fix very rare null pointer exception

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

@@ -90,6 +90,7 @@ public class AStarPathFinder extends AbstractNodeCostSearch implements Helper {
         int pathingMaxChunkBorderFetch = Baritone.settings().pathingMaxChunkBorderFetch.get(); // grab all settings beforehand so that changing settings during pathing doesn't cause a crash or unpredictable behavior
         double favorCoeff = Baritone.settings().backtrackCostFavoringCoefficient.get();
         boolean minimumImprovementRepropagation = Baritone.settings().minimumImprovementRepropagation.get();
+        loopBegin();
         while (!openSet.isEmpty() && numEmptyChunk < pathingMaxChunkBorderFetch && System.nanoTime() / 1000000L - timeoutTime < 0 && !cancelRequested) {
             if (slowPath) {
                 try {
@@ -180,6 +181,7 @@ public class AStarPathFinder extends AbstractNodeCostSearch implements Helper {
         }
         System.out.println(numMovementsConsidered + " movements considered");
         System.out.println("Open set size: " + openSet.size());
+        System.out.println("PathNode map size: " + mapSize());
         System.out.println((int) (numNodes * 1.0 / ((System.nanoTime() / 1000000L - startTime) / 1000F)) + " nodes per second");
         double bestDist = 0;
         for (int i = 0; i < bestSoFar.length; i++) {

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

@@ -85,7 +85,6 @@ public abstract class AbstractNodeCostSearch implements IPathFinder {
         }
         this.cancelRequested = false;
         try {
-            currentlyRunning = this;
             Optional<IPath> path = calculate0(timeout);
             path.ifPresent(IPath::postprocess);
             isFinished = true;
@@ -97,6 +96,14 @@ public abstract class AbstractNodeCostSearch implements IPathFinder {
         }
     }
 
+    /**
+     * Don't set currentlyRunning to this until everything is all ready to go, and we're about to enter the main loop.
+     * For example, bestSoFar is null so bestPathSoFar (which gets bestSoFar[0]) could NPE if we set currentlyRunning before calculate0
+     */
+    protected void loopBegin() {
+        currentlyRunning = this;
+    }
+
     protected abstract Optional<IPath> calculate0(long timeout);
 
     /**
@@ -143,6 +150,10 @@ public abstract class AbstractNodeCostSearch implements IPathFinder {
         return Optional.ofNullable(mostRecentConsidered).map(node -> new Path(startNode, node, 0, goal));
     }
 
+    protected int mapSize() {
+        return map.size();
+    }
+
     @Override
     public Optional<IPath> bestPathSoFar() {
         if (startNode == null || bestSoFar[0] == null) {