Fix Handling of shell.should_run_async

[afshin]

Fixes #540

[blink1073]

Thanks!

[jccurtis]

Yes thank you! Is there a planned release with this fix?

[blink1073]

@meeseeksdev please backport to 5.5.x

[blink1073]

Done! https://pypi.org/project/ipykernel/5.5.1/

[blink1073]

I deleted https://pypi.org/project/ipykernel/5.5.1 because we would have to upgrade our ipython dependency to 7.17, which doesn't make sense in a patch release. cf #607. This will have to wait for the next minor or major release, whichever comes first.

[Carreau]

Noooooooooo.

That reintroduce the exact bug the change of API was meant to prevent. We have transformers that are stateful; they destroy data if called twice.

self.shell.transform_cell(code) should not be called twice in an execution loop. The warning is there for a reason.

[afshin]

That reintroduce the exact bug the change of API was meant to prevent. We have transformers that are stateful; they destroy data if called twice.

self.shell.transform_cell(code) should not be called twice in an execution loop. The warning is there for a reason.

Ah, did we miss passing transformed_cell and preprocessing_exc_tuple here and perhaps here?