Fix ICS Crazyhouse play

The new way to associate promoted partners to pieces had woken up a latent
bug in the code that determined whether pieces in the ICS board are promoted
Pawns. This led to Pawns appearing out of nowhere on squares evacuated by
white Pawns.

diff --git a/backend.c b/backend.c
index b7f36b2..7cc8f9c 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -4907,7 +4907,7 @@ ParseBoard12 (char *string)
                && gameInfo.variant != VariantGrand&& gameInfo.variant != VariantSChess) // inherit info that ICS does not give from previous board
               for(k=0; k<ranks; k++) for(j=BOARD_LEFT; j<BOARD_RGHT; j++) {
                 ChessSquare old, new = boards[moveNum][k][j];
-                  if(fromY == DROP_RANK && k==toY && j==toX) continue; // dropped pieces always stand for themselves
+                  if(new == EmptySquare || fromY == DROP_RANK && k==toY && j==toX) continue; // dropped pieces always stand for themselves
                   old = (k==toY && j==toX) ? boards[moveNum-1][fromY][fromX] : boards[moveNum-1][k][j]; // trace back mover
                   if(old == new) continue;
                   if(old == PROMOTED(new)) boards[moveNum][k][j] = old;// prevent promoted pieces to revert to primordial ones
@@ -4915,7 +4915,7 @@ ParseBoard12 (char *string)
                       if(old < WhiteCannon || old >= BlackPawn && old < BlackCannon)
                            boards[moveNum][k][j] = PROMOTED(old); // choose correct type of Gold in promotion
                       else boards[moveNum][k][j] = old; // preserve type of Gold
-                  } else if((old == WhitePawn || old == BlackPawn) && new != EmptySquare) // Pawn promotions (but not e.p.capture!)
+                  } else if(old == WhitePawn || old == BlackPawn) // Pawn promotions (but not e.p.capture!)
                       boards[moveNum][k][j] = PROMOTED(new); // use non-primordial representation of chosen piece
               }
          } else {