MultipartReader doesn't work with -OO

[iceboy233]

Long story short

MultipartReader doesn't work when -OO is enabled on python interpreter.

Expected behaviour

from aiohttp import web

async def hello(request):
    async for part in await request.multipart():
        print(part.name)
    return web.Response()

app = web.Application()
app.router.add_post('/', hello)
web.run_app(app)

curl 'http://localhost:8080' \
    -H 'content-type: multipart/form-data; boundary=----BOUNDARY' \
    --data-binary $'------BOUNDARY\r\nContent-Disposition: form-data; name="key"\r\n\r\nvalue\r\n------BOUNDARY--\r\n'

Actual behaviour

When -OO is enabled (e.g. python3 -OO a.py), the request handling fails:

Error handling request
Traceback (most recent call last):
  File "/home/iceboy/.local/lib/python3.5/site-packages/aiohttp/web_protocol.py", line 421, in start
    resp = yield from self._request_handler(request)
  File "/home/iceboy/.local/lib/python3.5/site-packages/aiohttp/web.py", line 303, in _handle
    resp = yield from handler(request)
  File "a.py", line 4, in hello
    async for part in await request.multipart():
  File "/home/iceboy/.local/lib/python3.5/site-packages/aiohttp/multipart.py", line 560, in __anext__
    part = yield from self.next()
  File "/home/iceboy/.local/lib/python3.5/site-packages/aiohttp/multipart.py", line 594, in next
    yield from self._read_boundary()
  File "/home/iceboy/.local/lib/python3.5/site-packages/aiohttp/multipart.py", line 689, in _read_boundary
    % (chunk, self._boundary))
ValueError: Invalid boundary b'', expected b'------BOUNDARY'

Your environment

python 3.5.2
aiohttp 2.1.0

[asvetlov]

Just for curiosity: why do you use optimization levels?

[iceboy233]

Just for curiosity: why do you use optimization levels?

In the hope that it could be faster.

More interestingly benchmark shows that it's often slower (in 1-2%) with -OO. There must be something wrong.

[asvetlov]

Python has very subtle optimizations on -OO, I think this mode is useless.

[fafhrd91]

it disables assert and __debug__ which gives some improvement for benchmarks. For production it useless

[fafhrd91]

fixed in master

@kxepal you should be careful with assert, it should not have side-effects

[kxepal]

Good catch! My bad to forget about PYTHONOPTIMIZE mode /)_-

[lock]

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