invalid FEN generation?

[mmcnl]

Hello and thank you for this valuable library!

I believe I have found a case where an invalid FEN is generated. In the example below, after the move Qxh8, black is not legally able to castle (both black rooks are no longer in their original positions) and yet the generated FEN string indicates black can castle kingside: KQk.

> game = Chess::Game.load_fen("2b1kbnr/rpq1pp1p/2n3p1/8/3Q4/2P5/PP3PPP/RN2KBNR w KQk - 0 9")
=> #<Chess::Game:0x00007f85c9bcb910>

> puts game.board
8 . . b . k b n r
7 r p q . p p . p
6 . . n . . . p .
5 . . . . . . . .
4 . . . Q . . . .
3 . . P . . . . .
2 P P . . . P P P
1 R N . . K B N R
  a b c d e f g h
=> nil

> game.move('Qxh8')
=> "Qxh8"

> game.board.to_fen
=> "2b1kbnQ/rpq1pp1p/2n3p1/8/8/2P5/PP3PPP/RN2KBNR b KQk - 0 9"

> puts game.board
8 . . b . k b n Q
7 r p q . p p . p
6 . . n . . . p .
5 . . . . . . . .
4 . . . . . . . .
3 . . P . . . . .
2 P P . . . P P P
1 R N . . K B N R
  a b c d e f g h

[pioz]

@mmcnl thank you very much for reporting this bug! This commit should now fix the issue. Let me if now works!

[mmcnl]

Thank you for the quick response! The test cases in your code look great but I will verify it works for me as well.

[mmcnl]

Yes, works perfectly, thanks again!