Python 3.13 and 3.14 REPL on Windows Terminal is chopping off the first four characters printed if `end` parameter is used in `print` function

[journpy]

Bug report

Bug description:

If I use the end parameter in print function, the first four characters (including whitespaces) of the output are chopped off. I have tried using other Python versions (3.10 - 3.12) and everything works well. It is somewhat strange that this happens only on Python 3.13 REPL in Windows Terminal or Command Prompt. Consider the MRE below:

for i in range(10):
   print(i, end='')

prints: 456789. Numbers 0, 1, 2, and 3 are missing.

Also

print('first', end='|')

prints t| instead of first|. Characters 'f', 'i', 'r', 's' are missing.

My specific version is Python 3.13.0. I'd like to know if this is happening because I'm on a Windows machine or is it an issue with Python 3.13.0? Thanks.

CPython versions tested on:

3.10, 3.11, 3.12, 3.13

Operating systems tested on:

Windows

[picnixz]

Can you test with the latest Python 3.13 release? we're currently at 3.13.1. I cannot reproduce this on Linux and on 3.14.

[eendebakpt]

I can confirm this issue on latest main (Windows). It might be the first three characters are printed, but then overwritten by the prompt >>>

[picnixz]

cc @pablogsal

[pablogsal]

Unfortunately I don't have a windows machine at the moment 😕. @DinoV @zooba @ambv can you take a look if you have some free cycles?

[rruuaanng]

The strange thing is that it seems to be related to outputting end.