cutoff path up until movement failure, don't throw exception and fail entire path

src/api/java/baritone/api/pathing/calc/IPath.java

@@ -52,7 +52,9 @@ public interface IPath {
      * This path is actually going to be executed in the world. Do whatever additional processing is required.
      * (as opposed to Path objects that are just constructed every frame for rendering)
      */
-    default void postProcess() {}
+    default IPath postProcess() {
+        return this;
+    }
 
     /**
      * Returns the number of positions in this path. Equivalent to {@code positions().size()}.

src/main/java/baritone/pathing/calc/Path.java

@@ -25,6 +25,7 @@ import baritone.api.utils.BetterBlockPos;
 import baritone.pathing.movement.Movement;
 import baritone.pathing.movement.Moves;
 import baritone.pathing.path.CutoffPath;
+import baritone.utils.Helper;
 import net.minecraft.client.Minecraft;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.chunk.EmptyChunk;
@@ -59,6 +60,8 @@ class Path implements IPath {
 
     private final List<Movement> movements;
 
+    private final List<PathNode> nodes;
+
     private final Goal goal;
 
     private final int numNodes;
@@ -71,8 +74,9 @@ class Path implements IPath {
         this.numNodes = numNodes;
         this.path = new ArrayList<>();
         this.movements = new ArrayList<>();
+        this.nodes = new ArrayList<>();
         this.goal = goal;
-        assemblePath(start, end);
+        assemblePath(end);
     }
 
     @Override
@@ -81,62 +85,80 @@ class Path implements IPath {
     }
 
     /**
-     * Assembles this path given the start and end nodes.
+     * Assembles this path given the end node.
      *
-     * @param start The start node
      * @param end The end node
      */
-    private void assemblePath(PathNode start, PathNode end) {
+    private void assemblePath(PathNode end) {
         if (!path.isEmpty() || !movements.isEmpty()) {
             throw new IllegalStateException();
         }
         PathNode current = end;
         LinkedList<BetterBlockPos> tempPath = new LinkedList<>();
+        LinkedList<PathNode> tempNodes = new LinkedList();
         // Repeatedly inserting to the beginning of an arraylist is O(n^2)
         // Instead, do it into a linked list, then convert at the end
-        while (!current.equals(start)) {
+        while (current != null) {
+            tempNodes.addFirst(current);
             tempPath.addFirst(new BetterBlockPos(current.x, current.y, current.z));
             current = current.previous;
         }
-        tempPath.addFirst(this.start);
         // Can't directly convert from the PathNode pseudo linked list to an array because we don't know how long it is
         // inserting into a LinkedList<E> keeps track of length, then when we addall (which calls .toArray) it's able
         // to performantly do that conversion since it knows the length.
         path.addAll(tempPath);
+        nodes.addAll(tempNodes);
     }
 
-    private void assembleMovements() {
+    private boolean assembleMovements() {
         if (path.isEmpty() || !movements.isEmpty()) {
             throw new IllegalStateException();
         }
         for (int i = 0; i < path.size() - 1; i++) {
-            movements.add(runBackwards(path.get(i), path.get(i + 1)));
+            double cost = nodes.get(i + 1).cost - nodes.get(i).cost;
+            Movement move = runBackwards(path.get(i), path.get(i + 1), cost);
+            if (move == null) {
+                return true;
+            } else {
+                movements.add(move);
             }
         }
+        return false;
+    }
 
-    private static Movement runBackwards(BetterBlockPos src, BetterBlockPos dest) { // TODO this is horrifying
+    private static Movement runBackwards(BetterBlockPos src, BetterBlockPos dest, double cost) {
         for (Moves moves : Moves.values()) {
             Movement move = moves.apply0(src);
             if (move.getDest().equals(dest)) {
-                // TODO instead of recalculating here, could we take pathNode.cost - pathNode.prevNode.cost to get the cost as-calculated?
-                move.recalculateCost(); // have to calculate the cost at calculation time so we can accurately judge whether a cost increase happened between cached calculation and real execution
+                // have to calculate the cost at calculation time so we can accurately judge whether a cost increase happened between cached calculation and real execution
+                move.override(cost);
                 return move;
             }
         }
         // this is no longer called from bestPathSoFar, now it's in postprocessing
-        throw new IllegalStateException("Movement became impossible during calculation " + src + " " + dest + " " + dest.subtract(src));
+        Helper.HELPER.logDebug("Movement became impossible during calculation " + src + " " + dest + " " + dest.subtract(src));
+        return null;
     }
 
     @Override
-    public void postProcess() {
+    public IPath postProcess() {
         if (verified) {
             throw new IllegalStateException();
         }
         verified = true;
-        assembleMovements();
-        // more post processing here
+        boolean failed = assembleMovements();
         movements.forEach(Movement::checkLoadedChunk);
+
+        if (failed) { // at least one movement became impossible during calculation
+            CutoffPath res = new CutoffPath(this, movements().size());
+            if (res.movements().size() != movements.size()) {
+                throw new IllegalStateException();
+            }
+            return res;
+        }
+        // more post processing here
         sanityCheck();
+        return this;
     }
 
     @Override

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

@@ -95,7 +95,7 @@ public abstract class Movement implements IMovement, Helper, MovementHelper {
         return getCost();
     }
 
-    protected void override(double cost) {
+    public void override(double cost) {
         this.cost = cost;
     }