Make skip_history_when_saving work when creating a new object (#1262)

* Made skip_history_when_saving work when creating

...a model object - not just when updating an object.

Also improved the docs on saving without creating historical records,
and fixed an unrelated `PollWithManyToMany` instance being used in the
assertions in the existing test for `skip_history_when_saving`.

* Apply suggestions from code review

Co-authored-by: Tim Schilling <[email protected]>

* More docs suggestions from code review

---------

Co-authored-by: Tim Schilling <[email protected]>

Author: ddabble

CHANGES.rst

@@ -4,6 +4,8 @@ Changes
 Unreleased
 ----------
 
+- Made ``skip_history_when_saving`` work when creating an object - not just when
+  updating an object (gh-1262)
 
 3.7.0 (2024-05-29)
 ------------------

docs/querying_history.rst

@@ -175,30 +175,50 @@ model history.
     <Poll: Poll object as of 2010-10-25 18:04:13.814128>
 
 
-Save without a historical record
---------------------------------
+Save without creating historical records
+----------------------------------------
 
-If you want to save a model without a historical record, you can use the following:
+If you want to save model objects without triggering the creation of any historical
+records, you can do the following:
 
 .. code-block:: python
 
-    class Poll(models.Model):
-        question = models.CharField(max_length=200)
-        history = HistoricalRecords()
+    poll.skip_history_when_saving = True
+    poll.save()
+    # We recommend deleting the attribute afterward
+    del poll.skip_history_when_saving
+
+This also works when creating an object, but only when calling ``save()``:
+
+.. code-block:: python
+
+    # Note that `Poll.objects.create()` is not called
+    poll = Poll(question="Why?")
+    poll.skip_history_when_saving = True
+    poll.save()
+    del poll.skip_history_when_saving
 
-        def save_without_historical_record(self, *args, **kwargs):
-            self.skip_history_when_saving = True
-            try:
-                ret = self.save(*args, **kwargs)
-            finally:
-                del self.skip_history_when_saving
-            return ret
+.. note::
+    Historical records will always be created when calling the ``create()`` manager method.
 
+Alternatively, call the ``save_without_historical_record()`` method on each object
+instead of ``save()``.
+This method is automatically added to a model when registering it for history-tracking
+(i.e. defining a ``HistoricalRecords``  manager field on the model),
+and it looks like this:
+
+.. code-block:: python
 
-    poll = Poll(question='something')
-    poll.save_without_historical_record()
+    def save_without_historical_record(self, *args, **kwargs):
+        self.skip_history_when_saving = True
+        try:
+            ret = self.save(*args, **kwargs)
+        finally:
+            del self.skip_history_when_saving
+        return ret
 
-Or disable history records for all models by putting following lines in your ``settings.py`` file:
+Or disable the creation of historical records for *all* models
+by adding the following line to your settings:
 
 .. code-block:: python
 

simple_history/models.py

@@ -180,9 +180,9 @@ def contribute_to_class(self, cls, name):
     def add_extra_methods(self, cls):
         def save_without_historical_record(self, *args, **kwargs):
             """
-            Save model without saving a historical record
+            Save the model instance without creating a historical record.
 
-            Make sure you know what you're doing before you use this method.
+            Make sure you know what you're doing before using this method.
             """
             self.skip_history_when_saving = True
             try:
@@ -651,8 +651,9 @@ def get_meta_options(self, model):
     def post_save(self, instance, created, using=None, **kwargs):
         if not getattr(settings, "SIMPLE_HISTORY_ENABLED", True):
             return
-        if not created and hasattr(instance, "skip_history_when_saving"):
+        if hasattr(instance, "skip_history_when_saving"):
             return
+
         if not kwargs.get("raw", False):
             self.create_historical_record(instance, created and "+" or "~", using=using)
 

simple_history/tests/tests/test_models.py

@@ -2424,21 +2424,21 @@ def test_m2m_relation(self):
         self.assertEqual(self.poll.history.all()[0].places.count(), 0)
         self.assertEqual(poll_2.history.all()[0].places.count(), 2)
 
-    def test_skip_history(self):
+    def test_skip_history_when_updating_an_object(self):
         skip_poll = PollWithManyToMany.objects.create(
             question="skip history?", pub_date=today
         )
-        self.assertEqual(self.poll.history.all().count(), 1)
-        self.assertEqual(self.poll.history.all()[0].places.count(), 0)
+        self.assertEqual(skip_poll.history.all().count(), 1)
+        self.assertEqual(skip_poll.history.all()[0].places.count(), 0)
 
         skip_poll.skip_history_when_saving = True
 
         skip_poll.question = "huh?"
         skip_poll.save()
         skip_poll.places.add(self.place)
 
-        self.assertEqual(self.poll.history.all().count(), 1)
-        self.assertEqual(self.poll.history.all()[0].places.count(), 0)
+        self.assertEqual(skip_poll.history.all().count(), 1)
+        self.assertEqual(skip_poll.history.all()[0].places.count(), 0)
 
         del skip_poll.skip_history_when_saving
         place_2 = Place.objects.create(name="Place 2")
@@ -2448,6 +2448,18 @@ def test_skip_history(self):
         self.assertEqual(skip_poll.history.all().count(), 2)
         self.assertEqual(skip_poll.history.all()[0].places.count(), 2)
 
+    def test_skip_history_when_creating_an_object(self):
+        initial_poll_count = PollWithManyToMany.objects.count()
+
+        skip_poll = PollWithManyToMany(question="skip history?", pub_date=today)
+        skip_poll.skip_history_when_saving = True
+        skip_poll.save()
+        skip_poll.places.add(self.place)
+
+        self.assertEqual(skip_poll.history.count(), 0)
+        self.assertEqual(PollWithManyToMany.objects.count(), initial_poll_count + 1)
+        self.assertEqual(skip_poll.places.count(), 1)
+
     @override_settings(SIMPLE_HISTORY_ENABLED=False)
     def test_saving_with_disabled_history_doesnt_create_records(self):
         # 1 from `setUp()`