RRF_RT_REG_EXPAND_SZ bug in Windows 7

[NulAsh]

When we are calling RegGetValue and flags have RRF_RT_REG_EXPAND_SZ bit set, and RRF_NOEXPAND bit not set, function returns ERROR_INVALID_PARAMETER. This is a bug in Windows 7, not described in documentation, and was fixed in Windows 8.1. Here's the result of decompilation of buggy function in C:\Windows\syswow64\kernel32.dll:

int __stdcall RestrictArguments(int a1, int a2, int a3, int a4)
{
  if ( a1 && (_WORD)a2 && ((unsigned __int16)a2 == 0xFFFF || (a2 & 4) == 0 || (a2 & 0x10000000) != 0) && (!a3 || a4) )
    return 0;
  else
    return 87;
}

Due to this bug, py.exe from Python 3.12 does not work in Windows 7. Because _registryReadString from PC/launcher2.c have this code:

    DWORD flags = RRF_RT_REG_SZ | RRF_RT_REG_EXPAND_SZ;

    if (ERROR_SUCCESS != RegGetValueW(root, subkey, value, flags, NULL, NULL, &cbData)) {
        return 0;
    }

[vxiiduu]

Is this what causes the "unicode codec" bug? Thanks for the investigation. I will keep it in mind.

[NulAsh]

It may be the reason why Python 3.12 can't find it's own directory without explicitly specifying it in environment variables. Also this may be the reason why pip is not installed.