From 6b4cbbd1629b58013eb107120ce1a04ef41d47c1 Mon Sep 17 00:00:00 2001
From: Eyal Ben-David <bdeyal@gmail.com>
Date: Tue, 19 Aug 2025 01:51:57 +0300
Subject: [PATCH] bitboard.h: check for invalid square at isAttackedBy()

This commit Fixes the following crash scenario:

In Menus:
Click Edit | Setup Position...
Click Clear
Click on White King
CRASH

This commit checks in advance for InvalidSquare in function
is AttackedBy().

The crash was: If a King is removed its square is set to InvalidSquare,
Later when checking if that square is attacked we have a crash of accessing
index beyond the board size.
---
 src/database/bitboard.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/database/bitboard.h b/src/database/bitboard.h
index 8c0baa36..b993c5d0 100644
--- a/src/database/bitboard.h
+++ b/src/database/bitboard.h
@@ -378,6 +378,10 @@ const unsigned int bb_ShiftL45[64] =
 
 inline bool BitBoard::isAttackedBy(const unsigned int color, chessx::Square square) const
 {
+    if(square == chessx::InvalidSquare)
+    {
+        return 0;
+    }
     if(bb_PawnAttacks[color ^ 1][square] & m_pawns & m_occupied_co[color])
     {
         return 1;