[P1 Bug] Fix softlock when a phazing attack activates a reviver seed (#4654)

* [P1 Bug] Fix softlock when a phazing attack activates a reviver seed

* Polishing tests

* Change approach to respect Parting Shot's targeting

* Tests: Added checks for correct number of Pokemon on field

src/data/move.ts

@@ -5484,37 +5484,38 @@ export class ForceSwitchOutAttr extends MoveEffectAttr {
      */
     const switchOutTarget = this.selfSwitch ? user : target;
     if (switchOutTarget instanceof PlayerPokemon) {
+      // Switch out logic for the player's Pokemon
       if (switchOutTarget.scene.getParty().filter((p) => p.isAllowedInBattle() && !p.isOnField()).length < 1) {
         return false;
       }
-      switchOutTarget.leaveField(this.switchType === SwitchType.SWITCH);
 
       if (switchOutTarget.hp > 0) {
+        switchOutTarget.leaveField(this.switchType === SwitchType.SWITCH);
         user.scene.prependToPhase(new SwitchPhase(user.scene, this.switchType, switchOutTarget.getFieldIndex(), true, true), MoveEndPhase);
         return true;
       }
       return false;
     } else if (user.scene.currentBattle.battleType !== BattleType.WILD) {
+      // Switch out logic for trainer battles
       if (switchOutTarget.scene.getEnemyParty().filter((p) => p.isAllowedInBattle() && !p.isOnField()).length < 1) {
         return false;
       }
-      // Switch out logic for trainer battles
-      switchOutTarget.leaveField(this.switchType === SwitchType.SWITCH);
 
       if (switchOutTarget.hp > 0) {
         // for opponent switching out
+        switchOutTarget.leaveField(this.switchType === SwitchType.SWITCH);
         user.scene.prependToPhase(new SwitchSummonPhase(user.scene, this.switchType, switchOutTarget.getFieldIndex(),
           (user.scene.currentBattle.trainer ? user.scene.currentBattle.trainer.getNextSummonIndex((switchOutTarget as EnemyPokemon).trainerSlot) : 0),
           false, false), MoveEndPhase);
       }
     } else {
+      // Switch out logic for everything else (eg: WILD battles)
       if (user.scene.currentBattle.waveIndex % 10 === 0) {
         return false;
       }
-      // Switch out logic for everything else (eg: WILD battles)
-      switchOutTarget.leaveField(false);
 
-      if (switchOutTarget.hp) {
+      if (switchOutTarget.hp > 0) {
+        switchOutTarget.leaveField(false);
         user.scene.queueMessage(i18next.t("moveTriggers:fled", { pokemonName: getPokemonNameWithAffix(switchOutTarget) }), null, true, 500);
 
         // in double battles redirect potential moves off fled pokemon

src/test/moves/dragon_tail.test.ts

@@ -139,4 +139,58 @@ describe("Moves - Dragon Tail", () => {
 
     expect(enemy.isFullHp()).toBe(false);
   });
+
+  it("should force a switch upon fainting an opponent normally", async () => {
+    game.override.startingWave(5)
+      .startingLevel(1000); // To make sure Dragon Tail KO's the opponent
+    await game.classicMode.startBattle([ Species.DRATINI ]);
+
+    game.move.select(Moves.DRAGON_TAIL);
+
+    await game.toNextTurn();
+
+    // Make sure the enemy switched to a healthy Pokemon
+    const enemy = game.scene.getEnemyPokemon()!;
+    expect(enemy).toBeDefined();
+    expect(enemy.isFullHp()).toBe(true);
+
+    // Make sure the enemy has a fainted Pokemon in their party and not on the field
+    const faintedEnemy = game.scene.getEnemyParty().find(p => !p.isAllowedInBattle());
+    expect(faintedEnemy).toBeDefined();
+    expect(game.scene.getEnemyField().length).toBe(1);
+  });
+
+  it("should not cause a softlock when activating an opponent trainer's reviver seed", async () => {
+    game.override.startingWave(5)
+      .enemyHeldItems([{ name: "REVIVER_SEED" }])
+      .startingLevel(1000); // To make sure Dragon Tail KO's the opponent
+    await game.classicMode.startBattle([ Species.DRATINI ]);
+
+    game.move.select(Moves.DRAGON_TAIL);
+
+    await game.toNextTurn();
+
+    // Make sure the enemy field is not empty and has a revived Pokemon
+    const enemy = game.scene.getEnemyPokemon()!;
+    expect(enemy).toBeDefined();
+    expect(enemy.hp).toBe(Math.floor(enemy.getMaxHp() / 2));
+    expect(game.scene.getEnemyField().length).toBe(1);
+  });
+
+  it("should not cause a softlock when activating a player's reviver seed", async () => {
+    game.override.startingHeldItems([{ name: "REVIVER_SEED" }])
+      .enemyMoveset(Moves.DRAGON_TAIL)
+      .enemyLevel(1000); // To make sure Dragon Tail KO's the player
+    await game.classicMode.startBattle([ Species.DRATINI, Species.BULBASAUR ]);
+
+    game.move.select(Moves.SPLASH);
+
+    await game.toNextTurn();
+
+    // Make sure the player's field is not empty and has a revived Pokemon
+    const dratini = game.scene.getPlayerPokemon()!;
+    expect(dratini).toBeDefined();
+    expect(dratini.hp).toBe(Math.floor(dratini.getMaxHp() / 2));
+    expect(game.scene.getPlayerField().length).toBe(1);
+  });
 });

src/test/moves/u_turn.test.ts

@@ -96,4 +96,23 @@ describe("Moves - U-turn", () => {
     expect(game.scene.getEnemyPokemon()!.battleData.abilityRevealed).toBe(true); // proxy for asserting ability activated
     expect(game.phaseInterceptor.log).not.toContain("SwitchSummonPhase");
   }, 20000);
+
+  it("still forces a switch if u-turn KO's the opponent", async () => {
+    game.override.startingLevel(1000); // Ensure that U-Turn KO's the opponent
+    await game.classicMode.startBattle([
+      Species.RAICHU,
+      Species.SHUCKLE
+    ]);
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    // KO the opponent with U-Turn
+    game.move.select(Moves.U_TURN);
+    game.doSelectPartyPokemon(1);
+    await game.phaseInterceptor.to(TurnEndPhase);
+    expect(enemy.isFainted()).toBe(true);
+
+    // Check that U-Turn forced a switch
+    expect(game.phaseInterceptor.log).toContain("SwitchSummonPhase");
+    expect(game.scene.getPlayerPokemon()!.species.speciesId).toBe(Species.SHUCKLE);
+  });
 });