From b3bc5d2ce6792dbc536ec256de4fa6a59e9593b8 Mon Sep 17 00:00:00 2001
From: shamoon <4887959+shamoon@users.noreply.github.com>
Date: Tue, 25 Feb 2025 23:58:28 -0800
Subject: [PATCH] Cleanup custom fields from saved views on deletion

---
 src/documents/signals/handlers.py         | 28 ++++++++++++++++++
 src/documents/tests/test_api_documents.py | 36 +++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/src/documents/signals/handlers.py b/src/documents/signals/handlers.py
index 4345e04d5..b3f029da7 100644
--- a/src/documents/signals/handlers.py
+++ b/src/documents/signals/handlers.py
@@ -36,6 +36,7 @@ from documents.models import Document
 from documents.models import DocumentType
 from documents.models import MatchingModel
 from documents.models import PaperlessTask
+from documents.models import SavedView
 from documents.models import Tag
 from documents.models import Workflow
 from documents.models import WorkflowAction
@@ -549,6 +550,33 @@ def check_paths_and_prune_custom_fields(sender, instance: CustomField, **kwargs)
             update_filename_and_move_files(sender, cf_instance)
 
 
+@receiver(models.signals.post_delete, sender=CustomField)
+def cleanup_custom_field_deletion(sender, instance: CustomField, **kwargs):
+    """
+    When a custom field is deleted, ensure no saved views reference it.
+    """
+    field_identifier = SavedView.DisplayFields.CUSTOM_FIELD % instance.pk
+    # remove field from display_fields of all saved views
+    for view in SavedView.objects.filter(display_fields__isnull=False).distinct():
+        if field_identifier in view.display_fields:
+            logger.debug(
+                f"Removing custom field {instance} from view {view}",
+            )
+            view.display_fields.remove(field_identifier)
+            view.save()
+
+    # remove from sort_field of all saved views
+    views_with_sort_updated = SavedView.objects.filter(
+        sort_field=field_identifier,
+    ).update(
+        sort_field=SavedView.DisplayFields.CREATED,
+    )
+    if views_with_sort_updated > 0:
+        logger.debug(
+            f"Removing custom field {instance} from sort field of {views_with_sort_updated} views",
+        )
+
+
 def add_to_index(sender, document, **kwargs):
     from documents import index
 
diff --git a/src/documents/tests/test_api_documents.py b/src/documents/tests/test_api_documents.py
index 28261b392..cd923b281 100644
--- a/src/documents/tests/test_api_documents.py
+++ b/src/documents/tests/test_api_documents.py
@@ -1925,6 +1925,42 @@ class TestDocumentApi(DirectoriesMixin, DocumentConsumeDelayMixin, APITestCase):
         )
         self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
 
+    def test_saved_view_cleanup_after_custom_field_deletion(self):
+        """
+        GIVEN:
+            - Saved view with custom field in display fields and as sort field
+        WHEN:
+            - Custom field is deleted
+        THEN:
+            - Custom field is removed from display fields and sort field
+        """
+        custom_field = CustomField.objects.create(
+            name="stringfield",
+            data_type=CustomField.FieldDataType.STRING,
+        )
+
+        view = SavedView.objects.create(
+            owner=self.user,
+            name="test",
+            sort_field=SavedView.DisplayFields.CUSTOM_FIELD % custom_field.id,
+            show_on_dashboard=True,
+            show_in_sidebar=True,
+            display_fields=[
+                SavedView.DisplayFields.TITLE,
+                SavedView.DisplayFields.CREATED,
+                SavedView.DisplayFields.CUSTOM_FIELD % custom_field.id,
+            ],
+        )
+
+        custom_field.delete()
+
+        view.refresh_from_db()
+        self.assertEqual(view.sort_field, SavedView.DisplayFields.CREATED)
+        self.assertEqual(
+            view.display_fields,
+            [str(SavedView.DisplayFields.TITLE), str(SavedView.DisplayFields.CREATED)],
+        )
+
     def test_get_logs(self):
         log_data = "test\ntest2\n"
         with (Path(settings.LOGGING_DIR) / "mail.log").open("w") as f: