feat: delegate sorting to Tantivy and use page-only highlights in viewset

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/documents/tests/test_api_search.py

@@ -1503,6 +1503,89 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             [d2.id, d1.id, d3.id],
         )
 
+    def test_search_with_tantivy_native_sort(self) -> None:
+        """When ordering by a Tantivy-sortable field, results must be correctly sorted."""
+        backend = get_backend()
+        for i, asn in enumerate([30, 10, 20]):
+            doc = Document.objects.create(
+                title=f"sortable doc {i}",
+                content="searchable content",
+                checksum=f"TNS{i}",
+                archive_serial_number=asn,
+            )
+            backend.add_or_update(doc)
+
+        response = self.client.get(
+            "/api/documents/?query=searchable&ordering=archive_serial_number",
+        )
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        asns = [doc["archive_serial_number"] for doc in response.data["results"]]
+        self.assertEqual(asns, [10, 20, 30])
+
+        response = self.client.get(
+            "/api/documents/?query=searchable&ordering=-archive_serial_number",
+        )
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        asns = [doc["archive_serial_number"] for doc in response.data["results"]]
+        self.assertEqual(asns, [30, 20, 10])
+
+    def test_search_page_2_returns_correct_slice(self) -> None:
+        """Page 2 must return the second slice, not overlap with page 1."""
+        backend = get_backend()
+        for i in range(10):
+            doc = Document.objects.create(
+                title=f"doc {i}",
+                content="paginated content",
+                checksum=f"PG2{i}",
+                archive_serial_number=i + 1,
+            )
+            backend.add_or_update(doc)
+
+        response = self.client.get(
+            "/api/documents/?query=paginated&ordering=archive_serial_number&page=1&page_size=3",
+        )
+        page1_ids = [r["id"] for r in response.data["results"]]
+        self.assertEqual(len(page1_ids), 3)
+
+        response = self.client.get(
+            "/api/documents/?query=paginated&ordering=archive_serial_number&page=2&page_size=3",
+        )
+        page2_ids = [r["id"] for r in response.data["results"]]
+        self.assertEqual(len(page2_ids), 3)
+
+        # No overlap between pages
+        self.assertEqual(set(page1_ids) & set(page2_ids), set())
+        # Page 2 ASNs are higher than page 1
+        page1_asns = [
+            Document.objects.get(pk=pk).archive_serial_number for pk in page1_ids
+        ]
+        page2_asns = [
+            Document.objects.get(pk=pk).archive_serial_number for pk in page2_ids
+        ]
+        self.assertTrue(max(page1_asns) < min(page2_asns))
+
+    def test_search_all_field_contains_all_ids_when_paginated(self) -> None:
+        """The 'all' field must contain every matching ID, even when paginated."""
+        backend = get_backend()
+        doc_ids = []
+        for i in range(10):
+            doc = Document.objects.create(
+                title=f"all field doc {i}",
+                content="allfield content",
+                checksum=f"AF{i}",
+            )
+            backend.add_or_update(doc)
+            doc_ids.append(doc.pk)
+
+        response = self.client.get(
+            "/api/documents/?query=allfield&page=1&page_size=3",
+            headers={"Accept": "application/json; version=9"},
+        )
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data["results"]), 3)
+        # "all" must contain ALL 10 matching IDs
+        self.assertCountEqual(response.data["all"], doc_ids)
+
     @mock.patch("documents.bulk_edit.bulk_update_documents")
     def test_global_search(self, m) -> None:
         """