Fix (dev): return empty list for non-positive search limit (#12703)

src/documents/search/_backend.py

@@ -681,6 +681,8 @@ class TantivyBackend:
 
         searcher = self._index.searcher()
         effective_limit = limit if limit is not None else searcher.num_docs
+        if effective_limit <= 0:
+            return []
 
         if sort_field and sort_field in self.SORT_FIELD_MAP:
             mapped_field = self.SORT_FIELD_MAP[sort_field]

src/documents/tests/search/test_backend.py

@@ -40,6 +40,10 @@ class TestWriteBatch:
 class TestSearch:
     """Test search query parsing and matching via search_ids."""
 
+    def test_empty_index_returns_no_ids(self, backend: TantivyBackend) -> None:
+        """Empty indexes must not pass a zero limit to Tantivy."""
+        assert backend.search_ids("missing", user=None) == []
+
     def test_text_mode_limits_default_search_to_title_and_content(
         self,
         backend: TantivyBackend,