Ignore null changeset on creation and deletion

auditlog/diff.py

@@ -2,7 +2,7 @@
 from django.core.exceptions import ObjectDoesNotExist
 from django.db.models import Model, NOT_PROVIDED, DateTimeField
 from django.utils import timezone
-from django.utils.encoding import smart_text
+from django.utils.encoding import smart_str
 
 
 def track_field(field):
@@ -17,12 +17,16 @@ def track_field(field):
     :rtype: bool
     """
     from auditlog.models import LogEntry
+
     # Do not track many to many relations
     if field.many_to_many:
         return False
 
     # Do not track relations to LogEntry
-    if getattr(field, 'remote_field', None) is not None and field.remote_field.model == LogEntry:
+    if (
+        getattr(field, "remote_field", None) is not None
+        and field.remote_field.model == LogEntry
+    ):
         return False
 
     return True
@@ -65,7 +69,7 @@ def get_field_value(obj, field):
             value = field.default if field.default is not NOT_PROVIDED else None
     else:
         try:
-            value = smart_text(getattr(obj, field.name, None))
+            value = smart_str(getattr(obj, field.name, None))
         except ObjectDoesNotExist:
             value = field.default if field.default is not NOT_PROVIDED else None
 
@@ -108,24 +112,34 @@ def model_instance_diff(old, new):
         model_fields = None
 
     # Check if fields must be filtered
-    if model_fields and (model_fields['include_fields'] or model_fields['exclude_fields']) and fields:
+    if (
+        model_fields
+        and (model_fields["include_fields"] or model_fields["exclude_fields"])
+        and fields
+    ):
         filtered_fields = []
-        if model_fields['include_fields']:
-            filtered_fields = [field for field in fields
-                               if field.name in model_fields['include_fields']]
+        if model_fields["include_fields"]:
+            filtered_fields = [
+                field
+                for field in fields
+                if field.name in model_fields["include_fields"]
+            ]
         else:
             filtered_fields = fields
-        if model_fields['exclude_fields']:
-            filtered_fields = [field for field in filtered_fields
-                               if field.name not in model_fields['exclude_fields']]
+        if model_fields["exclude_fields"]:
+            filtered_fields = [
+                field
+                for field in filtered_fields
+                if field.name not in model_fields["exclude_fields"]
+            ]
         fields = filtered_fields
 
     for field in fields:
         old_value = get_field_value(old, field)
         new_value = get_field_value(new, field)
 
         if old_value != new_value:
-            diff[field.name] = (smart_text(old_value), smart_text(new_value))
+            diff[field.name] = (smart_str(old_value), smart_str(new_value))
 
     if len(diff) == 0:
         diff = None

auditlog/receivers.py

@@ -13,11 +13,13 @@ def log_create(sender, instance, created, **kwargs):
     if created:
         changes = model_instance_diff(None, instance)
 
-        log_entry = LogEntry.objects.log_create(
-            instance,
-            action=LogEntry.Action.CREATE,
-            changes=json.dumps(changes),
-        )
+        # Log an entry only if there are changes
+        if changes:
+            log_entry = LogEntry.objects.log_create(
+                instance,
+                action=LogEntry.Action.CREATE,
+                changes=json.dumps(changes),
+            )
 
 
 def log_update(sender, instance, **kwargs):
@@ -54,8 +56,10 @@ def log_delete(sender, instance, **kwargs):
     if instance.pk is not None:
         changes = model_instance_diff(instance, None)
 
-        log_entry = LogEntry.objects.log_create(
-            instance,
-            action=LogEntry.Action.DELETE,
-            changes=json.dumps(changes),
-        )
+        # Log an entry only if there are changes
+        if changes:
+            log_entry = LogEntry.objects.log_create(
+                instance,
+                action=LogEntry.Action.DELETE,
+                changes=json.dumps(changes),
+            )

auditlog_tests/models.py

@@ -85,7 +85,7 @@ class SimpleIncludeModel(models.Model):
     A simple model used for register's include_fields kwarg
     """
 
-    label = models.CharField(max_length=100)
+    label = models.CharField(null=True, max_length=100)
     text = models.TextField(blank=True)
 
     history = AuditlogHistoryField()

auditlog_tests/tests.py

@@ -200,6 +200,20 @@ def test_register_include_fields(self):
         sim.save()
         self.assertTrue(sim.history.count() == 2, msg="There are two log entries")
 
+        # Create with text, ignore
+        sim = SimpleIncludeModel(text="Looong text")
+        sim.save()
+        self.assertTrue(sim.history.count() == 0, msg="There are no log entries")
+
+        # Delete, ignore
+        self.assertTrue(
+            LogEntry.objects.count() == 2, msg="There are two log entries total"
+        )
+        sim.delete()
+        self.assertTrue(
+            LogEntry.objects.count() == 2, msg="No log entry added after delete"
+        )
+
 
 class SimpeExcludeModelTest(TestCase):
     """Log only changes that are not in exclude_fields"""