Improve sync.py typing and utilities performance

[bellini666]

• Make sure sync_to_async/async_to_sync keeps the original function typing signature

• Define iscoroutinefunction/markcoroutinefunction at import time instead of an if/else in runtime.

The current implementation:

In [7]: timeit.timeit(lambda: iscoroutinefunction(some_sync_func), number=10000)
Out[7]: 0.012024379917420447

Versus this PR

In [11]: timeit.timeit(lambda: iscoroutinefunction(some_sync_func), number=10000)
Out[11]: 0.004663120023906231

This is a performance improvement of almost 300%.

[andrewgodwin]

Code changes look reasonable, but you will need to please the mypy in the CI to get this in!

[bellini666]

@andrewgodwin thanks for the review. Just solved all the issues to please mypy :)

[andrewgodwin]

Unfortunately not for 3.9 and below, it looks like - the problem with ParamSpec is it's relatively new, and you'll need a way of keeping things backward-compatible somehow.

I don't care much about 3.7 as it's about to be EOL, but 3.8 and 3.9 do still matter.

(Apologies I can't tell our CI to run for you on every commit!)

[bellini666]

Unfortunately not for 3.9 and below, it looks like - the problem with ParamSpec is it's relatively new, and you'll need a way of keeping things backward-compatible somehow.

I don't care much about 3.7 as it's about to be EOL, but 3.8 and 3.9 do still matter.

Oh, sorry about that. The code at sync.py was already conditionally importing from typing only for 3.10+, but I forgot to do the same when fixing typing on current_thread_executer.py

I only have python 3.11 in my local dev environment, so I'll only know for older versions once the CI gets to run

(Apologies I can't tell our CI to run for you on every commit!)

Np :)

Hopefully everything should be fine now

[andrewgodwin]

Still something awry it looks like. You should be able to run the full set of python versions tests locally with tox if you'd like.

[bellini666]

Still something awry it looks like. You should be able to run the full set of python versions tests locally with tox if you'd like.

@andrewgodwin I was being lazy to install all required python versions =P. Just did that, ran tox and was able to really fix everything now.

Sorry about that!

[andrewgodwin]

Yup, all looks good now! Thanks, I appreciate you taking the time to go through all those revisions!