server/search: fix errors on negative page offsets

server/szurubooru/search/executor.py

@@ -84,6 +84,10 @@ class Executor:
         search_query = self.parser.parse(query_text)
         self.config.on_search_query_parsed(search_query)
 
+        if offset < 0:
+            limit = max(0, limit + offset)
+            offset = 0
+
         disable_eager_loads = False
         for token in search_query.sort_tokens:
             if token.name == 'random':

server/szurubooru/tests/search/configs/test_user_search_config.py

@@ -155,7 +155,8 @@ def test_combining_tokens(
         (0, 1, 2, ['u1']),
         (1, 1, 2, ['u2']),
         (2, 1, 2, []),
-        (-1, 1, 2, ['u1']),
+        (-1, 1, 2, []),
+        (-1, 2, 2, ['u1']),
         (0, 2, 2, ['u1', 'u2']),
         (3, 1, 2, []),
         (0, 0, 2, []),