Performance: avoid unnecessary filename operations on bulk custom field updates (#11558)

src/documents/tests/test_file_handling.py

@@ -16,6 +16,7 @@ from django.utils import timezone
 from documents.file_handling import create_source_path_directory
 from documents.file_handling import delete_empty_directories
 from documents.file_handling import generate_filename
+from documents.file_handling import generate_unique_filename
 from documents.models import Correspondent
 from documents.models import CustomField
 from documents.models import CustomFieldInstance
@@ -1632,6 +1633,73 @@ class TestFilenameGeneration(DirectoriesMixin, TestCase):
             )
 
 
+class TestCustomFieldFilenameUpdates(
+    DirectoriesMixin,
+    FileSystemAssertsMixin,
+    TestCase,
+):
+    def setUp(self):
+        self.cf = CustomField.objects.create(
+            name="flavor",
+            data_type=CustomField.FieldDataType.STRING,
+        )
+        self.doc = Document.objects.create(
+            title="document",
+            mime_type="application/pdf",
+            checksum="abc123",
+        )
+        self.cfi = CustomFieldInstance.objects.create(
+            field=self.cf,
+            document=self.doc,
+            value_text="initial",
+        )
+        return super().setUp()
+
+    @override_settings(FILENAME_FORMAT=None)
+    def test_custom_field_not_in_template_skips_filename_work(self):
+        storage_path = StoragePath.objects.create(path="{{created}}/{{ title }}")
+        self.doc.storage_path = storage_path
+        self.doc.save()
+        initial_filename = generate_filename(self.doc)
+        Document.objects.filter(pk=self.doc.pk).update(filename=str(initial_filename))
+        self.doc.refresh_from_db()
+        Path(self.doc.source_path).parent.mkdir(parents=True, exist_ok=True)
+        Path(self.doc.source_path).touch()
+
+        with mock.patch("documents.signals.handlers.generate_unique_filename") as m:
+            m.side_effect = generate_unique_filename
+            self.cfi.value_text = "updated"
+            self.cfi.save()
+
+        self.doc.refresh_from_db()
+        self.assertEqual(Path(self.doc.filename), initial_filename)
+        self.assertEqual(m.call_count, 0)
+
+    @override_settings(FILENAME_FORMAT=None)
+    def test_custom_field_in_template_triggers_filename_update(self):
+        storage_path = StoragePath.objects.create(
+            path="{{ custom_fields|get_cf_value('flavor') }}/{{ title }}",
+        )
+        self.doc.storage_path = storage_path
+        self.doc.save()
+        initial_filename = generate_filename(self.doc)
+        Document.objects.filter(pk=self.doc.pk).update(filename=str(initial_filename))
+        self.doc.refresh_from_db()
+        Path(self.doc.source_path).parent.mkdir(parents=True, exist_ok=True)
+        Path(self.doc.source_path).touch()
+
+        with mock.patch("documents.signals.handlers.generate_unique_filename") as m:
+            m.side_effect = generate_unique_filename
+            self.cfi.value_text = "updated"
+            self.cfi.save()
+
+        self.doc.refresh_from_db()
+        expected_filename = Path("updated/document.pdf")
+        self.assertEqual(Path(self.doc.filename), expected_filename)
+        self.assertTrue(Path(self.doc.source_path).is_file())
+        self.assertLessEqual(m.call_count, 1)
+
+
 class TestPathDateLocalization:
     """
     Groups all tests related to the `localize_date` function.