From fc872b481e77e07676e1d9021468c0016b52b9e1 Mon Sep 17 00:00:00 2001
From: Eduardo Quezada <eduardo602002@gmail.com>
Date: Sun, 27 Apr 2025 09:27:21 -0400
Subject: [PATCH] Fix `FORM_CHANGE_ITEM_HOLD` bug manifested during `givemon`
 (#6702)

---
 src/pokemon.c  | 18 +++++++++++++++++-
 test/pokemon.c | 17 +++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/pokemon.c b/src/pokemon.c
index f09dbacab5..300b57e81d 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -6559,7 +6559,23 @@ u32 GetFormChangeTargetSpeciesBoxMon(struct BoxPokemon *boxMon, u16 method, u32
                 case FORM_CHANGE_ITEM_HOLD:
                     if ((heldItem == formChanges[i].param1 || formChanges[i].param1 == ITEM_NONE)
                      && (ability == formChanges[i].param2 || formChanges[i].param2 == ABILITY_NONE))
-                        targetSpecies = formChanges[i].targetSpecies;
+                    {
+                        // This is to prevent reverting to base form when giving the item to the corresponding form.
+                        // Eg. Giving a Zap Plate to an Electric Arceus without an item (most likely to happen when using givemon)
+                        bool32 currentItemForm = FALSE;
+                        for (int j = 0; formChanges[j].method != FORM_CHANGE_TERMINATOR; j++)
+                        {
+                            if (species == formChanges[j].targetSpecies
+                                && formChanges[j].param1 == heldItem
+                                && formChanges[j].param1 != ITEM_NONE)
+                            {
+                                currentItemForm = TRUE;
+                                break;
+                            }
+                        }
+                        if (!currentItemForm)
+                            targetSpecies = formChanges[i].targetSpecies;
+                    }
                     break;
                 case FORM_CHANGE_ITEM_USE:
                     if (arg == formChanges[i].param1)
diff --git a/test/pokemon.c b/test/pokemon.c
index 16aadee798..dbb88081cf 100644
--- a/test/pokemon.c
+++ b/test/pokemon.c
@@ -256,6 +256,23 @@ TEST("givemon respects perfectIVCount")
     }
 }
 
+TEST("givemon respects FORM_CHANGE_ITEM_HOLD")
+{
+    ZeroPlayerPartyMons();
+
+    RUN_OVERWORLD_SCRIPT(
+        givemon SPECIES_ARCEUS_NORMAL, 100, item=ITEM_ZAP_PLATE;
+        givemon SPECIES_ARCEUS_GRASS, 100, item=ITEM_ZAP_PLATE;
+        givemon SPECIES_ARCEUS_ELECTRIC, 100, item=ITEM_ZAP_PLATE;
+        givemon SPECIES_GIRATINA_ORIGIN, 100, item=ITEM_POTION;
+    );
+
+    EXPECT_EQ(GetMonData(&gPlayerParty[0], MON_DATA_SPECIES), SPECIES_ARCEUS_ELECTRIC);
+    EXPECT_EQ(GetMonData(&gPlayerParty[1], MON_DATA_SPECIES), SPECIES_ARCEUS_ELECTRIC);
+    EXPECT_EQ(GetMonData(&gPlayerParty[2], MON_DATA_SPECIES), SPECIES_ARCEUS_ELECTRIC);
+    EXPECT_EQ(GetMonData(&gPlayerParty[3], MON_DATA_SPECIES), SPECIES_GIRATINA_ALTERED);
+}
+
 TEST("givemon [moves]")
 {
     ZeroPlayerPartyMons();