DroidFish: A mating move could be added more than once to the game tree.

DroidFish/src/org/petero/droidfish/gamelogic/Game.java

@@ -88,6 +88,7 @@ public class Game {
         updateTimeControl(false);
     }
 
+    /** Set game state from a PGN string. */
     final public boolean readPGN(String pgn, PGNOptions options) throws ChessParseError {
         boolean ret = tree.readPGN(pgn, options);
         if (ret) {
@@ -192,13 +193,18 @@ public class Game {
                     nVars = varMoves.size();
                 }
             }
+            Boolean gameEndingMove = null;
             for (varNo = 0; varNo < nVars; varNo++) {
                 if (varMoves.get(varNo).equals(m)) {
                     boolean match = true;
                     if (playerAction.isEmpty()) {
-                        tree.goForward(varNo, false);
+                        if (gameEndingMove == null)
-                        match = tree.getGameState() == GameState.ALIVE;
+                            gameEndingMove = gameEndingMove(m);
-                        tree.goBack();
+                        if (!gameEndingMove) {
+                            tree.goForward(varNo, false);
+                            match = tree.getGameState() == GameState.ALIVE;
+                            tree.goBack();
+                        }
                     }
                     if (match) {
                         movePresent = true;
@@ -222,6 +228,16 @@ public class Game {
         pendingDrawOffer = false;
     }
 
+    /** Return true if move "m" in the current position ends the game (mate or stalemate). */
+    private boolean gameEndingMove(Move m) {
+        Position pos = currPos();
+        UndoInfo ui = new UndoInfo();
+        pos.makeMove(m, ui);
+        boolean gameEnd = MoveGen.instance.legalMoves(pos).isEmpty();
+        pos.unMakeMove(m, ui);
+        return gameEnd;
+    }
+
     private final void updateTimeControl(boolean discardElapsed) {
         Position currPos = currPos();
         int move = currPos.fullMoveCounter;

DroidFishTest/src/org/petero/droidfish/gamelogic/GameTest.java

@@ -20,6 +20,8 @@ package org.petero.droidfish.gamelogic;
 
 import java.util.ArrayList;
 
+import org.petero.droidfish.PGNOptions;
+
 import junit.framework.TestCase;
 
 
@@ -485,4 +487,78 @@ public class GameTest extends TestCase {
         expectedPos = TextIO.readFEN(TextIO.startPosFEN);
         assertEquals(expectedPos, hist.first);
     }
+
+    public final void testDuplicateMoves() throws ChessParseError {
+        PGNOptions options = new PGNOptions();
+        options.imp.variations = true;
+        options.imp.comments = true;
+        options.imp.nag = true;
+
+        {
+            Game game = new Game(null, new TimeControlData());
+            boolean res = game.readPGN("[Event \"\"]\n[Result \"0-1\"]\n\ne4 0-1", options);
+            assertEquals(true, res);
+            assertEquals("e4", GameTreeTest.getVariationsAsString(game.tree));
+
+            Pair<Boolean,Move> p = game.processString("e4");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("e2e4"), p.second);
+            game.undoMove();
+            assertEquals("e4 e4", GameTreeTest.getVariationsAsString(game.tree));
+
+            p = game.processString("e4");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("e2e4"), p.second);
+            game.undoMove();
+            assertEquals("e4 e4", GameTreeTest.getVariationsAsString(game.tree));
+
+            p = game.processString("d4");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("d2d4"), p.second);
+            game.undoMove();
+            assertEquals("d4 e4 e4", GameTreeTest.getVariationsAsString(game.tree));
+        }
+        {
+            Game game = new Game(null, new TimeControlData());
+            game.setPos(TextIO.readFEN("k7/5R2/6R1/2K5/8/8/8/8 w - - 0 1"));
+            Pair<Boolean,Move> p = game.processString("Rg8");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("g6g8"), p.second);
+            game.undoMove();
+            assertEquals("Rg8#", GameTreeTest.getVariationsAsString(game.tree));
+
+            p = game.processString("Rg8");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("g6g8"), p.second);
+            game.undoMove();
+            assertEquals("Rg8#", GameTreeTest.getVariationsAsString(game.tree));
+
+            p = game.processString("Rgg7");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("g6g7"), p.second);
+            game.undoMove();
+            assertEquals("Rgg7 Rg8#", GameTreeTest.getVariationsAsString(game.tree));
+        }
+        {
+            Game game = new Game(null, new TimeControlData());
+            game.setPos(TextIO.readFEN("k7/8/1K6/8/8/8/2Q5/8 w - - 0 1"));
+            Pair<Boolean,Move> p = game.processString("Qc7");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("c2c7"), p.second);
+            game.undoMove();
+            assertEquals("Qc7", GameTreeTest.getVariationsAsString(game.tree));
+
+            p = game.processString("Qc7");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("c2c7"), p.second);
+            game.undoMove();
+            assertEquals("Qc7", GameTreeTest.getVariationsAsString(game.tree));
+
+            p = game.processString("Qc8");
+            assertEquals(true, (boolean)p.first);
+            assertEquals(TextIO.UCIstringToMove("c2c8"), p.second);
+            game.undoMove();
+            assertEquals("Qc8# Qc7", GameTreeTest.getVariationsAsString(game.tree));
+        }
+    }
 }

DroidFishTest/src/org/petero/droidfish/gamelogic/GameTreeTest.java

@@ -242,7 +242,7 @@ public class GameTreeTest extends TestCase {
         assertEquals(0, gt.currentNode.defaultChild);
     }
 
-    private final String getVariationsAsString(GameTree gt) {
+    final static String getVariationsAsString(GameTree gt) {
         StringBuilder ret = new StringBuilder();
         List<Move> vars = gt.variations();
         for (int i = 0; i < vars.size(); i++) {