From 0999ca8ff919df44fca31d0319c18054ba6da411 Mon Sep 17 00:00:00 2001
From: Alex <93446519+AlexOn1ine@users.noreply.github.com>
Date: Tue, 18 Nov 2025 15:29:19 +0100
Subject: [PATCH] Shell Trap tests and Fix for Encore interaction (#8268)

Co-authored-by: PhallenTree <168426989+PhallenTree@users.noreply.github.com>
---
 src/battle_script_commands.c         | 16 +++----
 test/battle/move_effect/shell_trap.c | 65 ++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 9 deletions(-)

diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index e100d3a9ca..be70970fa7 100755
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -11527,14 +11527,16 @@ static void Cmd_trysetencore(void)
     }
 
     if ((IsMoveEncoreBanned(gLastMoves[gBattlerTarget]))
+     || i == MAX_MON_MOVES
      || gLastMoves[gBattlerTarget] == MOVE_NONE
-     || gLastMoves[gBattlerTarget] == MOVE_UNAVAILABLE)
+     || gLastMoves[gBattlerTarget] == MOVE_UNAVAILABLE
+     || gBattleMons[gBattlerTarget].pp[i] == 0
+     || gDisableStructs[gBattlerTarget].encoredMove != MOVE_NONE
+     || GetMoveEffect(gChosenMoveByBattler[gBattlerTarget]) == EFFECT_SHELL_TRAP)
     {
-        i = MAX_MON_MOVES;
+        gBattlescriptCurrInstr = cmd->failInstr;
     }
-
-    if (gDisableStructs[gBattlerTarget].encoredMove == MOVE_NONE
-        && i != MAX_MON_MOVES && gBattleMons[gBattlerTarget].pp[i] != 0)
+    else
     {
         gDisableStructs[gBattlerTarget].encoredMove = gBattleMons[gBattlerTarget].moves[i];
         gDisableStructs[gBattlerTarget].encoredMovePos = i;
@@ -11552,10 +11554,6 @@ static void Cmd_trysetencore(void)
             gDisableStructs[gBattlerTarget].encoreTimer = 3;
         gBattlescriptCurrInstr = cmd->nextInstr;
     }
-    else
-    {
-        gBattlescriptCurrInstr = cmd->failInstr;
-    }
 }
 
 static void Cmd_painsplitdmgcalc(void)
diff --git a/test/battle/move_effect/shell_trap.c b/test/battle/move_effect/shell_trap.c
index 903f984929..f3f0068d6f 100644
--- a/test/battle/move_effect/shell_trap.c
+++ b/test/battle/move_effect/shell_trap.c
@@ -214,3 +214,68 @@ SINGLE_BATTLE_TEST("Shell Trap activates if user is hit with a physical move but
         HP_BAR(opponent);
     }
 }
+
+SINGLE_BATTLE_TEST("Encore fails if target has active Shell Trap waiting")
+{
+    GIVEN {
+        ASSUME(GetMoveEffect(MOVE_ENCORE) == EFFECT_ENCORE);
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE); }
+        TURN { MOVE(player, MOVE_SHELL_TRAP); MOVE(opponent, MOVE_ENCORE); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_CELEBRATE, player);
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_CELEBRATE, opponent);
+        MESSAGE("Wobbuffet set a shell trap!");
+        NONE_OF {
+            ANIMATION(ANIM_TYPE_MOVE, MOVE_ENCORE, opponent);
+            ANIMATION(ANIM_TYPE_MOVE, MOVE_SHELL_TRAP, player);
+        }
+    }
+}
+
+SINGLE_BATTLE_TEST("Shell Trap fails if an other -3 or lower priority Move is used")
+{
+    GIVEN {
+        ASSUME(GetMovePriority(MOVE_DRAGON_TAIL) <= -3);
+        PLAYER(SPECIES_WOBBUFFET);
+        PLAYER(SPECIES_WYNAUT);
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN {
+            MOVE(player, MOVE_SHELL_TRAP);
+            MOVE(opponent, MOVE_DRAGON_TAIL);
+        }
+    } SCENE {
+        MESSAGE("Wobbuffet set a shell trap!");
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_DRAGON_TAIL, opponent);
+        NOT ANIMATION(ANIM_TYPE_MOVE, MOVE_SHELL_TRAP, player);
+    }
+}
+
+DOUBLE_BATTLE_TEST("Shell Trap does not trigger when hit into Substitute")
+{
+    GIVEN {
+        ASSUME(GetMoveCategory(MOVE_DOUBLE_EDGE) == DAMAGE_CATEGORY_PHYSICAL);
+        PLAYER(SPECIES_WYNAUT);
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_SNORLAX);
+        OPPONENT(SPECIES_WYNAUT);
+    } WHEN {
+        TURN { MOVE(playerLeft, MOVE_SUBSTITUTE); }
+        TURN {
+            MOVE(playerLeft, MOVE_SHELL_TRAP);
+            MOVE(opponentLeft, MOVE_DOUBLE_EDGE, target: playerLeft);
+            MOVE(opponentRight, MOVE_SCRATCH, target: playerLeft);
+        }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_SUBSTITUTE, playerLeft);
+        MESSAGE("Wynaut set a shell trap!");
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_DOUBLE_EDGE, opponentLeft);
+        MESSAGE("Wynaut's substitute faded!");
+        NOT ANIMATION(ANIM_TYPE_MOVE, MOVE_SHELL_TRAP, playerLeft);
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_SCRATCH, opponentRight);
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_SHELL_TRAP, playerLeft);
+    }
+}