Reapply #5909

[xu-shawn]

This version fixes the logic of gives_check, which was identified to be the cause of illegal moves.

thanks to @robertnurnberg for bisecting out the commit

bench 1823605

[Disservin]

could you give co-authorship to gabe on the reapply too? ^^

and please update the perft script to this, though maybe just split it into two pr's at that point

#!/bin/bash
# verify perft numbers (positions from https://www.chessprogramming.org/Perft_Results)

TESTS_FAILED=0

error()
{
  echo "perft testing failed on line $1"
  exit 1
}
trap 'error ${LINENO}' ERR

echo "perft testing started"

EXPECT_SCRIPT=$(mktemp)

cat << 'EOF' > $EXPECT_SCRIPT
#!/usr/bin/expect -f
set timeout 30
log_file -noappend [lindex $argv 3]
lassign [lrange $argv 0 3] pos depth result chess960
spawn ./stockfish
if {$chess960 == "true"} {
  send "setoption name UCI_Chess960 value true\n"
}
send "position $pos\ngo perft $depth\n"
expect {
  "Nodes searched: $result" {}
  timeout {puts "TIMEOUT: Expected $result nodes"; exit 1}
  eof {puts "EOF: Stockfish crashed"; exit 2}
}
send "quit\n"
expect eof
EOF

chmod +x $EXPECT_SCRIPT

run_test() {
  local pos="$1"
  local depth="$2"
  local expected="$3"
  local chess960="$4"
  local tmp_file=$(mktemp)

  echo -n "Testing depth $depth: ${pos:0:40}... "

  if $EXPECT_SCRIPT "$pos" "$depth" "$expected" "$chess960" "$tmp_file" > /dev/null 2>&1; then
    echo "OK"
    rm -f "$tmp_file"
  else
    local exit_code=$?
    echo "FAILED (exit code: $exit_code)"
    echo "===== Output for failed test ====="
    cat "$tmp_file"
    echo "=================================="
    rm -f "$tmp_file"
    TESTS_FAILED=1
  fi
}

# standard positions

run_test "startpos" 7 3195901860 "false"
run_test "fen r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq -" 5 193690690 "false"
run_test "fen 8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - -" 7 178633661 "false"
run_test "fen r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1" 6 706045033 "false"
run_test "fen rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8" 5 89941194 "false"
run_test "fen r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10" 5 164075551 "false"
run_test "fen r7/4p3/5p1q/3P4/4pQ2/4pP2/6pp/R3K1kr w Q - 1 3" 5 11609488 "false"

# chess960 positions

run_test "fen rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w AHah - 0 1" 6 119060324 "true"
run_test "fen 1rqbkrbn/1ppppp1p/1n6/p1N3p1/8/2P4P/PP1PPPP1/1RQBKRBN w FBfb - 0 9" 6 191762235 "true"
run_test "fen rbbqn1kr/pp2p1pp/6n1/2pp1p2/2P4P/P7/BP1PPPP1/R1BQNNKR w HAha - 0 9" 6 924181432 "true"
run_test "fen rqbbknr1/1ppp2pp/p5n1/4pp2/P7/1PP5/1Q1PPPPP/R1BBKNRN w GAga - 0 9" 6 308553169 "true"
run_test "fen 4rrb1/1kp3b1/1p1p4/pP1Pn2p/5p2/1PR2P2/2P1NB1P/2KR1B2 w D - 0 21" 6 872323796 "true"
run_test "fen 1rkr3b/1ppn3p/3pB1n1/6q1/R2P4/4N1P1/1P5P/2KRQ1B1 b Dbd - 0 14" 6 2678022813 "true"
run_test "fen qbbnrkr1/p1pppppp/1p4n1/8/2P5/6N1/PPNPPPPP/1BRKBRQ1 b FCge - 1 3" 6 521301336 "true"
run_test "fen rr6/2kpp3/1ppn2p1/p2b1q1p/P4P1P/1PNN2P1/2PP4/1K2R2R b E - 1 20" 2 1438 "true"
run_test "fen rr6/2kpp3/1ppn2p1/p2b1q1p/P4P1P/1PNN2P1/2PP4/1K2RR2 w E - 0 20" 3 37340 "true"
run_test "fen rr6/2kpp3/1ppnb1p1/p2Q1q1p/P4P1P/1PNN2P1/2PP4/1K2RR2 b E - 2 19" 4 2237725 "true"
run_test "fen rr6/2kpp3/1ppnb1p1/p4q1p/P4P1P/1PNN2P1/2PP2Q1/1K2RR2 w E - 1 19" 4 2098209 "true"
run_test "fen rr6/2kpp3/1ppnb1p1/p4q1p/P4P1P/1PNN2P1/2PP2Q1/1K2RR2 w E - 1 19" 5 79014522 "true"
run_test "fen rr6/2kpp3/1ppnb1p1/p4q1p/P4P1P/1PNN2P1/2PP2Q1/1K2RR2 w E - 1 19" 6 2998685421 "true"

rm -f $EXPECT_SCRIPT
echo "perft testing completed"

if [ $TESTS_FAILED -ne 0 ]; then
  echo "Some tests failed"
  exit 1
fi

[robertnurnberg]

I also think splitting into 2 PR's is the best way forward. So keep this for the fix, and open a new one for the perft script.