From 32078bea377808ee22ffddaba97f2dae5048efd5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Aleh=20Ryma=C5=A1e=C5=ADski?= <alieh.rymasheuski@gmail.com>
Date: Sat, 2 Dec 2023 22:08:20 -0100
Subject: [PATCH] Handle ObjectDoesNotExist in evaluation of repr

---
 CHANGELOG.md             |  4 ++++
 auditlog/models.py       | 14 ++++++++++++--
 auditlog_tests/models.py |  3 +++
 auditlog_tests/tests.py  | 21 ++++++++++++++++++++-
 4 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2a501a09..fc9acbca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@
 - Python: Confirm Python 3.12 support ([#572](https://github.com/jazzband/django-auditlog/pull/572))
 - feat: `thread.local` replaced with `ContextVar` to improve context managers in Django 4.2+
 
+#### Fixes
+
+- fix: Handle `ObjectDoesNotExist` in evaluation of `object_repr` ([#592](https://github.com/jazzband/django-auditlog/pull/592))
+
 ## 3.0.0-beta.2 (2023-10-05)
 
 #### Breaking Changes
diff --git a/auditlog/models.py b/auditlog/models.py
index 81198379..e0c637db 100644
--- a/auditlog/models.py
+++ b/auditlog/models.py
@@ -25,6 +25,8 @@
 
 from auditlog.diff import mask_str
 
+DEFAULT_OBJECT_REPR = "<error forming object repr>"
+
 
 class LogEntryManager(models.Manager):
     """
@@ -54,7 +56,11 @@ def log_create(self, instance, force_log: bool = False, **kwargs):
                 "content_type", ContentType.objects.get_for_model(instance)
             )
             kwargs.setdefault("object_pk", pk)
-            kwargs.setdefault("object_repr", smart_str(instance))
+            try:
+                object_repr = smart_str(instance)
+            except ObjectDoesNotExist:
+                object_repr = DEFAULT_OBJECT_REPR
+            kwargs.setdefault("object_repr", object_repr)
             kwargs.setdefault(
                 "serialized_data", self._get_serialized_data_or_none(instance)
             )
@@ -96,7 +102,11 @@ def log_m2m_changes(
                 "content_type", ContentType.objects.get_for_model(instance)
             )
             kwargs.setdefault("object_pk", pk)
-            kwargs.setdefault("object_repr", smart_str(instance))
+            try:
+                object_repr = smart_str(instance)
+            except ObjectDoesNotExist:
+                object_repr = DEFAULT_OBJECT_REPR
+            kwargs.setdefault("object_repr", object_repr)
             kwargs.setdefault("action", LogEntry.Action.UPDATE)
 
             if isinstance(pk, int):
diff --git a/auditlog_tests/models.py b/auditlog_tests/models.py
index 04736a05..1e16f933 100644
--- a/auditlog_tests/models.py
+++ b/auditlog_tests/models.py
@@ -86,6 +86,9 @@ class RelatedModel(RelatedModelParent):
 
     history = AuditlogHistoryField(delete_related=True)
 
+    def __str__(self):
+        return f"RelatedModel #{self.pk} -> {self.related.id}"
+
 
 class ManyRelatedModel(models.Model):
     """
diff --git a/auditlog_tests/tests.py b/auditlog_tests/tests.py
index 8a84385c..79a65869 100644
--- a/auditlog_tests/tests.py
+++ b/auditlog_tests/tests.py
@@ -29,7 +29,7 @@
 from auditlog.context import disable_auditlog, set_actor
 from auditlog.diff import model_instance_diff
 from auditlog.middleware import AuditlogMiddleware
-from auditlog.models import LogEntry
+from auditlog.models import DEFAULT_OBJECT_REPR, LogEntry
 from auditlog.registry import AuditlogModelRegistry, AuditLogRegistrationError, auditlog
 from auditlog.signals import post_log, pre_log
 from auditlog_tests.fixtures.custom_get_cid import get_cid as custom_get_cid
@@ -1860,6 +1860,25 @@ def test_diff_models_with_related_fields(self):
         model_instance_diff(simple2, simple1)
         model_instance_diff(simple1, simple2)
 
+    def test_object_repr_related_deleted(self):
+        """No error is raised when __str__() loads a related object that has been deleted."""
+        simple = SimpleModel()
+        simple.save()
+        related = RelatedModel(related=simple, one_to_one=simple)
+        related.save()
+        related_id = related.id
+
+        related.refresh_from_db()
+        simple.delete()
+        related.delete()
+
+        log_entry = (
+            LogEntry.objects.get_for_model(RelatedModel)
+            .filter(object_id=related_id)
+            .get(action=LogEntry.Action.DELETE)
+        )
+        self.assertEqual(log_entry.object_repr, DEFAULT_OBJECT_REPR)
+
     def test_when_field_doesnt_exist(self):
         """No error is raised and the default is returned."""
         first = SimpleModel(boolean=True)