On Windows, can we use `py` to shortcut the search for Python?

[cclauss]

https://docs.python.org/3/using/windows.html#getting-started recommends using py on Windows. On Linux and macOS the use of py requires an optional python-launcher add-on but on Windows, the py command has been the link to the system-wide executable since Python 3.3.

The first two lines of the log below are the right thing to do. But on lines 3 thru 5 (on Windows only!), instead of stumbling around looking for python3, should this code first be looking for py?

npm ERR! gyp verb find Python Python is not set from command line or npm configuration
npm ERR! gyp verb find Python Python is not set from environment variable PYTHON
npm ERR! gyp verb find Python checking if "python3" can be used
npm ERR! gyp verb find Python - executing "python3" to get executable path
npm ERR! gyp verb find Python - "python3" is not in PATH or produced an error
npm ERR! gyp verb find Python checking if "python" can be used
npm ERR! gyp verb find Python - executing "python" to get executable path
npm ERR! gyp verb find Python - executable path is "C:\Users\me\AppData\Local\Programs\Python\Python311\python.exe"
npm ERR! gyp verb find Python - executing "C:\Users\me\AppData\Local\Programs\Python\Python311\python.exe" to get version
npm ERR! gyp verb find Python - version is "3.11.4"
npm ERR! gyp info find Python using Python version 3.11.4 found at "C:\Users\me\AppData\Local\Programs\Python\Python311\python.exe"

@brettcannon

[brettcannon]

The tricky bit is that the Microsoft Store install (I think) doesn't come with py.

[StefanStojanovic]

To find Python, node-gyp tries various checks, and the first one that succeeds gives a path to Python to be used. The check for py exists on Windows, and is the last one in the list, so if Python is indeed installed, most likely, it will be found by some check before it. In my PR, I rearranged checks so that py gets priority over python3, python, and other known paths Python could be in. The change only affects Windows.

[cclauss]

Correct @StefanStojanovic.

I am not a Windows user so are you able to verify Brett's hunch that the Microsoft Store version does not include py?

[StefanStojanovic]

I am not a Windows user so are you able to verify Brett's hunch that the Microsoft Store version does not include py?

I tried it and it is correct - the Microsoft Store version does not include py. One more note, when installing Python manually, you have the ability not to install the py launcher, and even if you install it you can just do it for the user running the installer. So there is no guarantee that py launcher will be there (although I expect it mostly to be present).

In any case, the change I proposed here doesn't break anything (CI passed). It only reorders checks so that the py check comes before python3, python etc.

[cclauss]

Now that Python 2 is well and truly gone (1,261 days since 1/1/2020) probably looking for python first is the best strategy on Windows if and only if we can restart the search if python points to an unsupported release.

[brettcannon]

probably looking for python first is the best strategy on Windows if and only if we can restart the search if python points to an unsupported release.

python can also be from an activated virtual environment since on Windows there isn't an e.g. python3 in the virtual environment.