
-    public final BlockPos pos;
-    public final BlockItem item;
+    private BlockState block;
+    private final BlockPos pos;
+    private final BlockItem item;
+    private final BlockState supportingBlock;
+    private final boolean targetMode;
 
-    public PlaceSnapshot(BlockState block, BlockPos pos, BlockItem item) {
+    public PlaceSnapshot(BlockState block, BlockPos pos, BlockItem item, BlockState supportingBlock, boolean targetMode) {
         this.block = block;
         this.pos = pos;
         this.item = item;
+        this.supportingBlock = supportingBlock;
+        this.targetMode = targetMode;
     }
 
-    @Nullable
     public static PlaceSnapshot get(World world, PlayerEntity player, BlockRayTraceResult rayTraceResult,
                                     BlockPos pos, BlockItem item,
                                     @Nullable BlockState supportingBlock, @Nullable WandOptions options) {
-        BlockState blockState = WandUtil.getPlaceBlockstate(world, player, rayTraceResult, pos, item, supportingBlock, options);
+        boolean targetMode = options != null && supportingBlock != null && options.direction.get() == WandOptions.DIRECTION.TARGET;
+        BlockState blockState = getPlaceBlockstate(world, player, rayTraceResult, pos, item, supportingBlock, targetMode);
         if(blockState == null) return null;
-        return new PlaceSnapshot(blockState, pos, item);
+
+        return new PlaceSnapshot(blockState, pos, item, supportingBlock, targetMode);
     }
 
     @Override
@@ -49,7 +61,12 @@ public ItemStack getRequiredItems() {
     }
 
     @Override
-    public boolean execute(World world, PlayerEntity player) {
+    public boolean execute(World world, PlayerEntity player, BlockRayTraceResult rayTraceResult) {
+        // Recalculate PlaceBlockState, because other blocks might be placed nearby
+        // Not doing this may cause game crashes (StackOverflowException) when placing lots of blocks
+        // with changing orientation like panes, iron bars or redstone.
+        block = getPlaceBlockstate(world, player, rayTraceResult, pos, item, supportingBlock, targetMode);
+        if(block == null) return false;
         return WandUtil.placeBlock(world, player, block, pos, item);
     }
 
@@ -67,4 +84,52 @@ public boolean restore(World world, PlayerEntity player) {
     public void forceRestore(World world) {
         world.removeBlock(pos, false);
     }
+
+    /**
+     * Tests if a certain block can be placed by the wand.
+     * If it can, returns the blockstate to be placed.
+     */
+    @SuppressWarnings({"rawtypes", "unchecked"})
+    @Nullable
+    private static BlockState getPlaceBlockstate(World world, PlayerEntity player, BlockRayTraceResult rayTraceResult,
+                                                BlockPos pos, BlockItem item,
+                                                @Nullable BlockState supportingBlock, boolean targetMode) {
+        // Is block at pos replaceable?
+        BlockItemUseContext ctx = new WandItemUseContext(world, player, rayTraceResult, pos, item);
+        if(!ctx.canPlace()) return null;
+
+        // Can block be placed?
+        BlockState blockState = item.getBlock().getStateForPlacement(ctx);
+        if(blockState == null) return null;
+
+        // Forbidden Tile Entity?
+        if(!WandUtil.isTEAllowed(blockState)) return null;
+
+        // No entities colliding?
+        if(WandUtil.entitiesCollidingWithBlock(world, blockState, pos)) return null;
+
+        // Adjust blockstate to neighbors
+        blockState = Block.getValidBlockForPosition(blockState, world, pos);
+        if(blockState.getBlock() == Blocks.AIR || !blockState.isValidPosition(world, pos)) return null;
+
+        // Copy block properties from supporting block
+        if(targetMode) {
+            // Block properties to be copied (alignment/rotation properties)
+
+            for(Property property : new Property[]{
+                    BlockStateProperties.HORIZONTAL_FACING, BlockStateProperties.FACING, BlockStateProperties.FACING_EXCEPT_UP,
+                    BlockStateProperties.ROTATION_0_15, BlockStateProperties.AXIS, BlockStateProperties.HALF, BlockStateProperties.STAIRS_SHAPE}) {
+                if(supportingBlock.hasProperty(property) && blockState.hasProperty(property)) {
+                    blockState = blockState.with(property, supportingBlock.get(property));
+                }
+            }
+
+            // Dont dupe double slabs
+            if(supportingBlock.hasProperty(BlockStateProperties.SLAB_TYPE) && blockState.hasProperty(BlockStateProperties.SLAB_TYPE)) {
+                SlabType slabType = supportingBlock.get(BlockStateProperties.SLAB_TYPE);
+                if(slabType != SlabType.DOUBLE) blockState = blockState.with(BlockStateProperties.SLAB_TYPE, slabType);
+            }
+        }
+        return blockState;
+    }
 }