fix: dont auto drop manually created index on text types (#15739)

frappe/database/schema.py

@@ -222,7 +222,7 @@ class DbColumn:
 		# unique
 		if ((self.unique and not current_def['unique']) and column_type not in ('text', 'longtext')):
 			self.table.add_unique.append(self)
-		elif (current_def['unique'] and not self.unique):
+		elif (current_def['unique'] and not self.unique) and column_type not in ('text', 'longtext'):
 			self.table.drop_unique.append(self)
 
 		# default
@@ -233,7 +233,7 @@ class DbColumn:
 			self.table.set_default.append(self)
 
 		# index should be applied or dropped irrespective of type change
-		if (current_def['index'] and not self.set_index):
+		if (current_def['index'] and not self.set_index) and column_type not in ('text', 'longtext'):
 			self.table.drop_index.append(self)
 
 		elif (not current_def['index'] and self.set_index) and not (column_type in ('text', 'longtext')):

frappe/tests/test_db_update.py

@@ -80,6 +80,12 @@ class TestDBUpdate(unittest.TestCase):
 		self.assertFalse(restrict_ip_in_table.index)
 		self.assertTrue(restrict_ip_in_table.unique)
 
+		# explicitly make a text index
+		frappe.db.add_index(doctype, ["email_signature(200)"])
+		frappe.db.updatedb(doctype)
+		email_sig_column = get_table_column("User", "email_signature")
+		self.assertEqual(email_sig_column.index, 1)
+
 def get_fieldtype_from_def(field_def):
 	fieldtuple = frappe.db.type_map.get(field_def.fieldtype, ('', 0))
 	fieldtype = fieldtuple[0]
@@ -119,4 +125,4 @@ def get_other_fields_meta(meta):
 
 def get_table_column(doctype, fieldname):
 	table_columns = frappe.db.get_table_columns_description('tab{}'.format(doctype))
-	return find(table_columns, lambda d: d.get('name') == fieldname)
+	return find(table_columns, lambda d: d.get('name') == fieldname)