Async/await in Flask 2.0+ breaks due to decorator order

[phil-chp]

Name	Version
Flasgger	0.9.7.1
Flask	2.3.2
Python	3.9, 3.10
OS	macOS 13.3

I'm setting up a basic Flask project with an asynchronous route. I want to fetch information online using the selenium package, and this requires the Flask route to await for the task to finish.

I've been using @swag_from() decorators to document my code and make it easier to work with, here is an idea of what my code looked like:

@website_api.route('/get-data-from-page', methods=['POST'])
@swag_from('swagger/get-data-from-page.yml')
async def get_data_from_page():
    data = req.get_json()
    res = await common.get_data_from_page(data["url"])

    return json.dumps({ "data": res }), 201

For some reason, this kept throwing: TypeError: The view function did not return a valid response. The return type must be a string, dict, list, tuple with headers or status, Response instance, or WSGI callable, but it was a coroutine.

After a couple of hours of trying everything, re-installing Python and both libraries, I found the issue.

This causes the error:

@app.route(<route>)
@swag_from(<file>)
async def route():
    # ...

This doesn't:

@swag_from(<file>)
@app.route(<route>)
async def route():
    # ...

(Note the order of the decorators)

Now, this might not be a bug at all, it even might not have anything to do with flasgger and could be a problem is Flask directly. But the README of this project says to do it like so:

@app.route('/colors/<palette>/')
@swag_from(specs_dict)
def colors(palette):
    # ...

Maybe a switch between those two lines in the README and any documentation would be interesting?