Sub app middlewares are called before main app,

[Anvil]

Long story short

According to http://aiohttp.readthedocs.io/en/stable/web.html#nested-applications,
[I]f URL is '/admin/something' middlewares from [main application] are applied first and [sub application] middlewares are the next in the call chain.

It turns out it's actually the other way.

Steps to reproduce

Run this code saved as foo.py:

#!/usr/bin/python3 -tt

import aiohttp
import aiohttp.web

async def middleware1(app, next_handler):

    async def handler(request):
        print("middleware1")
        return await next_handler(request)

    return handler
    
async def middleware2(app, next_handler):

    async def handler(request):
        print("middleware2")
        return await next_handler(request)

    return handler

async def middleware3(app, next_handler):

    async def handler(request):
        print("middleware3")
        return await next_handler(request)

    return handler

app = aiohttp.web.Application(
    middlewares=[middleware1])

subapp1 = aiohttp.web.Application(middlewares=[middleware2])
app.add_subapp("/foo", subapp1)

subapp2 = aiohttp.web.Application(middlewares=[middleware3])
subapp1.add_subapp("/foo/bar", subapp2)

aiohttp.web.run_app(app, host='127.0.0.1', port=4096)

And the run wget http://127.0.0.1:4096/foo/bar.

Current Result:

$ python3 foo.py
======== Running on http://127.0.0.1:4096 ========
(Press CTRL+C to quit)
middleware3
middleware2
middleware1

Expected output:

$ python3 foo.py
======== Running on http://127.0.0.1:4096 ========
(Press CTRL+C to quit)
middleware1
middleware2
middleware3

Your environment

Ubuntu Xenial (python 3.5.2) with aiohttp 2.0.7

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