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Oblivion Ring loop causes crash in AI thinking

PostPosted: 17 Nov 2012, 17:26
by FranAvalon
Summary: Oblivion Ring loop causes crash in AI thinking
Description: The example loop in Oblivion Ring ruling:

"If there are no nonland permanents on the battlefield other than an Oblivion Ring, and the card it exiled was another Oblivion Ring, casting a third Oblivion Ring will result in an involuntary infinite loop that will end the game in a draw (unless someone chooses to break it by putting another nonland permanent onto the battlefield or destroying one of the Oblivion Rings, for example)."

happened to me during a game while AI was thinking. It causes immediate crash to desktop without an error message or MDMP files.

I managed to reproduce it with a simple deck. See attachment.

Steps to reproduce the crash: Let computer go first and continue playing lands. Around turn 4 or 5 CTD occurs.
Steps To Reproduce:
Additional Information: [[Oblivion Ring|OblivionRing]] ... eid=220586 [^]

I do not know how to prevent that crash due to infinite loop without checking for it specifically in AI code, because rules themselves allow that loop to happen.

But the computer keeps playing Oblivion Ring even if there are no permanents of the opponent is in play. By restricting its usage for AI only when there is a legal permanent belonging to the opponent exists(or at least another permanent that is not an Oblivion Ring exists), the crash probability might be greatly reduced. This would be a sensible strategy to play this card most of the time anyway