BtlController_EmitChosenMonReturnValue reads from NULL

[DizzyEggg]

Description

Vanilla issue.

BtlController_EmitChosenMonReturnValue is sometimes called with battlePartyOrder equal to NULL, which means we're reading garbage from bios(or it evaluates to zeroes, not sure)

Affected code:

void BtlController_EmitChosenMonReturnValue(u32 battler, u32 bufferId, u8 partyId, u8 *battlePartyOrder)
{
//
    for (i = 0; i < (int)ARRAY_COUNT(gBattlePartyCurrentOrder); i++)
        gBattleResources->transferBuffer[2 + i] = battlePartyOrder[i];
}

In battle_controller_player.c

static void WaitForMonSelection(u32 battler)
{
//

            BtlController_EmitChosenMonReturnValue(battler, BUFFER_B, PARTY_SIZE, NULL);
}

In battle_controller_player_partner.c

static void PlayerPartnerHandleChoosePokemon(u32 battler)
{
    BtlController_EmitChosenMonReturnValue(battler, BUFFER_B, chosenMonId, NULL);
}

I didn't look more into it, so I'm not sure if this causes anything visible in-game, but it still should be fixed.

Version

1.10.1 (Latest release)

Upcoming/master Version

No response

Discord contact info

No response

[Pawkkie]

Wonder if there's any shot this might be the mystery cause of #5589 due to the use of BtlController_EmitChosenMonReturnValue by the switching engine in OpponentHandleChoosePokemon, "reading garbage data" is an acceptable cause for "some phantom switch prompt" 🤔

[DizzyEggg]

Wonder if there's any shot this might be the mystery cause of #5589 due to the use of BtlController_EmitChosenMonReturnValue by the switching engine in OpponentHandleChoosePokemon, "reading garbage data" is an acceptable cause for "some phantom switch prompt" 🤔

That was my intuition too. We'll need to test it, because for all it's worth it could be totally harmless. OR it could be behind all of the switching weirdness which pops up once in a while