fix: Convert UUIDField columns to uuid type for MariaDB

Converts UUIDField columns from char(32) to uuid type for MariaDB Django 5 compatibility.

This migration converts:
- openedx_ledger_transaction.idempotency_key

See: https://docs.djangoproject.com/en/5.2/releases/5.0/#migrating-uuidfield

Author: blarghmatey

openedx_ledger/__init__.py

@@ -1,4 +1,4 @@
 """
 A library that records transactions against a ledger, denominated in units of value.
 """
-__version__ = "1.6.12"
+__version__ = "1.6.13"

openedx_ledger/migrations/0016_mariadb_uuid_conversion.py

@@ -0,0 +1,44 @@
+# Generated migration for MariaDB UUID field conversion (Django 5.2)
+"""
+Migration to convert UUIDField from char(32) to uuid type for MariaDB compatibility.
+"""
+
+from django.db import migrations
+
+
+def apply_mariadb_migration(apps, schema_editor):
+    connection = schema_editor.connection
+    if connection.vendor != 'mysql':
+        return
+    with connection.cursor() as cursor:
+        cursor.execute("SELECT VERSION()")
+        version = cursor.fetchone()[0]
+        if 'mariadb' not in version.lower():
+            return
+    with connection.cursor() as cursor:
+        cursor.execute("ALTER TABLE openedx_ledger_transaction MODIFY idempotency_key uuid NULL")
+
+
+def reverse_mariadb_migration(apps, schema_editor):
+    connection = schema_editor.connection
+    if connection.vendor != 'mysql':
+        return
+    with connection.cursor() as cursor:
+        cursor.execute("SELECT VERSION()")
+        version = cursor.fetchone()[0]
+        if 'mariadb' not in version.lower():
+            return
+    with connection.cursor() as cursor:
+        cursor.execute("ALTER TABLE openedx_ledger_transaction MODIFY idempotency_key char(32) NULL")
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('openedx_ledger', '0015_add_course_run_start_date_to_transaction'),
+    ]
+    operations = [
+        migrations.RunPython(
+            code=apply_mariadb_migration,
+            reverse_code=reverse_mariadb_migration,
+        ),
+    ]