Needs Triage Bug Report - Mechanics

[Spreek]

What type of bug are you reporting? Mechanics

What is the bug?
In gen 3 (possibly in other gens as well), we believe that Pursuit damage is not calculated correctly on switching out targets in PS!

You'll notice in the damage calculator here that when Tyranitar uses Pursuit on a switching out Gengar, the damage rolls are not identical to Crunch. This is because of the way floor functions are repeatedly applied and boosted pursuit is boosted at a different point from base power from my understanding.

Here is a desmos replicating the max damage rolls of Unboosted Pursuit, Crunch, and Boosted suit in this scenario which agrees with the damage calculator https://www.desmos.com/calculator/eheoj7ajyh. tl;dr we believe the pursuit calculations are right in the calculator and wrong on PS.

However, when boosted pursuit is actually used in PS, it appears to do damage from the Crunch damage roll table which should be impossible. Example replay https://replay.pokemonshowdown.com/gen3customgame-2488331184-csh97ite5gd9ojy3458fyf9v3ehoainpw

thanks to Johnald and Tetrafolium for their help

Are you able to replicate it? If so, how?
Use pursuit in a tyranitar vs gengar scenario and check whether the damage roll comes from the boosted pursuit rolls in the calculator or the crunch / 80 base power dark move rolls in the calculator

 

[WraxiusGaming]

Have you checked if the damage numbers are accurate to cart as well? ADV code can be jank, so could be possible that pursuit acts like crunch on switch-out in-game even though the calculation shouldn't work that way.

 

[Garpachi]

WraxiusGaming I ran the following on a Emerald ROM edited with Hex Maniac Advance for the set-up. In short, I believe this shows that Pursuit is correct in the calculator. Note that in the calcs below, the TTar is -SpA because the ROM editor does not allow you to choose natures (screenshot #3), only IV/Mon/Moveset/Items, thus the nature is randomly chosen. Min roll on neutral nature is 214 though.

0- SpA Tyranitar switching boosted Pursuit vs. 0 HP / 0 SpD Gengar: 193-228 (73.9 - 87.3%) -- guaranteed 2HKO after sandstorm damage and Leftovers recovery
Possible damage amounts: (193, 196, 198, 200, 202, 205, 207, 209, 212, 214, 216, 218, 221, 223, 225, 228)

0- SpA Tyranitar Crunch vs. 0 HP / 0 SpD Gengar: 190-224 (72.7 - 85.8%) -- guaranteed 2HKO after sandstorm damage and Leftovers recovery
Possible damage amounts: (190, 192, 194, 197, 199, 201, 203, 206, 208, 210, 212, 215, 217, 219, 221, 224)

Damage Values: 198, 205, 216, 218, 228 (See screenshot #1). See bold markings above where the Pursuit rolls match but not the Crunch rolls.