Sanic: Multidict version 4.7.0 breaks Sanic

[omab]

Describe the bug
multidict project just released (1 hour ago) their version 4.7.0 (https://pypi.org/project/multidict/#history), this includes a change that breaks Sanic Header class definition.

----> 1 import sanic

/usr/local/lib/python3.7/site-packages/sanic/__init__.py in <module>
      1 from sanic.__version__ import __version__
----> 2 from sanic.app import Sanic
      3 from sanic.blueprints import Blueprint
      4 
      5 

/usr/local/lib/python3.7/site-packages/sanic/app.py in <module>
     16 
     17 from sanic import reloader_helpers
---> 18 from sanic.asgi import ASGIApp
     19 from sanic.blueprint_group import BlueprintGroup
     20 from sanic.config import BASE_LOGO, Config

/usr/local/lib/python3.7/site-packages/sanic/asgi.py in <module>
     20 import sanic.app  # noqa
     21 
---> 22 from sanic.compat import Header
     23 from sanic.exceptions import InvalidUsage, ServerError
     24 from sanic.log import logger

/usr/local/lib/python3.7/site-packages/sanic/compat.py in <module>
      2 
      3 
----> 4 class Header(CIMultiDict):
      5     def get_all(self, key):
      6         return self.getall(key, default=[])

TypeError: type 'multidict._multidict.CIMultiDict' is not an acceptable base type

Code snippet

$ pip install -U multidict==4.7.0
$ python -m sanic

Expected behavior
Sanic module imports correctly.

Environment (please complete the following information):

• OS: Linux (docker)
• Version: 19.9.0
• Python: 3.7.3

Additional context
No extra context

[optroodt]

I get the same thing in my CI builds:

    from sanic.response import HTTPResponse
/usr/local/lib/python3.6/site-packages/sanic/__init__.py:2: in <module>
    from sanic.app import Sanic
/usr/local/lib/python3.6/site-packages/sanic/app.py:18: in <module>
    from sanic.asgi import ASGIApp
/usr/local/lib/python3.6/site-packages/sanic/asgi.py:22: in <module>
    from sanic.compat import Header
/usr/local/lib/python3.6/site-packages/sanic/compat.py:4: in <module>
    class Header(CIMultiDict):
E   TypeError: type 'multidict._multidict.CIMultiDict' is not an acceptable base type

Environment (please complete the following information):

• OS: Linux (docker)
• Version: 19.9.0
• Python: 3.6.9

[omab]

Downgrading to multidict==4.6.1 fixes the problem.

[qwesda]

The error occurs because the cimultidict_type does not have the Py_TPFLAGS_BASETYPE flag set ...

• cimultidict_type without Py_TPFLAGS_BASETYPE
  https://github.com/aio-libs/multidict/blob/d786088778285ba56e06c992f44e546fb4c7b74b/multidict/_multidict.c#L1007

• multidict_type with Py_TPFLAGS_BASETYPE
  https://github.com/aio-libs/multidict/blob/d786088778285ba56e06c992f44e546fb4c7b74b/multidict/_multidict.c#L948

I reported the issue https://github.com/aio-libs/multidict/issues/416 and made a PR I also made a PR https://github.com/aio-libs/multidict/pull/417 ... a lot of boilerplate for 44 bytes

[greatvovan]

Only the latest Sanic version 19.9.0 fail as well as 19.6.3. Version 19.6.2 (and older) works well with multidict==4.7.0.

[greatvovan]

Also, interestingly, both 19.9.0 and 19.6.3 work on my machine with my local Python 3.8.0 (built with pyenv, Mac OS 10.15), but both don't work in the official Python Docker image 3.8.

[bidyottama278]

Here am also getting the same issue

File "/usr/local/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/local/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/local/src/app.py", line 1, in <module>
    from sanic import Sanic, response
  File "/root/.local/share/virtualenvs/lib/python3.7/site-packages/sanic/__init__.py", line 2, in <module>    from sanic.app import Sanic
  File "/root/.local/share/virtualenvs/lib/python3.7/site-packages/sanic/app.py", line 18, in <module>
    from sanic.asgi import ASGIApp
  File "/root/.local/share/virtualenvs/lib/python3.7/site-packages/sanic/asgi.py", line 22, in <module>
    from sanic.compat import Header
  File "/root/.local/share/virtualenvs/lib/python3.7/site-packages/sanic/compat.py", line 4, in <module>
    class Header(CIMultiDict):
TypeError: type 'multidict._multidict.CIMultiDict' is not an acceptable base type

am using python 3.7.2 version and sanic=* is in my pipfile
which version of sanic i should use here ?

[allenchou13]

Sanic version 19.6.2 work on my machine

[jkanche]

downgrading multidict to 4.6.1 fixed the problem for me!

[qwesda]

My PR is merged - hope 4.7.1 will come out soon

[bidyottama278]

Thanks all for these responses.. multidict 4.6.1 is working for me.

[omab]

@qwesda, I confirm the error is gone with the new multidict==4.7.1.

Thanks!

[balakumar98]

Downgrading to multidict==4.6.1 fixes the problem.

requires 4.7.1 or above

[ahopkins]

Has anyone run Sanic with multidict==4.7.1?

[omab]

@ahopkins, I'm using it, no issues so far.