python3.x下pip报错No module named 'ConfigParser'

cygwin下virtual-env的python3.6下安装 MySQL-python报错，错误消息如后，提示找不到ConfigParser模块，而事实上该模块在python3.x后改名了。那就照旧名做个包，引用进去。

文件 /path-to-you-python/site-packages/ConfigParser.py

内容如下（事实上只要第二行就行），再运行正常了。（当然mysql-python的其他依赖包之前已经安装过。）

"""compatible configparser"""
from configparser import *

$ pip install MySQL-python
Looking in indexes: https://mirrors.ustc.edu.cn/pypi/web/simple
Collecting MySQL-python
  Downloading https://mirrors.ustc.edu.cn/pypi/web/packages/a5/e9/51b544da85a36a68debe7a7091f068d802fc515a3a202652828c73453cad/MySQL-python-1.2.5.zip (108kB)
    100% |████████████████████████████████| 112kB 799kB/s
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "", line 1, in 
      File "/tmp/pip-install-pasqnywc/MySQL-python/setup.py", line 13, in 
        from setup_posix import get_config
      File "/tmp/pip-install-pasqnywc/MySQL-python/setup_posix.py", line 2, in 
        from ConfigParser import SafeConfigParser
    ModuleNotFoundError: No module named 'ConfigParser'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-install-pasqnywc/MySQL-python/
(py36)

python3.x下pip安装 pymysql 代替MySQL-python 的方案

MySQL-python/MySQLdb 模块实在太久没有更新了，MariaDB发布后，其devel包的文件与mysql-devel有所不同，将造成编译失败。网上有hack方案，照着做补丁编译实在太麻烦，其实完全可以使用pymysql代替。

pip install pymysql

安装pymysql

新建个文件 /path-to-you-python/site-packages/MySQLdb.py 内容如下

"""compatible MySQLdb"""
from pymysql import *
install_as_MySQLdb()

完工。

前述的错误消息示例如后。如果还没安装mysql-devel包，报错将如下：

    _mysql.c:44:10: fatal error: my_config.h: No such file or directory
     #include "my_config.h"

装过MariaDB的devel包安装会报如下编译错误：

    In file included from _mysql.c:44:0:
    /usr/include/mysql/my_config.h:3:2: warning: #warning This file should not be included by clients, include only <mysql.h> [-Wcpp]
     #warning This file should not be included by clients, include only <mysql.h>
      ^~~~~~~