Fix engine stall on perpetual-check evasion

[xboard.git] / backend.c

diff --git a/backend.c b/backend.c
index 031141a..53799ec 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -6839,11 +6839,8 @@ Adjudicate(ChessProgramState *cps)
                         if( rights == 0 && ++count > appData.drawRepeats-2 && canAdjudicate
                             && appData.drawRepeats > 1) {
                              /* adjudicate after user-specified nr of repeats */
-                            if(engineOpponent) {
-                              SendToProgram("force\n", engineOpponent); // suppress reply
-                              SendMoveToProgram(forwardMostMove-1, engineOpponent); /* make sure opponent gets to see move */
-                            }
-                             ShowMove(fromX, fromY, toX, toY); /*updates currentMove*/
+                            int result = GameIsDrawn;
+                            char *details = "XBoard adjudication: repetition draw";
                             if(gameInfo.variant == VariantXiangqi && appData.testLegality) { 
                                // [HGM] xiangqi: check for forbidden perpetuals
                                int m, ourPerpetual = 1, hisPerpetual = 1;
@@ -6856,27 +6853,31 @@ Adjudicate(ChessProgramState *cps)
                                if(appData.debugMode) fprintf(debugFP, "XQ perpetual test, our=%d, his=%d\n",
                                                                        ourPerpetual, hisPerpetual);
                                if(ourPerpetual && !hisPerpetual) { // we are actively checking him: forfeit
-                                   GameEnds( WhiteOnMove(forwardMostMove) ? WhiteWins : BlackWins, 
-                                          "Xboard adjudication: perpetual checking", GE_XBOARD );
-                                   return 1;
-                               }
-                               if(hisPerpetual && !ourPerpetual)   // he is checking us, but did not repeat yet
+                                   result = WhiteOnMove(forwardMostMove) ? WhiteWins : BlackWins;
+                                   details = "Xboard adjudication: perpetual checking";
+                               } else
+                               if(hisPerpetual && !ourPerpetual) { // he is checking us, but did not repeat yet
                                    break; // (or we would have caught him before). Abort repetition-checking loop.
+                               } else
                                // Now check for perpetual chases
                                if(!ourPerpetual && !hisPerpetual) { // no perpetual check, test for chase
                                    hisPerpetual = PerpetualChase(k, forwardMostMove);
                                    ourPerpetual = PerpetualChase(k+1, forwardMostMove);
                                    if(ourPerpetual && !hisPerpetual) { // we are actively chasing him: forfeit
-                                       GameEnds( WhiteOnMove(forwardMostMove) ? WhiteWins : BlackWins, 
-                                                     "Xboard adjudication: perpetual chasing", GE_XBOARD );
-                                       return 1;
-                                   }
+                                       result = WhiteOnMove(forwardMostMove) ? WhiteWins : BlackWins;
+                                       details = "Xboard adjudication: perpetual chasing";
+                                   } else
                                    if(hisPerpetual && !ourPerpetual)   // he is chasing us, but did not repeat yet
                                        break; // Abort repetition-checking loop.
                                }
                                // if neither of us is checking or chasing all the time, or both are, it is draw
                             }
-                             GameEnds( GameIsDrawn, "Xboard adjudication: repetition draw", GE_XBOARD );
+                            if(engineOpponent) {
+                              SendToProgram("force\n", engineOpponent); // suppress reply
+                              SendMoveToProgram(forwardMostMove-1, engineOpponent); /* make sure opponent gets to see move */
+                            }
+                             ShowMove(fromX, fromY, toX, toY); /*updates currentMove*/
+                             GameEnds( result, details, GE_XBOARD );
                              return 1;
                         }
                         if( rights == 0 && count > 1 ) /* occurred 2 or more times before */