Best way to dynamically disable creation of history records?

[dmchmk]

Problem Statement
For example, I have some kind of blog, where I do track the history of users' comments. And when a user deletes his comment under any blog post I still want to be able to see it, and maybe recover back.

But when I delete that post, I don't need to know anything about any of those comments any more. And I want not only to remove the existing history (it's quite an easy task) but also not to create "-" historical records caused by cascade delete.

Describe the solution you'd like
The most user-friendly way to do this is to use some method like "save_without_historical_record", described is the docs.

Describe alternatives you've considered
As another possibility, maybe you could tell which Signal I need to disconnect before I call Post.object.delete() ? And how to perform it properly. I've tried to find any help reading the library source code, but, seem to be failed:(

[rossmechanic]

Hi @megavenik – I can't think of a way to disconnect the post_delete signal, as there's no easy way to access the HistoricalRecords model instance that has the receiver function in the first place. Doesn't seem like there's an easy way to pick when you want to do this, although the cascade_delete_history does what you want (you just can't choose when to turn it on or off dynamically). Feels like your best bet is to put up a PR that allows you to specify the cascade_delete_history attribute dynamically, similarly to how it's done on skip_history_when_saving. Referencing to the two sections of the code I'm referring to below:

https://github.com/jazzband/django-simple-history/blob/8bcf4c43cae7c5e77b5cc05d3c66fdb7f5136606/simple_history/models.py#L472
https://github.com/jazzband/django-simple-history/blob/8bcf4c43cae7c5e77b5cc05d3c66fdb7f5136606/simple_history/models.py#L466

[jeking3]

I added this to my model base class, it's quite effective:

@contextmanager
def no_history(self):
    """
    Disable history generation for this instance.
    """
    assert not hasattr(  # nosec
        self, "skip_history_when_saving"
    ), "it is not safe to nest no_history contexts"
    self.skip_history_when_saving = True
    try:
        yield
    finally:
        del self.skip_history_when_saving

If this solves your issue, please consider closing it. Thanks.