using async in names is deprecated on python 3.6

[johnnoone]

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[ghost]

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Appreciation of efforts,

clabot

[ewencp]

@johnnoone Good catch, we would like to avoid abusing the keyword if possible. @edenhill I think the main concern here is probably compatibility. Are we comfortable breaking the existing API given how new this is? Or should we make the patch support both async and asynchronous for now, deprecate async, and remove it in a later release?

[edenhill]

This is still a young project so I vote for not being backwards compatible, let's go with asynchronous in the next release.

Is asynchronous user friendly enough, or should it be something easier to spell, like do_async?

[ewencp]

@edenhill Doesn't look like the PEP suggests a specific alternative. Maybe check a couple of other libraries that have async options to see if there is a de facto standard?

[edenhill]

Sort of missed the train with this one, so we'll add asynchronous=bool kwarg but keep the old async=bool one for backwards compatibility (possibly with a warning), e.g. something like:

 def foo (.., asynchronous=False, async=None):
    if async is not None:
         warning('Use asynchronous instead, kthx')
         asynchronous=async
...

[ah-]

I think it's time to implement this now, since async has started to error on Python 3.7 nightly:

E       self.consumer.commit(offsets=offsets_to_commit, async=False)
E                                                           ^
E   SyntaxError: invalid syntax

Renaming async to asynchronous sounds like a decent solution.

[edenhill]

@ah- I think we should provide an "async" alias for <Py3.7 for a while to not break existing applications. What do you think?

We have an upcoming 1.0.0 release bump coming up in a couple of months at which time we can break the API.

[ah-]

Yes, keeping backwards compatibility would be great. Looking at https://github.com/confluentinc/confluent-kafka-python/blob/master/confluent_kafka/src/Consumer.c#L378 it should be as trivial as adding "asynchronous" to the list of kwargs and then having async = PyObject_IsTrue(async_o) || PyObject_IsTrue(asynchronous_o).

We can probably even keep the old async afterwards, as far as I can tell the only thing that breaks is writing async=False, you could still pass kwargs manually setting {'async': True}.
So no breakage required, just an alias so Py 3.7 users can use normal syntax to call.

[lithammer]

Something like this ought to do it (not very pretty though!):

def foo(..., asynchronous=None, **kwargs):
    asynch = asynchronous or kwargs.get('async')

[edenhill]

@Renstrom That will allow any (unknown) kw arg to be set though. Say Hi to Löfling from me :)

A PR is on the way.

[edenhill]

Updated PR in #319