Bug 88317

Summary: chess game freezes after certain move
Product: [Retired] Red Hat Linux Reporter: Jason Hibbets <jhibbets>
Component: gnuchessAssignee: Karsten Hopp <karsten>
Severity: medium Docs Contact:
Priority: medium    
Version: 8.0CC: redhat
Target Milestone: ---   
Target Release: ---   
Hardware: i586   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
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Clone Of: Environment:
Last Closed: 2003-06-03 11:06:59 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
test case none

Description Jason Hibbets 2003-04-08 21:17:54 UTC
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20021003

Description of problem:
While playing chess and you produce a ceratin move when a pawn captures another
pawn by a "back" capture the computer fails to execute another move.  Detailed
reproduction: you have a 2 white pawns and 1 black pawn on squares that connect
to each other like this:
Open | Open
Blck | Whte
Whte | Open 
and you move the furthest pawn to capture black
Whte | Open
Cap  | Open
Whte | Open

the computer (black) does not execute additional moves, black flag falls, and
game is stuck.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1.play chess
2.produce scheme above
3.capture black pawn with "back" capture

Actual Results:  Game freezes and you can no longer move.

Expected Results:  Game should continue so that I can finally beat this hard ass
computer competition.

Additional info:

Hope this helps.  It would ne nice to choose diffetent levels of play, but I
guess that is featurezilla.

Comment 1 Lee Killough 2003-04-14 02:52:34 UTC
Created attachment 91112 [details]
test case

Comment 2 Lee Killough 2003-04-14 02:54:28 UTC
Technically, the term for a "back" pawn capture as described, is "en passant".

The bug is that illegal en passant captures are not always detected correctly.

xboard does not catch all illegal moves, and gnuchess may interpret moves which
are legal syntatically but illegal semantically as bad commands, a response
which is ambiguous to xboard.


Test case (save this in bug.pgn and then run xboard -lgf bug.pgn):

1. d4 Nf6 2. Nc3 e6 3. Nf3 Bb4 4. a3 Bxc3+ 5. bxc3 O-O 6. e3 d5 7. Ne5 Ne4
8. Ng4 Nxc3 9. Qd3 Ne4 10. c4 Nc6 11. Bb2 f5 12. Ne5 Nxe5 13. dxe5 f4 14.

Comment 3 Karsten Hopp 2003-06-03 11:06:59 UTC
waiting for an upstream fix