Fixed #4235

core/src/mindustry/ai/BaseAI.java

@@ -32,6 +32,7 @@ public class BaseAI{
     private static final Seq<Tile> tmpTiles = new Seq<>();
 
     private static int correct = 0, incorrect = 0;
+    private static boolean anyDrills;
 
     private int lastX, lastY, lastW, lastH;
     private boolean triedWalls, foundPath;
@@ -200,7 +201,7 @@ public class BaseAI{
         int cx = x - (int)rotator.x;
         int cy = y - (int)rotator.y;
 
-        //chekc valid placeability
+        //check valid placeability
         for(Stile tile : result.tiles){
             int realX = tile.x + cx, realY = tile.y + cy;
             if(!Build.validPlace(tile.block, data.team, realX, realY, tile.rotation)){
@@ -217,16 +218,18 @@ public class BaseAI{
 
         //make sure at least X% of resource requirements are met
         correct = incorrect = 0;
+        anyDrills = false;
 
         if(part.required instanceof Item){
             for(Stile tile : result.tiles){
                 if(tile.block instanceof Drill){
+                    anyDrills = true;
 
                     tile.block.iterateTaken(tile.x + cx, tile.y + cy, (ex, ey) -> {
                         Tile res = world.rawTile(ex, ey);
                         if(res.drop() == part.required){
                             correct ++;
-                        }else{
+                        }else if(res.drop() != null){
                             incorrect ++;
                         }
                     });
@@ -235,7 +238,7 @@ public class BaseAI{
         }
 
         //fail if not enough fit requirements
-        if((float)correct / incorrect < correctPercent){
+        if(anyDrills && (incorrect != 0 || correct == 0)){
             return false;
         }