MacOS Python获取系统版本不对

背景

今天遇到个奇怪的问题，在conda安装软件，不能自动获取最新的版本，查看了一下info，发现里面获取的系统版本不对，开始怀疑是这个版本的问题，但是在deactive conda之后，获取的版本是正确的

conda info

显示错误的版本

在conda外面打印版本，是✅的
于是代码查看了一下，Python 源码

def mac_ver(release='', versioninfo=('', '', ''), machine=''):

    """ Get macOS version information and return it as tuple (release,
        versioninfo, machine) with versioninfo being a tuple (version,
        dev_stage, non_release_version).

        Entries which cannot be determined are set to the parameter values
        which default to ''. All tuple entries are strings.
    """

    # First try reading the information from an XML file which should
    # always be present
    info = _mac_ver_xml()
    if info is not None:
        return info

    # If that also doesn't work return the default values
    return release, versioninfo, machine

其实就是读取的 /System/Library/CoreServices/SystemVersion.plist

def _mac_ver_xml():
    fn = '/System/Library/CoreServices/SystemVersion.plist'
    if not os.path.exists(fn):
        if 'SDKROOT' in os.environ:
            fn = os.environ['SDKROOT'] + fn
            if not os.path.exists(fn):
                return None
        else:
            return None

    try:
        import plistlib
    except ImportError:
        return None

    with open(fn, 'rb') as f:
        pl = plistlib.load(f)
    release = pl['ProductVersion']
    versioninfo = ('', '', '')
    machine = os.uname().machine
    if machine in ('ppc', 'Power Macintosh'):
        # Canonical name
        machine = 'PowerPC'

    return release, versioninfo, machine

对比了2个环境的SystemVersion.plist，就是同一个，cat 出来的版本不一样
conda deactive

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>ProductBuildVersion</key>
	<string>22C65</string>
	<key>ProductCopyright</key>
	<string>1983-2022 Apple Inc.</string>
	<key>ProductName</key>
	<string>macOS</string>
	<key>ProductUserVisibleVersion</key>
	<string>13.1</string>
	<key>ProductVersion</key>
	<string>13.1</string>
	<key>iOSSupportVersion</key>
	<string>16.2</string>
</dict>
</plist>

conda active

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>ProductBuildVersion</key>
	<string>22C65</string>
	<key>ProductCopyright</key>
	<string>1983-2022 Apple Inc.</string>
	<key>ProductName</key>
	<string>Mac OS X</string>
	<key>ProductUserVisibleVersion</key>
	<string>10.16</string>
	<key>ProductVersion</key>
	<string>10.16</string>
	<key>iOSSupportVersion</key>
	<string>16.2</string>
</dict>
</plist>

都是cat的同一个路径文件，有点不理解了，都是同一个文件，为啥cat出来的内容不一样？简直反科学

同一个文件内容不一样？

网上查了下
https://stackoverflow.com/questions/69097567/macos-version-returned-as-10-16-instead-of-12-0
https://eclecticlight.co/2020/08/13/macos-version-numbering-isnt-so-simple/
大致是mac os考虑到，兼容性，在open的时候，hook掉了SystemVersion.plist，指向了 SystemVersionCompat.plis，同时留给了一个开关给我们控制，那就是环境变量SYSTEM_VERSION_COMPAT

解决办法

控制环境变量

export SYSTEM_VERSION_COMPAT = 0