v5.7.0 -w package flask to run .exe file error

[yangyuexiong]

After upgrading to v5.7.0, -w packaged the flask application, and an error occurred when running .exe. Try to add the following code in the entry file to solve this problem, and it can run successfully. If you don't add this code block, is there any other way to solve it?

`
import os
import sys

import PyInstaller

if PyInstaller.version == "5.6.2":
pass
else:
sys.stdout = open(os.devnull, "w")
`

[rokm]

If you don't add this code block, is there any other way to solve it?

No. If you use noconsole/windowed mode, you now need to set a fake sys.stdout yourself. Same as if you ran your python code in noconsole pythonw.exe interpreter.

If you want this to work without setting fake sys.stdout yourself, you should ask either flask maintainers to not call show_server_banner when sys.stdout is unavailable, or ask click maintainers to gracefully handle cases when click.utils.echo is called with unavailable file handle.

[rokm]

Also, you should not be importing PyInstaller in your application. You can safely override sys.stdout even when using PyInstaller < 5.7.

[rokm]

I've opened issue with click (pallets/click#2415) - as they are advertising click.utils.echo as replacement for print, they should be properly handling the case when console is unavailable.