Bug 326932

Summary:	Solver reports winnable game 1268426203 as unwinnable
Product:	[Applications] kpat	Reporter:	Martin Riethmayer <ripper>
Component:	solver	Assignee:	Stephan Kulow <coolo>
Status:	RESOLVED FIXED
Severity:	wishlist	CC:	kde-games-bugs-null, petzke, ripper
Priority:	NOR
Version First Reported In:	3.6
Target Milestone:	---
Platform:	Kubuntu
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Saved game in "unwinnable" state The solution to the saved "unwinnable" game

Description Martin Riethmayer 2013-10-31 09:31:24 UTC

In the saved game, the solver says, the game is unwinnable, but it actually is winnable. Two moves (Col 9 -> Col 10, Col 1 -> Col 10) make the solver correctly report the game as winnable. These two moves are actually reversible (so you could get an infinite loop of solvable / not solvable).

I'm attaching the save game (sorry, no clue how I got to that point) and a text file with the steps to actually win the game.

Reproducible: Always

Steps to Reproduce:
1. Open saved game
2. See "unwinnable" message
3. Use attached solution to win the game
Actual Results:  
Game is winnable

Expected Results:  
Solver should not claim it's unwinnable - at worst it should say "undeterminable", at best it should "know" that the game is winnable

Comment 1 Martin Riethmayer 2013-10-31 09:32:06 UTC

Created attachment 83248 [details]
Saved game in "unwinnable" state

Comment 2 Martin Riethmayer 2013-10-31 09:32:32 UTC

Created attachment 83249 [details]
The solution to the saved "unwinnable" game

Comment 3 Kai Petzke 2014-11-06 09:58:35 UTC

Togehter with a playability upgrade for spider (see Bug report 248859) I also submitted a rewrite of large portions of the spider specific part of the solver, that - according to my tests - fixes this issue. After loading, the game is no longer reported as "unsolvable", but as "undeterminable". After the first suggested move (Col 9 -> Col 10), the game is reported as "solvable".

Comment 4 Martin Riethmayer 2017-05-16 10:59:30 UTC

Sorry for the extremely late comment: when loading the game, Kpatience (3.6, KF 5.33, Qt 5.7.1) on KDE Neon User stable (Plasma 5.9.5) still reports the saved game as unwinnable.

Comment 5 Stephan Kulow 2023-02-28 14:40:21 UTC

The new solver (417bdc2ec4fa474e3c62063790cae72bc171d7e9) will now say "unable to determine if winnable" as it does not attempt to split the S4 from the S5 (the first move in your solution). Once that move is done, it switches to "is winnable"