Cleanup

src/registrar/models/domain.py

@@ -830,15 +830,68 @@ class Domain(TimeStampedModel, DomainHelper):
             # TODO-error handling better here?
 
     def try_set_singleton_contact(self, contact: PublicContact, expected_type: str):  # noqa
-        """Runs the _set_singleton_contact function, while catching an IntegrityError
-        from the DB and handling it appropriately"""
+        """
+        Attempts to set a singleton contact for a domain, 
+        handling potential IntegrityErrors due to duplicate entries.
+
+        This function wraps the `_set_singleton_contact` method, 
+        which is intended to assign a unique contact of a specified type to a domain.
+
+        If a duplicate is detected, all duplicate entries are deleted before retrying the operation.
+        
+        Args:
+            contact (PublicContact): The contact instance to set as a singleton.
+            expected_type (str): The expected type of the contact (e.g., 'technical', 'administrative').
+
+        Raises:
+            IntegrityError: Re-raises the IntegrityError if an unexpected number of duplicates are found,
+            or on the rerun of _set_singleton_contact.
+        """
         try:
             self._set_singleton_contact(contact=contact, expectedType=expected_type)
         except IntegrityError as err:
-            # If this error occurs, it indicates that our DB tried to create 
-            # a duplicate PublicContact
+            # If this error occurs, it indicates that our DB tried to create a duplicate PublicContact
             logger.error(f"A contact with this registry ID already exists. Error: {err}")
 
+            # Delete the duplicates and try again.
+            duplicates = PublicContact.objects.filter(
+                registry_id=contact.registry_id,
+                contact_type=contact.contact_type,
+                domain=self,
+            )
+
+            # If we find duplicates, log it and delete the newest one.
+            if duplicates.count() <= 1:
+                # Something weird happened - we got an integrity error with one or fewer records
+                # which should not be possible.
+                logger.error(
+                    "try_set_singleton_contact() -> "
+                    f"An IntegrityError was raised but {duplicates.count()} entries exist"
+                )
+                # Raise the error. This is a case in which it is appropriate to do so.
+                raise err
+            else:
+                logger.warning("try_set_singleton_contact() -> Duplicate contacts found. Deleting duplicate.")
+                self._delete_duplicates(duplicates)
+            
+            # Try to set the contact again. If we get an error at this point, then
+            # this indicates a very bad data issue in the DB (duplicate registry_ids on other domains).
+            # This requires patching the DB and epp with a script due to the epp <---> DB link.
+            # Trying to fix that here will just result in corrupt EPP records.
+            self._set_singleton_contact(contact=contact, expectedType=expected_type)
+
+    def _delete_duplicates(self, duplicates):
+        """Given a list of duplicates, delete all but the oldest one."""
+
+        # Q: Should we be deleting the newest or the oldest? Does it even matter?
+        oldest_duplicate = duplicates.order_by('created_at').first()
+
+        # Exclude the oldest entry
+        duplicates_to_delete = duplicates.exclude(id=oldest_duplicate.id)
+
+        # Delete all duplicates
+        duplicates_to_delete.delete()
+
     def _set_singleton_contact(self, contact: PublicContact, expectedType: str):  # noqa
         """Sets the contacts by adding them to the registry as new contacts,
         updates the contact if it is already in epp,
@@ -1969,9 +2022,7 @@ class Domain(TimeStampedModel, DomainHelper):
         # If we find duplicates, log it and delete the newest one.
         if db_contact.count() > 1:
             logger.warning("_get_or_create_public_contact() -> Duplicate contacts found. Deleting duplicate.")
-            # Q: Should we be deleting the newest or the oldest? Does it even matter?
-            newest_duplicate = db_contact.order_by('-created_at').first()
-            newest_duplicate.delete()
+            self._delete_duplicates(db_contact)
 
         # Save to DB if it doesn't exist already.
         if db_contact.count() == 0: