#! /usr/bin/env pythonw shebang causes "[ERROR] No runtime installed that matches w. Try running "py install w"."

[DervishD]

Install source and version

• Installed from the Windows Store
• Installed with the MSIX from python.org
• Installed with the MSI from python.org
• Installed with winget install 9NQ7512CXL7T

Version:
25.0

Describe the bug
Using this minimal script for testing, named t.pyw:

#! /usr/bin/env pythonw

import sys
import time
from ctypes import windll

windll.user32.MessageBoxW(None, "Script started", "Hi", 0x10)

print('This goes to stdout', file=sys.stdout)
time.sleep(3)
print('This goes to stderr', file=sys.stderr)
time.sleep(3)

windll.user32.MessageBoxW(None, "Script finished", "Done", 0x10) 

If launched using double click it does not do anything. If launched using py t.pyw, the error message [ERROR] No runtime installed that matches w. Try running "py install w". is produced. For some reason the shebang is not processed properly, and in fact the shebang #! /usr/bin/env pyw works perfectly, don't know why.

To Reproduce
Steps to reproduce the behavior:

1. Open a command prompt.
2. Run py t.pyw
3. See error

Expected behavior
A normal run, just like when the #! /usr/bin/env pyw is used, or like the #! /usr/bin/env python3 shebang with the legacy installer. The real script which triggered this for me was working perfectly with the legacy installer/launcher and the #! /usr/bin/env python3 shebang.

[zooba]

Ah, we must need to search for pythonw before python<TAG>. That should be easy enough to do

[DervishD]

Thanks a lot! It's not a serious issue, because can be easily fixed by temporarily adjusting the shebang to use pyw instead, but anyway it would be a very useful fix. I'll keep an eye on updates!

Again, thanks for the promptly response 😄