Game import validation

[dlbbld]

When importing a game played beyond checkmate or stalemate, the import validation says the below, which is fine:

The PGN contains illegal and/or ambiguous moves.

However, the game passes the validation when played beyond fivefold repetition, seventy-five moves without a pawn move or capture and a dead position.

However, per the FIDE rules, a game ends immediately for these cases. Therefore, I want to discuss adding validation for these cases, which is in line with the existing validation.

[niklasf]

Especially for imported real world games I think it's best to not enforce this. Historically, these rules didn't always exist, and even today a game might be continued for a few more moves, if the arbiter doesn't step in.

[dlbbld]

Thanks for the feedback. I looked at it from an engine view. Stockfish does not take moves beyond checkmate. Similarly, an engine can validly refuse moves after these situations, for the game has ended by the FIDE rules.

Though Stockfish might never do so, I think it is still worth considering. For example, the analysis board freezes after fifty moves without a pawn move or capture. Just as an example, implementing these rules is quite vulnerable to side effects. So, I think it's still worth mentioning that games played beyond these situations can flow into Lichess, while when playing in Lichess, that can never happen.

[niklasf]

👍, definitely something to be aware of. Even games played on Lichess weren't always played under these rules.