[winreg] How to access "(Default)" key value?

[MRAB]

On 2022-05-03 10:31, Nicolas Formichella wrote:
> Hello,
> 
> I am encountering an issue with winreg, I can't figure out how to read the "(Default)" of a registry value
> 
> ```
> def get_chrome_version() -> str:
>      with winreg.ConnectRegistry(None, winreg.HKEY_CURRENT_USER) as registry:
>          with winreg.OpenKeyEx(registry, r"Software\Microsoft\Windows\CurrentVersion\App Paths\chrome.exe",
>                                access=winreg.KEY_READ) as key:
>              value, _ = winreg.QueryValueEx(key, "(default)")
>      return value
> ```
> 
> Taking the example above it raises a FileNotFoundError :
> 
> ```
> Traceback (most recent call last):
>    File "C:/Users/noulo/dev/py/chromedriver_dl/main.py", line 14, in get_chrome_version
>      value, _ = winreg.QueryValueEx(key, "(default)")
> FileNotFoundError: [WinError 2] The system cannot find the file specified
> ```
> 
> (Trying "Path" instead of "(Default)" works)
> 
> Although the value definitely exists as shown by Powershell
> 
> ```
> Get-Item -Path  "HKCU:/Software/Microsoft/Windows/CurrentVersion/App Paths/chrome.exe" | Select-Object -ExpandProperty Property
> ```
> 
> Returns :
> 
> ```
> (default)
> Path
> ```
> 
> Is this a bug I should report, or if not, what is the way, using winreg, to access the "(Default)" value of a key?
> 
Use 'QueryValue' with an empty string:

     value = winreg.QueryValue(key, "")

or None:

     value = winreg.QueryValue(key, None)