HTTP view decorators (require_http_methods) not working with async views

[Hendrik Frentrup]

HTTP view decorators don't work with async views, though I don't see why they shouldn't given they don't use the ORM (unlike the login_required decorator for example).
The following throws a ValueError

@require_http_methods(['GET'])
async def blog_info(request, blog_id):
    blog = await sync_to_async(Blog.objects.get)(id=blog_id)
    return HttpResponse(f"got spot #id: {blog_id} - name: {blog.name}")

Here is the error:

ValueError: The view myapp.views.blog_info didn't return an HttpResponse object. It returned an unawaited coroutine instead. You may need to add an 'await' into your view.

From what I can see this is due to the decorator calling the async function after checking the request headers and returning but returning a non-async function (return inner) in django.views.decorators.http
How to handle middleware with async seems to be a point of contention still, but these decorators are hardly middleware, so I think it would be worth fixing. From some initial testing, it doesn't seem to be a difficult fix either.

[Hendrik Frentrup]

By the way, the initial testing yielded this [potential fix] ​https://github.com/hendrikfrentrup/django/commit/8e726875270e7a7062f246709c131915276b88ab The test for sync views all pass, but I guess a set of tests for async views would be required. Will have a look into how to write async tests. Any comments more than welcome.

[Mariusz Felisiak]

Duplicate of #31949.