M2 Mac部署mysqlclient遇_mysql_affected_rows符号缺失及架构疑问

问题背景 #

新M2 MacBook部署环境时，碰到了GitHub issue#496里的M1同款问题：pip安装的MySQLdb共享对象库与brew安装的mysqlclient dylib因x86/arm架构不匹配，导致符号不一致。折腾一周试遍issue里的各种方案都无效，对底层库架构相关知识不熟悉，希望找到遗漏的解决点。线程里大量带arch参数的安装、执行组合我试了很多，但完全不懂背后原理。

环境信息 #

Python版本 #

$ file $(which python)
/Users/sbrown/.virtualenvs/mypkg/bin/python: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64:Mach-O 64-bit executable arm64]
/Users/sbrown/.virtualenvs/mypkg/bin/python (for architecture x86_64):  Mach-O 64-bit executable x86_64
/Users/sbrown/.virtualenvs/mypkg/bin/python (for architecture arm64):   Mach-O 64-bit executable arm64

brew安装的libmysqlclient #

$ file /opt/homebrew/opt/mysql-client/lib/libmysqlclient.21.dylib
/opt/homebrew/opt/mysql-client/lib/libmysqlclient.21.dylib: Mach-O 64-bit dynamically linked shared library arm64

pip安装的mysqlclient #

$ file ~/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/_mysql.cpython-311-darwin.so
/Users/sbrown/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/_mysql.cpython-311-darwin.so: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit bundle x86_64] [arm64:Mach-O 64-bit bundle arm64]
/Users/sbrown/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/_mysql.cpython-311-darwin.so (for architecture x86_64):   Mach-O 64-bit bundle x86_64
/Users/sbrown/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/_mysql.cpython-311-darwin.so (for architecture arm64):    Mach-O 64-bit bundle arm64

核心疑问 #

1. symbols命令输出能比file提供更多架构相关信息吗？ #

GitHub线程里多次提到用symbols <library file> | grep mysql_affected_rows判断架构，但没人解释怎么从输出判断。我在正常运行的旧x86 MacBook上得到如下输出，和线程里一致：

$ symbols /opt/homebrew/opt/mysql-client/lib/libmysqlclient.21.dylib | grep mysql_affected_rows
            0x0000000000011c98 (     0x8) mysql_affected_rows [FUNC, EXT, NameNList, MangledNameNList, Merged, NList, FunctionStarts]

$ symbols ~/.virtualenvs/llatitude/lib/python3.11/site-packages/MySQLdb/_mysql.cpython-311-darwin.so | grep mysql_affected_rows
            0x0000000000006dcc (     0xc) DYLD-STUB$$mysql_affected_rows [DYLD-STUB, LENGTH, NameNList, MangledNameNList, NList]

2. 通用二进制的架构选择由什么决定？ #

我尝试多种方案后，用两种arch参数执行测试命令均失败：

$ arch -arm64 python -c 'import MySQLdb'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/sbrown/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/__init__.py", line 17, in <module>
    from . import _mysql
ImportError: dlopen(/Users/sbrown/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/_mysql.cpython-311-darwin.so, 0x0002): symbol not found in flat namespace '_mysql_affected_rows'

$ arch -x86_64 python -c 'import MySQLdb'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/sbrown/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/__init__.py", line 17, in <module>
    from . import _mysql
ImportError: dlopen(/Users/sbrown/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/_mysql.cpython-311-darwin.so, 0x0002): symbol not found in flat namespace '_mysql_affected_rows'

3. 上述错误是指.so文件找不到符号，还是调用外部库时找不到符号？ #

otool -tV输出如下：

$ otool -tV ~/.virtualenvs/mypkg/lib/python3.11/site-packages/MySQLdb/_mysql.cpython-311-darwin.so | grep mysql_affected_rows
0000000000005711    callq   0x70b8                          ## symbol stub for: _mysql_affected_rows
0000000000004cc0    bl  0x6dcc ; symbol stub for: _mysql_affected_rows

求助 #

这类基础问题不该卡这么久，但我实在不知道下一步该怎么做，有没有我忽略的解决路径？

内容的提问来源于stack exchange，提问作者Scott