Compatibility with PyMySQL == 0.9.0

[LilyMaster]

PyMySQL has been updated to 0.9.0 and has some incompatible changes. Namely, I get error:

lib/python3.6/site-packages/aiomysql/__init__.py:32: in <module>
    from .connection import Connection, connect
lib/python3.6/site-packages/aiomysql/connection.py:30: in <module>
    from pymysql.connections import _scramble
ImportError: cannot import name '_scramble'

[marcoceppi]

For those experiencing this, on a lovely Wednesday, pin PyMySQL to 0.8.1 in your setup / requirements.txt

PyMySQL==0.8.1

[arnulfojr]

And this one is related to #297, if I'm not mistaken :)
(Hope I'm saving time to someone)

[marcoceppi]

Pretty likely, the biggest issue is the way dependencies are described in this repository. They should really be pinned like

PyMySQL>=0.7.5,<0.9

The second comparison should be increased when the library is tested with each successive version of of PyMySQL. This will prevent things like a new library adding a breaking change from catching users off guard. I'll submit a PR to do just that and hopefully a patch can be cut until a more permanent patch to make this library work with PyMySQL 0.9.0

[arnulfojr]

Yea, the thing is that the release just went live some hours ago, check it out https://github.com/PyMySQL/PyMySQL/releases unfortunately we are one of the firsts to get the issue.
Quick fix should be the version limitation, proper fix should be to update the code.
Let's wait and see what the members say about it, I guess

[thesamet]

Workaround: add PyMySQL==0.7.5 to your project requirements.

[arnulfojr]

@thesamet the issue is with the latest 0.9.0 so you are safe of using the 0.8.1 as well :)

[marcoceppi]

@arnulfojr To be fair, this project is getting hit with this because PyMySQL was open ended >= whereas the rest of the dependencies (esp in requirements-dev) are ==. While not a absolute, a best practice is to do explicit pinning using either == or an upper limit. My workaround is minor, but it'll stop peoples builds from failing.

I absolutely agree aiomysql should work with 0.9 and MySQL 8 but that's likely a larger patch set.

[arnulfojr]

@marcoceppi totally agree :)

[and800]

I absolutely agree aiomysql should work with 0.9 and MySQL 8 but that's likely a larger patch set.

I don't think it is so hard. We should stop using pymysql's private api. Instead, we can for example copypaste its private objects into vendor dir, so they won't be changed by minor updates

[terricain]

Am planning to look at fixing the imports tonight, they've just moved them to the _auth module. Will also look into adding sha256 password support

[terricain]

Have MySQL 8 / sha256 support here https://github.com/terrycain/aiomysql/tree/sha256, will pr it after #309. Just thought I'd drop it incase its useful