Fixes Cotton Down and Gulp Missile not interacting correctly with stat reduction prevention effects (#5841)

data/battle_scripts_1.s

@@ -1218,7 +1218,6 @@ BattleScript_StrengthSapLower:
 	playanimation BS_TARGET, B_ANIM_STATS_CHANGE, sB_ANIM_ARG1
 	printfromtable gStatDownStringIds
 	waitmessage B_WAIT_TIME_LONG
-	goto BattleScript_StrengthSapHp
 @ Drain HP without lowering a stat
 BattleScript_StrengthSapHp:
 	jumpifability BS_TARGET, ABILITY_LIQUID_OOZE, BattleScript_StrengthSapManipulateDmg
@@ -6396,18 +6395,14 @@ BattleScript_GulpMissileGulping::
 	datahpupdate BS_ATTACKER
 	tryfaintmon BS_ATTACKER
 	jumpiffainted BS_ATTACKER, TRUE, BattleScript_GulpMissileNoSecondEffectGulping
-	jumpifholdeffect BS_ATTACKER, HOLD_EFFECT_CLEAR_AMULET, BattleScript_GulpMissileNoSecondEffectGulping
-	jumpifability BS_ATTACKER, ABILITY_CLEAR_BODY, BattleScript_GulpMissileNoSecondEffectGulping
-	jumpifability BS_ATTACKER, ABILITY_FULL_METAL_BODY, BattleScript_GulpMissileNoSecondEffectGulping
-	jumpifability BS_ATTACKER, ABILITY_WHITE_SMOKE, BattleScript_GulpMissileNoSecondEffectGulping
-	jumpifflowerveilattacker BattleScript_GulpMissileNoSecondEffectGulping
 BattleScript_GulpMissileNoDmgGulping:
 	handleformchange BS_TARGET, 0
 	playanimation BS_TARGET, B_ANIM_FORM_CHANGE
 	waitanimation
 	swapattackerwithtarget @ to make gStatDownStringIds down below print the right battler
 	setstatchanger STAT_DEF, 1, TRUE
-	statbuffchange STAT_CHANGE_NOT_PROTECT_AFFECTED, BattleScript_GulpMissileGorgingTargetDefenseCantGoLower
+	statbuffchange STAT_CHANGE_NOT_PROTECT_AFFECTED | STAT_CHANGE_ALLOW_PTR, BattleScript_GulpMissileGulpingEnd
+	jumpifbyte CMP_EQUAL, cMULTISTRING_CHOOSER, B_MSG_STAT_WONT_DECREASE, BattleScript_GulpMissileGulpingTargetDefenseCantGoLower
 	setgraphicalstatchangevalues
 	playanimation BS_TARGET, B_ANIM_STATS_CHANGE, sB_ANIM_ARG1
 	printfromtable gStatDownStringIds
@@ -6419,9 +6414,11 @@ BattleScript_GulpMissileNoSecondEffectGulping:
 	playanimation BS_TARGET, B_ANIM_FORM_CHANGE
 	waitanimation
 	return
-BattleScript_GulpMissileGorgingTargetDefenseCantGoLower:
+BattleScript_GulpMissileGulpingTargetDefenseCantGoLower:
 	printstring STRINGID_STATSWONTDECREASE
 	waitmessage B_WAIT_TIME_LONG
+BattleScript_GulpMissileGulpingEnd:
+	swapattackerwithtarget @ restore the battlers, just in case
 	return
 
 BattleScript_SeedSowerActivates::
@@ -7152,7 +7149,8 @@ BattleScript_CottonDownLoop:
 	jumpiffainted BS_TARGET, TRUE, BattleScript_CottonDownLoopIncrement
 	setstatchanger STAT_SPEED, 1, TRUE
 	jumpifbyteequal gBattlerTarget, gEffectBattler, BattleScript_CottonDownLoopIncrement
-	statbuffchange STAT_CHANGE_NOT_PROTECT_AFFECTED, BattleScript_CottonDownTargetSpeedCantGoLower
+	statbuffchange STAT_CHANGE_NOT_PROTECT_AFFECTED | STAT_CHANGE_ALLOW_PTR, BattleScript_CottonDownLoopIncrement
+	jumpifbyte CMP_EQUAL, cMULTISTRING_CHOOSER, B_MSG_STAT_WONT_DECREASE, BattleScript_CottonDownTargetSpeedCantGoLower
 	setgraphicalstatchangevalues
 	playanimation BS_TARGET, B_ANIM_STATS_CHANGE, sB_ANIM_ARG1
 	printfromtable gStatDownStringIds

test/battle/ability/cotton_down.c

@@ -62,3 +62,37 @@ DOUBLE_BATTLE_TEST("Cotton Down drops speed by one of all other battlers on the
         EXPECT_EQ(opponentRight->statStages[STAT_SPEED], DEFAULT_STAT_STAGE - 1);
     }
 }
+
+DOUBLE_BATTLE_TEST("Cotton Down correctly gets blocked by stat reduction preventing abilities")
+{
+    GIVEN {
+        PLAYER(SPECIES_METAGROSS) { Ability(ABILITY_CLEAR_BODY); }
+        PLAYER(SPECIES_WYNAUT) { Item(ITEM_CLEAR_AMULET); }
+        OPPONENT(SPECIES_ELDEGOSS) { Ability(ABILITY_COTTON_DOWN); }
+        OPPONENT(SPECIES_CORVIKNIGHT) { Ability(ABILITY_MIRROR_ARMOR); }
+    } WHEN {
+        TURN { MOVE(playerLeft, MOVE_TACKLE, target: opponentLeft); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_TACKLE, playerLeft);
+        ABILITY_POPUP(opponentLeft, ABILITY_COTTON_DOWN);
+        NONE_OF {
+            ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_STATS_CHANGE, playerLeft);
+            MESSAGE("Metagross's Speed fell!");
+        }
+        ABILITY_POPUP(playerLeft, ABILITY_CLEAR_BODY);
+        NONE_OF {
+            ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_STATS_CHANGE, playerRight);
+            MESSAGE("Wynaut's Speed fell!");
+        }
+        MESSAGE("The effects of the Clear Amulet held by Wynaut prevents its stats from being lowered!");
+        NONE_OF {
+            ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_STATS_CHANGE, opponentRight);
+            MESSAGE("The opposing Corviknight's Speed fell!");
+        }
+        ABILITY_POPUP(opponentRight, ABILITY_MIRROR_ARMOR);
+    } THEN {
+        EXPECT_EQ(playerLeft->statStages[STAT_SPEED], DEFAULT_STAT_STAGE);
+        EXPECT_EQ(playerRight->statStages[STAT_SPEED], DEFAULT_STAT_STAGE);
+        EXPECT_EQ(opponentRight->statStages[STAT_SPEED], DEFAULT_STAT_STAGE);
+    }
+}

test/battle/ability/gulp_missile.c

@@ -92,6 +92,7 @@ SINGLE_BATTLE_TEST("(Gulp Missile) Transformed Cramorant deal 1/4 of damage oppo
         MESSAGE("The opposing Wobbuffet's Defense fell!");
     } THEN {
         EXPECT_EQ(gulpMissileDamage, opponent->maxHP / 4);
+        EXPECT_EQ(opponent->statStages[STAT_DEF], DEFAULT_STAT_STAGE - 1);
     }
 }
 
@@ -133,3 +134,59 @@ SINGLE_BATTLE_TEST("(Gulp Missile) triggers even if the user is fainted by oppos
         STATUS_ICON(opponent, paralysis: TRUE);
     }
 }
+
+SINGLE_BATTLE_TEST("(Gulp Missile) Transformed Cramorant Gulping lowers defense but is prevented by stat reduction preventing abilities")
+{
+    u32 species, ability;
+    PARAMETRIZE { species = SPECIES_METAGROSS; ability = ABILITY_CLEAR_BODY; }
+    PARAMETRIZE { species = SPECIES_CORVIKNIGHT; ability = ABILITY_MIRROR_ARMOR; }
+    PARAMETRIZE { species = SPECIES_CHATOT; ability = ABILITY_BIG_PECKS; }
+    GIVEN {
+        PLAYER(SPECIES_CRAMORANT) { Ability(ABILITY_GULP_MISSILE); }
+        OPPONENT(species) { Ability(ability); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_SURF); MOVE(opponent, MOVE_TACKLE); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_SURF, player);
+        HP_BAR(opponent);
+        ABILITY_POPUP(player, ABILITY_GULP_MISSILE);
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_TACKLE, opponent);
+        HP_BAR(player);
+        ABILITY_POPUP(player, ABILITY_GULP_MISSILE);
+        ABILITY_POPUP(opponent, ability);
+        NOT ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_STATS_CHANGE, opponent);
+    } THEN {
+        EXPECT_EQ(opponent->statStages[STAT_DEF], DEFAULT_STAT_STAGE);
+    }
+}
+
+SINGLE_BATTLE_TEST("(Gulp Missile) Transformed Cramorant Gulping lowers defense and still triggers other effects after")
+{
+    // Make sure attacker and target are correct after triggering the ability
+    u32 ability;
+    PARAMETRIZE { ability = ABILITY_INFILTRATOR; }
+    PARAMETRIZE { ability = ABILITY_CLEAR_BODY; }
+    GIVEN {
+        ASSUME(gMovesInfo[MOVE_TACKLE].makesContact == TRUE);
+        PLAYER(SPECIES_CRAMORANT) { Ability(ABILITY_GULP_MISSILE); Item(ITEM_ROCKY_HELMET); }
+        OPPONENT(SPECIES_DRAGAPULT) { Ability(ability); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_SURF); MOVE(opponent, MOVE_TACKLE); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_SURF, player);
+        HP_BAR(opponent);
+        ABILITY_POPUP(player, ABILITY_GULP_MISSILE);
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_TACKLE, opponent);
+        HP_BAR(player);
+        ABILITY_POPUP(player, ABILITY_GULP_MISSILE);
+        HP_BAR(opponent);
+        if (ability == ABILITY_INFILTRATOR) {
+            ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_STATS_CHANGE, opponent);
+            MESSAGE("The opposing Dragapult's Defense fell!");
+        } else {
+            ABILITY_POPUP(opponent, ABILITY_CLEAR_BODY);
+        }
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_HELD_ITEM_EFFECT, player);
+        HP_BAR(opponent);
+    }
+}