Weird behaviour with tmux send-keys

Bug report

Bug description:

Hi,

I'm experiencing some weird behaviour only in python 3.13, up to 3.12, this bug never appeared. I'm gonna try to explain it in the best possible way..

I use tmux send-keys to send a couple lines to my python prompt, to run a script from within the python interpreter, clear vars, change the working directory, etc. Now, in python 3.13, after a couple times of sending text to the python prompt this way, some weird behaviour happens.

I'm gonna make a simple example, let's say i send the text (again, using tmux send-keys function) to my python (3.13) prompt:

a = 3\u000D

Which would be a var definition + Enter, if i open a pytho nprompt and do that, it works perfect, now, after a while of sending text this way, when i do it again, the line doesn't get executed, in the prompt "appears" the first char in the line that i sent (in this example, "a"), and it the prompt gets like "paused". If i press any key on it, the line goes through. and it works normally.

This only happens to me in 3.13, i'm not sure if it's a tmux or python issue, my guess is python.

Any idea what could this be, or has anyone experienced something similar?

Thanks in advance !

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Tái hiện hành vi trong prompt Python 3.13 trên Linux bằng tmux send-keys, sau đó so sánh với Python 3.12 và xác định tmux hay Python là nguyên nhân. Xác nhận vấn đề bằng một chuỗi tối thiểu có thể lặp lại và ghi lại thay đổi hoặc bài kiểm thử nào sẽ chứng minh rằng prompt không còn tạm dừng.