Fix bug #43792 (no highlights after rejection of premove)

If the sending of a premove fails to add a move to the game, because
XBoard itself judges the move illegal (which could only be determined
after arrival of the opponent move, not when it was entered), XBoard
now re-applies the move highlights for that opponent move.
 This does not solve the problem yet with legality testing off,
when it later turns out the ICS rejects the move.

diff --git a/backend.c b/backend.c
index 36131f6..0624dac 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -4162,6 +4162,7 @@ read_from_ics (InputSourceRef isr, VOIDSTAR closure, char *data, int count, int
                          fprintf(debugFP, "Sending premove:\n");
                        SendToICS(str);
                      } else if (gotPremove) {
+                       int oldFMM = forwardMostMove;
                        gotPremove = 0;
                        ClearPremoveHighlights();
                        if (appData.debugMode)
@@ -4169,6 +4170,13 @@ read_from_ics (InputSourceRef isr, VOIDSTAR closure, char *data, int count, int
                           UserMoveEvent(premoveFromX, premoveFromY,
                                        premoveToX, premoveToY,
                                         premovePromoChar);
+                       if(forwardMostMove == oldFMM) { // premove was rejected, highlight last opponent move
+                         if(moveList[oldFMM-1][1] != '@')
+                           SetHighlights(moveList[oldFMM-1][0]-AAA, moveList[oldFMM-1][1]-ONE,
+                                         moveList[oldFMM-1][2]-AAA, moveList[oldFMM-1][3]-ONE);
+                         else // (drop)
+                           SetHighlights(-1, -1, moveList[oldFMM-1][2]-AAA, moveList[oldFMM-1][3]-ONE);
+                       }
                      }
                    }
 
@@ -6959,7 +6967,7 @@ int doubleClick;
 Boolean addToBookFlag;
 
 void
-UserMoveEvent(int fromX, int fromY, int toX, int toY, int promoChar)
+UserMoveEvent (int fromX, int fromY, int toX, int toY, int promoChar)
 {
     ChessMove moveType;
     ChessSquare pup;