Installing `jaxtyping` makes Pytest slow(er)

[thejcannon]

👋

On my machine:

$ time python -c 'import jaxtyping'
python -c 'import jaxtyping'  3.66s user 4.95s system 312% cpu 2.757 total

so, because jaxtyping has the pytest entry point, pytest will load jaxtyping._pytest_plugin which loads jaxtyping which takes 2.75s.

Would you consider putting the pytest-related code under a different tree?

[patrick-kidger]

Hey there! Hmm, I don't think I understand this one. Doing just python -c 'import jaxtyping' shouldn't load pytest at all. In fact with this not even jaxtyping._pytest_plugin is loaded -- this entry point is accessed only by pytest itself.

[thejcannon]

Right, the two things I was trying to show are:

• Importing jaxtyping takes 2.75s
• Because jaxtyping has a pytest hook, pytest loads it, and because the hook points to jaxtyping._pytest_plugin, which is underneath jaxtyping, then jaxtyping/__init__.py is loaded (and he's the slow boy)

So, any pytest invocation is now 2.75s slower.

[patrick-kidger]

Ah, hmm. Perhaps it'll be the way that jaxtyping checks if JAX/Equinox are available. I'm speculating here as jaxtyping itself is tiny.

If you can, try benchmarking what happens when {jax, equinox} x {are, aren't} available to be imported and see how that changes things? Maybe we can optimise that somehow.

(FWIW I frequently use jaxtyping + pytest and don't see this kind of multisecond lag, but maybe there's some kind of machine-to-machine variation there.)