Adding into Path var while silent installation of Python - possible bug?

Question

I need to passively install Python in my applications package installation so i use the following:

python-3.5.4-amd64.exe /passive PrependPath=1

according this: 3.1.4. Installing Without UI I use the PrependPath parameter which should add paths into Path in Windows environment variables.

But it seems not to work. The variables does not take any changes.

If i start installation manually and select or deselect checkbox with add into Paths then everything works.

Works same with clear installation also on modify current installation. Unfortunately i do not have other PC with Win 10 Pro to test it.

I have also tried it with Python 3.6.3 with same results.

EDIT:

Also tried with PowerShell Start-Process python-3.5.4-amd64.exe -ArgumentList /passive , PretendPath=1 with same results.

Also tested on several PCs with Windows 10, same results, so the problem is not just on single PC

EDIT: Of cource all attempts were run as administrator.

Answer 1

Ok, from my point of view it seems to be bug in Python Installer and I can not find any way how to make it works.

I have founds the following workaround:

Use py.exe which is wrapper for all version of Python on local machine located in C:\Windows so you can run it directly from CMD anywhere thanks to C:\Windows is standard content of Path variable.

py -3.5 -c "import sys; print(sys.executable[:-10])"

This gives me directory of python 3.5 installation.

And then i set it into Path manually by:

setx Path %UserProfile%";PythonLocFromPreviousCommand