Elder Deep-Fiend issue

[jeffwadsworth]

While testing Elder Deep-Fiend, I noticed serious issues with slowdown; eventually the client froze. It appears to be an issue with its CastSourceTriggeredAbility(). To replicate, just have it in your hand and play something like Biolume Egg.

[[Elder Deep-Fiend]] [[Biolume Egg]]

[github-actions]

Elder Deep-Fiend - (Gatherer) (Scryfall) (EDHREC)

{8}
Creature — Eldrazi Octopus
5/6
Flash
Emerge {5}{U}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, tap up to four target permanents.

Biolume Egg // Biolume Serpent - (Gatherer) (Scryfall) (EDHREC)

{2}{U}
Creature — Serpent Egg
0/4
Defender
When Biolume Egg enters the battlefield, scry 2.
When you sacrifice Biolume Egg, return it to the battlefield transformed under its owner's control at the beginning of the next end step.
🔄
Creature — Serpent
4/4
Sacrifice two Islands: Biolume Serpent can't be blocked this turn.

[Alex-Vasile]

Do you think it's an AI-related slowdown?

[jeffwadsworth]

I didn't test human only. I will check that.

[jeffwadsworth]

Yes, apparently AI related. So many options for the tap.

[Alex-Vasile]

Seems like a lesser version of #9438.

That class of "Tap UP TO" effects need their AI handing code re-written to have AI pick the worst case scenario using a heuristic rather than check all possible combinations.

[Alex-Vasile]

Combining this into #9539