Bah, deal with ASNs

src/documents/bulk_edit.py

@@ -651,11 +651,19 @@ def merge_as_versions(
             or 0
         )
 
+        # A version gives up its ASN
+        source_asns = [
+            documents_by_id[source_id].archive_serial_number
+            for source_id in source_ids
+            if documents_by_id[source_id].archive_serial_number is not None
+        ]
+
         for source_id in source_ids:
             source_document = documents_by_id[source_id]
             next_version_index += 1
             source_document.root_document = root_document
             source_document.version_index = next_version_index
+            source_document.archive_serial_number = None
             update_fields = [
                 "root_document",
                 "version_index",
@@ -664,11 +672,25 @@ def merge_as_versions(
             if version_label is not None:
                 source_document.version_label = version_label
                 update_fields.append("version_label")
-            source_document.archive_serial_number = None
             source_document.save(update_fields=update_fields)
 
+        root_update_fields = ["modified"]
+        if source_asns and root_document.archive_serial_number is None:
+            # If a version had one, hand the ASN over, the same as merge() does
+            root_document.archive_serial_number = source_asns.pop(0)
+            root_update_fields.append("archive_serial_number")
+            logger.info(
+                f"Document {root_document.id} took archive serial number "
+                f"{root_document.archive_serial_number} from a document merged into it",
+            )
+        if source_asns:
+            logger.warning(
+                f"Archive serial number(s) {source_asns} were removed by merging "
+                f"those documents as versions of document {root_document.id}",
+            )
+
         root_document.modified = timezone.now()
-        root_document.save(update_fields=["modified"])
+        root_document.save(update_fields=root_update_fields)
 
     for source_id in source_ids:
         remove_document_from_index.apply_async(args=[source_id])

src/documents/tests/test_merge_documents_as_versions.py

@@ -223,6 +223,8 @@ class TestMergeDocumentsAsVersions(TestCase):
         self.assertEqual(source1.version_index, 4)
         self.assertIsNone(source1.archive_serial_number)
         self.assertIsNone(source2.archive_serial_number)
+        # The root had no ASN of its own, so it takes the first one
+        self.assertEqual(root.archive_serial_number, 1)
         self.assertGreater(root.modified, original_modified)
         self.assertEqual(existing_version.root_document_id, root.id)
 
@@ -238,6 +240,52 @@ class TestMergeDocumentsAsVersions(TestCase):
             [source1.id, source2.id],
         )
 
+    @mock.patch("documents.bulk_edit.DocumentsStatusManager")
+    @mock.patch("documents.bulk_edit.bulk_update_documents.apply_async")
+    @mock.patch("documents.bulk_edit.remove_document_from_index.apply_async")
+    def test_root_keeps_its_own_archive_serial_number(self, *_mocks) -> None:
+        root = Document.objects.create(
+            checksum="A",
+            title="Root",
+            archive_serial_number=1,
+        )
+        source = Document.objects.create(
+            checksum="B",
+            title="Source",
+            archive_serial_number=2,
+        )
+
+        with self.assertLogs("paperless.bulk_edit", level="WARNING") as logs:
+            merge_as_versions([root.id, source.id], root_document_id=root.id)
+
+        root.refresh_from_db()
+        source.refresh_from_db()
+        self.assertEqual(root.archive_serial_number, 1)
+        self.assertIsNone(source.archive_serial_number)
+        # Dropping an ASN is not silent
+        self.assertIn("[2]", logs.output[0])
+
+    @mock.patch("documents.bulk_edit.DocumentsStatusManager")
+    @mock.patch("documents.bulk_edit.bulk_update_documents.apply_async")
+    @mock.patch("documents.bulk_edit.remove_document_from_index.apply_async")
+    def test_root_without_asn_takes_the_source_archive_serial_number(
+        self,
+        *_mocks,
+    ) -> None:
+        root = Document.objects.create(checksum="A", title="Root")
+        source = Document.objects.create(
+            checksum="B",
+            title="Source",
+            archive_serial_number=7,
+        )
+
+        merge_as_versions([root.id, source.id], root_document_id=root.id)
+
+        root.refresh_from_db()
+        source.refresh_from_db()
+        self.assertEqual(root.archive_serial_number, 7)
+        self.assertIsNone(source.archive_serial_number)
+
     @mock.patch("documents.bulk_edit.DocumentsStatusManager")
     @mock.patch("documents.bulk_edit.bulk_update_documents.apply_async")
     @mock.patch("documents.bulk_edit.remove_document_from_index.apply_async")