No exception raised when fen position is wrong about stockfish HOT 9 CLOSED

Thank you. I'll fix it soon.

from stockfish.

I tried your example:

wrong_fen = '3kk3/8/8/8/8/8/8/3KK3 w - - 0 0'
s = Stockfish()
print('stockfish created')

s.set_fen_position(wrong_fen)
print('board position set')
move = s.get_best_move()
print('best move is {}'.format(move))

Output:

stockfish created
board position set
best move is d1c1

But even more problematic is that the call get_best_move doesn't return at all

I can't confirm it

from stockfish.

I guess we got different behaviors because we are on different systems. I am on Fedora 32, using Stockfish 10 and Python 3.8.

Anyway, in your case you got a "best move" in return, but I think there should be some exception instead, because the board has 4 kings, hence it is an impossible position.

from stockfish.

Anyway, in your case you got a "best move" in return, but I think there should be some exception instead, because the board has 4 kings, hence it is an impossible position.

but stockfish engine returns best move, doesn't it?

from stockfish.

In my case it doesn't return anything and it hangs forever.

If in your case it returned a move, I don't understand how that would be correct, since there is a forbidden position on the board.

from stockfish.

Is this test case correct?

#37

from stockfish.

I admit I am no expert in chess engines.

However it seems inappropriate to me to expect a move like "d1e2" given a wrong board position. In my opinion, it would be more appropriate if an exception was raised when attempting to set a wrong position.

from stockfish.

an exception was raised when attempting to set a wrong position

This package is not chess engine, it's only the wrapper for stockfish chess engine

If stockfish dont rise an excpetion for wrong position, I think we should not do it also.

from stockfish.

I understand this is a wrapper. Chess engines generally communicate to the user through the UCI, hence they cannot raise exceptions. This wrapper communicates to its users through python, so it would be possible to raise an exception. I understand this is a design choice and you are free to make your own decision.

from stockfish.