[Bug-XBoard] Winboard bugs

[John Widman]

Hello Tim,

 

First, thank you greatly for your marvelous Winboard which has enriched the lives of so many.

 

I have noted a castling bug, which persists into the latest version 4.2.7.  I noticed this when playing with Usurper, which is a very weak engine which does not know the castling rules correctly, or perhaps not at all.

 

It seems Usurper will violate every or almost every prohibition on castling from time to time (like castling to get out of check, castling through check), and it seems that Winboard catches some of these.  However, when Usurper moves its king, then moves it back again to a position from which castling is legal (not accounting that it has moved its king previously), Winboard allows this.

 

Another interesting example is a game with another of the weaker WinBoard programs which, although behind, succeeded in advancing a pawn to the eighth rank.  Seeing that promotion to a queen (or any other piece) still resulted in its checkmate, it promoted to a second King!  Very creative, I thought.  What good are rules if you can’t bend them once in awhile for a favorite opponent?  So I played on.  When I tried to checkmate one king, the other one would move.  Hmm. Maybe I had to checkmate both kings with the same move.  Not so easy.  Then I thought I should just capture one king first, then checkmate the other. However, this attempt caused it to crash.

 

Perhaps the responsibility for monitoring legal moves rests with the engines and not Winboard.  If so, my comments are not of value to you and I apologize.

 

Sincerely,

 

John Widman