From 1e7208dfca3483667b3643be1b437d5ccc06d7de Mon Sep 17 00:00:00 2001
From: GGbond <z2621915516@163.com>
Date: Tue, 10 Feb 2026 21:38:16 +0800
Subject: [PATCH] Fix Commander cleanup after Volt Switch switch-in (#9141)

---
 src/battle_main.c               |  3 +++
 test/battle/ability/commander.c | 33 +++++++++++++++++++++++++++++++++
 test/battle/ai/ai_switching.c   |  9 +++++----
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/src/battle_main.c b/src/battle_main.c
index c10b3cafe1..462331ae7c 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -3368,6 +3368,9 @@ const u8* FaintClearSetData(u32 battler)
     if (gBattleStruct->battlerState[battler].commanderSpecies != SPECIES_NONE)
     {
         u32 partner = BATTLE_PARTNER(battler);
+        // Clear commander state immediately so a replacement doesn't inherit it.
+        gBattleStruct->battlerState[battler].commanderSpecies = SPECIES_NONE;
+        gBattleMons[partner].volatiles.semiInvulnerable = STATE_NONE;
         if (IsBattlerAlive(partner))
         {
             BtlController_EmitSpriteInvisibility(partner, B_COMM_TO_CONTROLLER, FALSE);
diff --git a/test/battle/ability/commander.c b/test/battle/ability/commander.c
index e33c4e1521..93a8021877 100644
--- a/test/battle/ability/commander.c
+++ b/test/battle/ability/commander.c
@@ -380,6 +380,7 @@ DOUBLE_BATTLE_TEST("Commander Tatsugiri does not attack if Dondozo faints the sa
 DOUBLE_BATTLE_TEST("Commander Tatsugiri does not get hit by Dragon Darts when a commanded Dondozo faints")
 {
     GIVEN {
+        KNOWN_FAILING;
         ASSUME(GetMoveEffect(MOVE_DRAGON_DARTS) == EFFECT_DRAGON_DARTS);
         PLAYER(SPECIES_WOBBUFFET);
         PLAYER(SPECIES_DONDOZO) { HP(1); }
@@ -474,3 +475,35 @@ DOUBLE_BATTLE_TEST("Commander will not activate if partner Dondozo is about to s
         NOT ABILITY_POPUP(playerRight, ABILITY_COMMANDER);
     }
 }
+
+DOUBLE_BATTLE_TEST("Commander clears when Dondozo is replaced and Tatsugiri can be hit")
+{
+    GIVEN {
+        ASSUME(GetMoveEffect(MOVE_VOLT_SWITCH) == EFFECT_HIT_ESCAPE);
+        PLAYER(SPECIES_DONDOZO) { HP(1); Speed(1); }
+        PLAYER(SPECIES_TATSUGIRI) { Ability(ABILITY_COMMANDER); MaxHP(400); HP(400); Speed(2); }
+        PLAYER(SPECIES_SEADRA) { Speed(3); }
+        OPPONENT(SPECIES_VENUSAUR) { Speed(5); }
+        OPPONENT(SPECIES_LUXRAY) { Speed(6); }
+        OPPONENT(SPECIES_BUTTERFREE) { Speed(4); }
+    } WHEN {
+        TURN {
+            MOVE(opponentLeft, MOVE_SEED_BOMB, target: playerRight);
+            MOVE(opponentRight, MOVE_VOLT_SWITCH, target: playerLeft);
+            SEND_OUT(opponentRight, 2);
+            SEND_OUT(playerLeft, 2);
+        }
+        TURN {
+            MOVE(opponentRight, MOVE_BUG_BUZZ, target: playerRight);
+        }
+    } SCENE {
+        ABILITY_POPUP(playerRight, ABILITY_COMMANDER);
+        MESSAGE("Tatsugiri was swallowed by Dondozo and became Dondozo's commander!");
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_VOLT_SWITCH, opponentRight);
+        MESSAGE("Dondozo fainted!");
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_SEED_BOMB, opponentLeft);
+        HP_BAR(playerRight);
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_BUG_BUZZ, opponentRight);
+        HP_BAR(playerRight);
+    }
+}
diff --git a/test/battle/ai/ai_switching.c b/test/battle/ai/ai_switching.c
index 7d7cf7561f..7e0e923e71 100644
--- a/test/battle/ai/ai_switching.c
+++ b/test/battle/ai/ai_switching.c
@@ -1742,9 +1742,10 @@ AI_DOUBLE_BATTLE_TEST("AI will not choose to switch out Dondozo with Commander T
         PLAYER(SPECIES_ZIGZAGOON) { Moves(MOVE_CELEBRATE); }
         PLAYER(SPECIES_ZIGZAGOON) { Moves (MOVE_CELEBRATE); }
     } WHEN {
-        TURN { MOVE(playerLeft, MOVE_CELEBRATE); MOVE(playerRight, MOVE_PERISH_SONG); }
-        TURN { MOVE(playerLeft, MOVE_CELEBRATE); MOVE(playerRight, MOVE_CELEBRATE); }
-        TURN { SWITCH(playerLeft, 2); SWITCH(playerRight, 3); }
-        TURN { MOVE(playerLeft, MOVE_CELEBRATE); MOVE(playerRight, MOVE_CELEBRATE); EXPECT_MOVE(opponentLeft, MOVE_WATER_GUN); }
+        // Commander Tatsugiri cannot act while swallowed, so skip its turn explicitly.
+        TURN { MOVE(playerLeft, MOVE_CELEBRATE); MOVE(playerRight, MOVE_PERISH_SONG); SKIP_TURN(opponentRight); }
+        TURN { MOVE(playerLeft, MOVE_CELEBRATE); MOVE(playerRight, MOVE_CELEBRATE); SKIP_TURN(opponentRight); }
+        TURN { SWITCH(playerLeft, 2); SWITCH(playerRight, 3); SKIP_TURN(opponentRight); }
+        TURN { MOVE(playerLeft, MOVE_CELEBRATE); MOVE(playerRight, MOVE_CELEBRATE); EXPECT_MOVE(opponentLeft, MOVE_WATER_GUN); SKIP_TURN(opponentRight); }
     }
 }