splice next into current if no backtrack, fixes #122, fixes #249

src/api/java/baritone/api/Settings.java

@@ -377,6 +377,16 @@ public class Settings {
      */
     public Setting<Boolean> walkWhileBreaking = new Setting<>(true);
 
+    /**
+     * If we are more than 500 movements into the current path, discard the oldest segments, as they are no longer useful
+     */
+    public Setting<Integer> maxPathHistoryLength = new Setting<>(500);
+
+    /**
+     * If the current path is too long, cut off this many movements from the beginning.
+     */
+    public Setting<Integer> pathHistoryCutoffAmount = new Setting<>(100);
+
     /**
      * Rescan for the goal once every 5 ticks.
      * Set to 0 to disable.

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

@@ -21,6 +21,7 @@ import baritone.api.Settings;
 import baritone.api.pathing.goals.Goal;
 import baritone.api.pathing.movement.IMovement;
 import baritone.api.utils.BetterBlockPos;
+import net.minecraft.util.math.BlockPos;
 
 import java.util.List;
 
@@ -132,4 +133,33 @@ public interface IPath {
     default IPath staticCutoff(Goal destination) {
         return this;
     }
+
+
+    /**
+     * Performs a series of checks to ensure that the assembly of the path went as expected.
+     */
+    default void sanityCheck() {
+        List<BetterBlockPos> path = positions();
+        List<IMovement> movements = movements();
+        if (!getSrc().equals(path.get(0))) {
+            throw new IllegalStateException("Start node does not equal first path element");
+        }
+        if (!getDest().equals(path.get(path.size() - 1))) {
+            throw new IllegalStateException("End node does not equal last path element");
+        }
+        if (path.size() != movements.size() + 1) {
+            throw new IllegalStateException("Size of path array is unexpected");
+        }
+        for (int i = 0; i < path.size() - 1; i++) {
+            BlockPos src = path.get(i);
+            BlockPos dest = path.get(i + 1);
+            IMovement movement = movements.get(i);
+            if (!src.equals(movement.getSrc())) {
+                throw new IllegalStateException("Path source is not equal to the movement source");
+            }
+            if (!dest.equals(movement.getDest())) {
+                throw new IllegalStateException("Path destination is not equal to the movement destination");
+            }
+        }
+    }
 }

src/main/java/baritone/behavior/PathingBehavior.java

@@ -31,9 +31,9 @@ import baritone.api.utils.BetterBlockPos;
 import baritone.api.utils.interfaces.IGoalRenderPos;
 import baritone.pathing.calc.AStarPathFinder;
 import baritone.pathing.calc.AbstractNodeCostSearch;
-import baritone.pathing.calc.CutoffPath;
 import baritone.pathing.movement.CalculationContext;
 import baritone.pathing.movement.MovementHelper;
+import baritone.pathing.path.CutoffPath;
 import baritone.pathing.path.PathExecutor;
 import baritone.utils.BlockBreakHelper;
 import baritone.utils.Helper;
@@ -156,6 +156,10 @@ public final class PathingBehavior extends Behavior implements IPathingBehavior,
                 current.onTick();
                 return;
             }
+            current = current.trySplice(next);
+            if (next != null && current.getPath().getDest().equals(next.getPath().getDest())) {
+                next = null;
+            }
             synchronized (pathCalcLock) {
                 if (isPathCalcInProgress) {
                     // if we aren't calculating right now

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

@@ -24,6 +24,7 @@ import baritone.api.pathing.movement.IMovement;
 import baritone.api.utils.BetterBlockPos;
 import baritone.pathing.movement.Movement;
 import baritone.pathing.movement.Moves;
+import baritone.pathing.path.CutoffPath;
 import net.minecraft.client.Minecraft;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.chunk.EmptyChunk;
@@ -104,32 +105,6 @@ class Path implements IPath {
         path.addAll(tempPath);
     }
 
-    /**
-     * Performs a series of checks to ensure that the assembly of the path went as expected.
-     */
-    private void sanityCheck() {
-        if (!start.equals(path.get(0))) {
-            throw new IllegalStateException("Start node does not equal first path element");
-        }
-        if (!end.equals(path.get(path.size() - 1))) {
-            throw new IllegalStateException("End node does not equal last path element");
-        }
-        if (path.size() != movements.size() + 1) {
-            throw new IllegalStateException("Size of path array is unexpected");
-        }
-        for (int i = 0; i < path.size() - 1; i++) {
-            BlockPos src = path.get(i);
-            BlockPos dest = path.get(i + 1);
-            Movement movement = movements.get(i);
-            if (!src.equals(movement.getSrc())) {
-                throw new IllegalStateException("Path source is not equal to the movement source");
-            }
-            if (!dest.equals(movement.getDest())) {
-                throw new IllegalStateException("Path destination is not equal to the movement destination");
-            }
-        }
-    }
-
     private void assembleMovements() {
         if (path.isEmpty() || !movements.isEmpty()) {
             throw new IllegalStateException();

src/main/java/baritone/pathing/path/CutoffPath.java

@@ -15,7 +15,7 @@
  * along with Baritone.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-package baritone.pathing.calc;
+package baritone.pathing.path;
 
 import baritone.api.pathing.calc.IPath;
 import baritone.api.pathing.goals.Goal;
@@ -35,11 +35,16 @@ public class CutoffPath implements IPath {
 
     private final Goal goal;
 
-    CutoffPath(IPath prev, int lastPositionToInclude) {
-        path = prev.positions().subList(0, lastPositionToInclude + 1);
-        movements = prev.movements().subList(0, lastPositionToInclude + 1);
+    public CutoffPath(IPath prev, int firstPositionToInclude, int lastPositionToInclude) {
+        path = prev.positions().subList(firstPositionToInclude, lastPositionToInclude + 1);
+        movements = prev.movements().subList(firstPositionToInclude, lastPositionToInclude);
         numNodes = prev.getNumNodesConsidered();
         goal = prev.getGoal();
+        sanityCheck();
+    }
+
+    public CutoffPath(IPath prev, int lastPositionToInclude) {
+        this(prev, 0, lastPositionToInclude);
     }
 
     @Override

src/main/java/baritone/pathing/path/PathExecutor.java

@@ -454,6 +454,43 @@ public class PathExecutor implements IPathExecutor, Helper {
         return pathPosition;
     }
 
+    public PathExecutor trySplice(PathExecutor next) {
+        if (next == null) {
+            return cutIfTooLong();
+        }
+        return SplicedPath.trySplice(path, next.path).map(path -> {
+            if (!path.getDest().equals(next.getPath().getDest())) {
+                throw new IllegalStateException();
+            }
+            PathExecutor ret = new PathExecutor(path);
+            ret.pathPosition = pathPosition;
+            ret.currentMovementOriginalCostEstimate = currentMovementOriginalCostEstimate;
+            ret.costEstimateIndex = costEstimateIndex;
+            ret.ticksOnCurrent = ticksOnCurrent;
+            return ret;
+        }).orElse(cutIfTooLong());
+    }
+
+    private PathExecutor cutIfTooLong() {
+        if (pathPosition > Baritone.settings().maxPathHistoryLength.get()) {
+            int cutoffAmt = Baritone.settings().pathHistoryCutoffAmount.get();
+            CutoffPath newPath = new CutoffPath(path, cutoffAmt, path.length() - 1);
+            if (!newPath.getDest().equals(path.getDest())) {
+                throw new IllegalStateException();
+            }
+            logDebug("Discarding earliest segment movements, length cut from " + path.length() + " to " + newPath.length());
+            PathExecutor ret = new PathExecutor(newPath);
+            ret.pathPosition = pathPosition - cutoffAmt;
+            ret.currentMovementOriginalCostEstimate = currentMovementOriginalCostEstimate;
+            if (costEstimateIndex != null) {
+                ret.costEstimateIndex = costEstimateIndex - cutoffAmt;
+            }
+            ret.ticksOnCurrent = ticksOnCurrent;
+            return ret;
+        }
+        return this;
+    }
+
     @Override
     public IPath getPath() {
         return path;

src/main/java/baritone/pathing/path/SplicedPath.java

@@ -0,0 +1,88 @@
+/*
+ * This file is part of Baritone.
+ *
+ * Baritone is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Baritone is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Baritone.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package baritone.pathing.path;
+
+import baritone.api.pathing.calc.IPath;
+import baritone.api.pathing.goals.Goal;
+import baritone.api.pathing.movement.IMovement;
+import baritone.api.utils.BetterBlockPos;
+
+import java.util.*;
+
+public class SplicedPath implements IPath {
+    private final List<BetterBlockPos> path;
+
+    private final List<IMovement> movements;
+
+    private final int numNodes;
+
+    private final Goal goal;
+
+    private SplicedPath(List<BetterBlockPos> path, List<IMovement> movements, int numNodesConsidered, Goal goal) {
+        this.path = path;
+        this.movements = movements;
+        this.numNodes = numNodesConsidered;
+        this.goal = goal;
+        sanityCheck();
+    }
+
+    @Override
+    public Goal getGoal() {
+        return goal;
+    }
+
+    @Override
+    public List<IMovement> movements() {
+        return Collections.unmodifiableList(movements);
+    }
+
+    @Override
+    public List<BetterBlockPos> positions() {
+        return Collections.unmodifiableList(path);
+    }
+
+    @Override
+    public int getNumNodesConsidered() {
+        return numNodes;
+    }
+
+    public static Optional<SplicedPath> trySplice(IPath first, IPath second) {
+        if (second == null || first == null) {
+            return Optional.empty();
+        }
+        if (!Objects.equals(first.getGoal(), second.getGoal())) {
+            return Optional.empty();
+        }
+        if (!first.getDest().equals(second.getSrc())) {
+            return Optional.empty();
+        }
+        HashSet<BetterBlockPos> a = new HashSet<>(first.positions());
+        for (int i = 1; i < second.length(); i++) {
+            if (a.contains(second.positions().get(i))) {
+                return Optional.empty();
+            }
+        }
+        List<BetterBlockPos> positions = new ArrayList<>();
+        List<IMovement> movements = new ArrayList<>();
+        positions.addAll(first.positions());
+        positions.addAll(second.positions().subList(1, second.length()));
+        movements.addAll(first.movements());
+        movements.addAll(second.movements());
+        return Optional.of(new SplicedPath(positions, movements, first.getNumNodesConsidered() + second.getNumNodesConsidered(), first.getGoal()));
+    }
+}