How to mitigate Model observation with save points is unsupported and will result in unexpected beauvoir.

[ranzbak]

In my application, I noticed the warning:

Model observation with save points is unsupported and will result in unexpected beauvoir.

it originates from : djangochannelsrestframework/observer/model_observer.py:121

I looked around on Google, and in this project but there is no documentation on what causes this Warning.
My knowledge about Django is not sufficient enough to deduce the problem from the source code at this time.

I know it results from transactions Django sets up in the database, but I have no clue about what causes those transactions to be problematic.

Please advice.

[hishnash]

Hi,

this some from here:

https://github.com/LostMoa/djangochannelsrestframework/blob/fbbdfcab72fe7d9a0954f9c3dce0094a702d7e01/djangochannelsrestframework/observer/model_observer.py#L105-L117

The reason the warning is raised is due to how I detect model changes for subscriptions. Im using the Django on_commit hook to defer sending the update over the channel group until after the commit has taken place. (otherwise we would send changes that might later be rolled back).

but the change on_commit hook as far as im aware is fired when nested transactional blocks complete (aka save points) this means that Django sends the on_commit event but the real transition has not completed, so the change could still be rolled back.

I do want to do further investigation into Django code base to figure out if there is a way to filter out these on-commit calls to that I can correctly track changes from save-points (eg if a save point is reverted ignore its changes but keep others).

[SETTER2000]

Thank you for the clarification. Has anything been clarified? How to deal with this is not clear?