fix passable and replacable checks for snow in cached chunks, fixes #87

src/main/java/baritone/chunk/ChunkPacker.java

@@ -112,7 +112,6 @@ public final class ChunkPacker implements Helper {
         if (MovementHelper.avoidWalkingInto(block)) {
             return PathingBlockType.AVOID;
         }
-
         // We used to do an AABB check here
         // however, this failed in the nether when you were near a nether fortress
         // because fences check their adjacent blocks in the world for their fence connection status to determine AABB shape

src/main/java/baritone/pathing/movement/MovementHelper.java

@@ -33,6 +33,7 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.util.NonNullList;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.RayTraceResult;
+import net.minecraft.world.chunk.EmptyChunk;
 
 import java.util.Optional;
 
@@ -75,16 +76,48 @@ public interface MovementHelper extends ActionCosts, Helper {
                 || block instanceof BlockEndPortal) {//you can't actually walk through a lilypad from the side, and you shouldn't walk through fire
             return false;
         }
+        if (block instanceof BlockDoor) {
+            if (block == Blocks.IRON_DOOR) {
+                return false;
+            }
+            return true; // we can just open the door
+        }
+        if (block instanceof BlockSnow || block instanceof BlockFenceGate || block instanceof BlockTrapDoor) {
+            // we've already checked doors
+            // so the only remaining dynamic isPassables are snow, fence gate, and trapdoor
+            // if they're cached as a top block, we don't know their metadata
+            // default to true (mostly because it would otherwise make long distance pathing through snowy biomes impossible)
+            if (mc.world.getChunk(pos) instanceof EmptyChunk) {
+                return true;
+            }
+        }
         IBlockState up = BlockStateInterface.get(pos.up());
         if (BlockStateInterface.isFlowing(state) || up.getBlock() instanceof BlockLiquid || up.getBlock() instanceof BlockLilyPad) {
             return false; // Don't walk through flowing liquids
         }
-        if (block instanceof BlockDoor && !Blocks.IRON_DOOR.equals(block)) {
-            return true; // we can just open the door
-        }
         return block.isPassable(mc.world, pos);
     }
 
+    static boolean isReplacable(BlockPos pos, IBlockState state) {
+        // for MovementTraverse and MovementAscend
+        // block double plant defaults to true when the block doesn't match, so don't need to check that case
+        // all other overrides just return true or false
+        // the only case to deal with is snow
+        /*
+         *  public boolean isReplaceable(IBlockAccess worldIn, BlockPos pos)
+         *     {
+         *         return ((Integer)worldIn.getBlockState(pos).getValue(LAYERS)).intValue() == 1;
+         *     }
+         */
+        if (state.getBlock() instanceof BlockSnow) {
+            // as before, default to true (mostly because it would otherwise make long distance pathing through snowy biomes impossible)
+            if (mc.world.getChunk(pos) instanceof EmptyChunk) {
+                return true;
+            }
+        }
+        return state.getBlock().isReplaceable(mc.world, pos);
+    }
+
     static boolean isDoorPassable(BlockPos doorPos, BlockPos playerPos) {
         IBlockState door = BlockStateInterface.get(doorPos);
         if (!(door.getBlock() instanceof BlockDoor)) {

src/main/java/baritone/pathing/movement/movements/MovementAscend.java

@@ -74,11 +74,10 @@ public class MovementAscend extends Movement {
     protected double calculateCost(CalculationContext context) {
         IBlockState toPlace = BlockStateInterface.get(positionsToPlace[0]);
         if (!MovementHelper.canWalkOn(positionsToPlace[0], toPlace)) {
-            if (!BlockStateInterface.isAir(toPlace) && !BlockStateInterface.isWater(toPlace.getBlock())) {
-                // TODO replace this check with isReplacable or similar
+            if (!context.hasThrowaway()) {
                 return COST_INF;
             }
-            if (!context.hasThrowaway()) {
+            if (!BlockStateInterface.isAir(toPlace) && !BlockStateInterface.isWater(toPlace.getBlock()) && !MovementHelper.isReplacable(positionsToPlace[0], toPlace)) {
                 return COST_INF;
             }
             for (BlockPos against1 : against) {

src/main/java/baritone/pathing/movement/movements/MovementTraverse.java

@@ -107,7 +107,7 @@ public class MovementTraverse extends Movement {
                 return COST_INF;
             }
             IBlockState pp0 = BlockStateInterface.get(positionsToPlace[0]);
-            if (pp0.getBlock().equals(Blocks.AIR) || (!BlockStateInterface.isWater(pp0.getBlock()) && pp0.getBlock().isReplaceable(Minecraft.getMinecraft().world, positionsToPlace[0]))) {
+            if (pp0.getBlock().equals(Blocks.AIR) || (!BlockStateInterface.isWater(pp0.getBlock()) && MovementHelper.isReplacable(positionsToPlace[0], pp0))) {
                 if (!context.hasThrowaway()) {
                     return COST_INF;
                 }