async function support in url_defaults and url_value_preprocessor

[mozcelebi]

currently if you try to use an async function in url_defaults or url_value_preprocessor it raises

.venv/lib/python3.10/site-packages/quart/app.py:1450: RuntimeWarning: coroutine 'pull_lang_code' was never awaited

error.

The following code uses get_preferred_language from Quart-Babel extension but it could also be an async db call in an url_value_preprocessor function.

@app.url_defaults
async def add_language_code(endpoint, values):
    if app.url_map.is_endpoint_expecting(endpoint, "lang_code"):
        prefered_lang = await get_preferred_language()
        values.setdefault("lang_code", prefered_lang)

do you have any workaround/suggestions to this situation?

[mozcelebi]

I think by using the workaround mentioned in https://quart.palletsprojects.com/en/latest/discussion/async_compatibility.html this can be solved, but is looks dirty.

After adding quart flask patch

import quart_flask_patch

the following code works.

@app.url_defaults
def add_language_code(endpoint, values):
    if app.url_map.is_endpoint_expecting(endpoint, "lang_code"):
        prefered_lang = asyncio.get_event_loop().sync_wait(get_preferred_language())
        values.setdefault("lang_code", prefered_lang)

any possible roadmap to make these annotations accept not just callable but also awaitable functions?