Show the version of Python Launcher for Windows

[oleksis]

Feature or enhancement

Ability to return the version of Python Launcher for Windows running through the argument -V or --version

Pitch

Motivation

Starting with Python 3.11, Python Launcher for Windows has been included

One way to know the version of the py launcher that is running is through the argument '--help' and read the first line of the help content

The following behavior is desired if the argument '--version' is added

➜ $env:PY_PYTHON='3.10'
 
➜ .\PCbuild\amd64\py_d.exe -V
Python Launcher for Windows Version 3.11.1+
Python 3.10.9

➜ .\PCbuild\amd64\py_d.exe --version
Python Launcher for Windows Version 3.11.1+
Python 3.10.9

➜ .\PCbuild\amd64\py_d.exe -V:3.10 -V
Python 3.10.9

➜ .\PCbuild\amd64\py_d.exe -V:3.10 --version
Python 3.10.9

Previous discussion

Linked PRs

• [3.11] Show the Python Launcher version (GH-100829) #100831
• gh-100829: Show the Python Launcher version #100832

[bedevere-bot]

GH-100831 is a backport of this pull request to the 3.11 branch.

[eryksun]

This will break any tool that depends on parsing the known output format of py -V. Maybe introduce a new "--version-launcher" option.

[oleksis]

This will break any tool that depends on parsing the known output format of py -V. Maybe introduce a new "--version-launcher" option.

The new "--version-launcher" option will show the version info and exit or pass extra arguments to the Python py launcher finded ?

[oleksis]

@eryksun thanks for the feedback i make the changes

➜ $env:PY_PYTHON='3.10'
 
➜ .\PCbuild\amd64\py_d.exe -V
Python 3.10.9

➜ .\PCbuild\amd64\py_d.exe -V:3.10 --version
Python 3.10.9

➜ .\PCbuild\amd64\py_d.exe -0v
Python Launcher for Windows Version 3.12.0a3+

➜ .\PCbuild\amd64\py_d.exe --version-launcher
Python Launcher for Windows Version 3.12.0a3+

[eryksun]

You may be better off using SearchPathW() to find the path of "py.exe" and then calling GetFileVersionInfo(). For example, the following uses PyWin32 to inspect the version of the launcher:

>>> py_path = win32api.SearchPath(None, 'py.exe')[0]
>>> info = win32api.GetFileVersionInfo(py_path, '\\')
>>> info['ProductVersionMS'] >> 16
3
>>> info['ProductVersionMS'] & 0xFFFF
11
>>> info['ProductVersionLS'] >> 16
1150
>>> info['ProductVersionLS'] & 0xFFFF
1013

The final value, 1013, is the Python API version, which isn't relevant to the launcher. The third value, 1150, is the micro version number times 1000, plus the release level times 10, plus the release serial number. In this case, the micro version number is 1 (i.e. it's version 3.11.1), the release level is 15, and the release serial is 0. The release levels are defined in Include/patchlevel.h:

cpython/Include/patchlevel.h

Lines 10 to 15 in 951303f

	/* Values for PY_RELEASE_LEVEL */
	#define PY_RELEASE_LEVEL_ALPHA 0xA
	#define PY_RELEASE_LEVEL_BETA 0xB
	#define PY_RELEASE_LEVEL_GAMMA 0xC /* For release candidates */
	#define PY_RELEASE_LEVEL_FINAL 0xF /* Serial should be 0 here */
	/* Higher for patch releases */

[oleksis]

The launcher have the Version defined as string: PY_VERSION

[eryksun]

What I meant is that if you're only concerned with the py launcher on Windows, then using GetFileVersionInfo() will work for all versions of both the old launcher ("launcher.c") and the new launcher ("launcher2.c").

[oleksis]

I make the changes for using the new launcher ("launcher2.c") on Python 3.11+

[jaraco]

I'd recommend not to add variance with the Python launcher for Unix. Ideally these two launchers should converge. Adding changes that apply to only one because they happen to be separate implementations at the moment will only decrease the ability to converge these implementations.

Can you explain more about the motivation for the version? The current launcher already reports the version:

PS C:\Users\jaraco> py -V
Python 3.11.0b3
PS C:\Users\jaraco> py --version
Python 3.11.0b3

How is --version-launcher different from --version?

[oleksis]

How recommended @eryksun adding the output to the version of the Python will break tool depending that behaviour.

Other point is if the argument for Version action will be redirected to the same Version argument option to the Python found

The Python Launcher for Unix until today don't have Version option for the launcher. Here the discussion

Open to the ideas 💡

[brettcannon]

How is --version-launcher different from --version?

The feature request is to know the version of the Launcher itself, not the version of Python that the Launcher will run on your behalf.

But one thing that isn't clear to me is what's the use case for knowing the version of the Launcher (which in the Windows case is the version of Python it was installed with)? And is the use case important enough to complicate the API for the Launcher to add another flag that's explicit to the Launcher and something it has to capture instead of launching Python?

[oleksis]

Thinking in the future, using only the Python Launcher (new version can install other Python) for integration with others tools like Visual Studio Code, DevContainer Features, (python-launcher feature) will easy to check what version of the Python-Launcher is available in the system