Callbacks with `syncify()` raises an error about pyodide HOT 2 OPEN

Thanks for the bug report @kor0p. It would definitely be helpful to improve the situation here. With handlers, the main question is whether the callee of the handler will want a sync context or an async one. I don't think there is any reasonable way to introspect this. It would be a good idea to add support for something like this in add_event_listener.

There are also more significant issues about the interaction between stack switching and and async contexts which will have to be ironed out. In particular, our event loop should ideally enter execution contexts with stack switching enabled if the runtime supports it. Since our event loop is calling into the function, we know the context is async. Though this could potentially lead to funny things like this not working:

def handler(event):
    function_that_uses_syncify()
    print('Hi here')

addListener(handler)

but being fixed if we make it into async def handler.

For now a possible workaround is:

from pyodide.ffi import create_proxy
import asyncio
import js

async def async_handler():
    await asyncio.sleep(0.1)
    print('Hi there')

def handler(event):
    asyncio.create_task(async_handler()).syncify()
    print('Hi here')

handler_px = create_proxy(handler)
f = handler_px.callSyncifying.bind(handler_px)
js.document.body.addEventListener('click', f)

from pyodide.

but being fixed if we make it into async def handler.

Great! I'll try it)

For now a possible workaround is:

from pyodide.ffi import create_proxy
import asyncio
import js

async def async_handler():
    await asyncio.sleep(0.1)
    print('Hi there')

def handler(event):
    asyncio.create_task(async_handler()).syncify()
    print('Hi here')

handler_px = create_proxy(handler)
f = handler_px.callSyncifying.bind(handler_px)
js.document.body.addEventListener('click', f)

Thanks! That also can help me)
But using async handlers as default looks like better choice 😅

(Off topic, just my emotions 🌚)
I'm very excited to be (for now just a little) part of Pyodide
It sounds crazy 🤪, but I'm creating frontend framework based on Pyodide. Maybe I'm Pythonic to the core, but I believe that everything should be written in Python 🙃
So, if there is Python in browser, there should be Python frontend framework 😎
Thanks you all for your work here ♥️

from pyodide.