Bug report

Bug description:

I encountered the following unexpected behavior when working with the new REPL on Windows 10's cmd just now:

Actual Behavior

>>> for i in range(0, 14, 2):
...     print(i, end=" ")
...
>>> 4 6 8 10 12

• When I use print and pass an argument to the end-parameter, the resulting line is missing 4 characters.
• The four chars of the REPL prompt >>> appear to write over the line, as the cursor blinks on the first visible position (indicator sits under the number 4)
• Typing overwrites the shown chars.

Expected Behavior

>>> for i in range(0, 14, 2):
...     print(i, end=" ")
...
0 2 4 6 8 10 12 >>> _

• REPL on Python 3.12 works as expected.
• Results are printed in one line, prompt appears at the end, cursor follows at end of line.

Note:

This works as expected:

>>> for i in range(0, 14, 2):
...     print(i)
...
0
2
4
6
8
10
12

CPython versions tested on:

3.13

Operating systems tested on:

Windows

Linked PRs

• gh-128067: Add newline to new REPL output when needed to avoid chopping characters #131011