From 922a17048c07b99c5b3d315c14f6ac68c7d4e936 Mon Sep 17 00:00:00 2001
From: Wlowscha <54003515+Wlowscha@users.noreply.github.com>
Date: Thu, 27 Feb 2025 22:50:46 +0100
Subject: [PATCH] [Bug] Save data migrator to fix starters with no selectable
 forms (#5425)

Co-authored-by: Madmadness65 <59298170+Madmadness65@users.noreply.github.com>
---
 .../version_migration/versions/v1_7_0.ts      | 27 ++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/system/version_migration/versions/v1_7_0.ts b/src/system/version_migration/versions/v1_7_0.ts
index 2acb9d8151a..bdb9e6aab9f 100644
--- a/src/system/version_migration/versions/v1_7_0.ts
+++ b/src/system/version_migration/versions/v1_7_0.ts
@@ -1,8 +1,29 @@
-import { getPokemonSpeciesForm } from "#app/data/pokemon-species";
-import type { SessionSaveData } from "#app/system/game-data";
+import { getPokemonSpecies, getPokemonSpeciesForm } from "#app/data/pokemon-species";
+import { globalScene } from "#app/global-scene";
+import { DexAttr, type SessionSaveData, type SystemSaveData } from "#app/system/game-data";
 import * as Utils from "#app/utils";
 
-export const systemMigrators = [] as const;
+export const systemMigrators = [
+  /**
+   * If a starter is caught, but the only forms registered as caught are not starterSelectable,
+   * unlock the default form.
+   * @param data {@linkcode SystemSaveData}
+   */
+  function migrateUnselectableForms(data: SystemSaveData) {
+    if (data.starterData && data.dexData) {
+      Object.keys(data.starterData).forEach(sd => {
+        const caughtAttr = data.dexData[sd]?.caughtAttr;
+        const species = getPokemonSpecies(Number(sd));
+        if (caughtAttr && species.forms?.length > 1) {
+          const selectableForms = species.forms.filter((form, formIndex) => form.isStarterSelectable && (caughtAttr & globalScene.gameData.getFormAttr(formIndex)));
+          if (selectableForms.length === 0) {
+            data.dexData[sd].caughtAttr += DexAttr.DEFAULT_FORM;
+          }
+        }
+      });
+    }
+  },
+] as const;
 
 export const settingsMigrators = [] as const;