Bug with new lines

[Шкіпер Десна]

Hello!
If I use something like `***@localhost:/folder$ echo -n 123`, then in a
new line before 'user...' I see '123', but it's yet normal, but if I use
something like `***@localhost:/folder$ echo -n $(echo 123)` or
`***@localhost:/folder$ printf %s 123`, it may seem that everything is in
order, but if I tap up (to copy previous command) and then tap down (to
back), Bash will leave from start so many chars, like '***@localhost:/folder$
' has, i.e., I'll get '***@localhost:/folde'. The only way to repair it is
to press "enter". If I just press up after `***@localhost:/folder$ printf
%s 123`, then nothing unusual happens — it appends the previous command
after '...$ ', like usual ('123' in the beginning doesn't disappear). If I
tap it again, some many times, again nothing unusual, but once it will cut
the ending of '***@localhost:/folder$ '. I don't know exactly where the
logic is. If I tap up twice or more, but the ending yes hasn't been
clipped, I can tap down and it won't be clipped, for except the last tap,
when I get the current command.
Best regards,
Shkiper Desna.

[Chet Ramey]

Post by Шкіпер Десна
Hello!
new line before 'user...' I see '123', but it's yet normal, but if I use
order, but if I tap up (to copy previous command) and then tap down (to
%s 123`, then nothing unusual happens — it appends the previous command
after '...$ ', like usual ('123' in the beginning doesn't disappear). If I
tap it again, some many times, again nothing unusual, but once it will cut
logic is. If I tap up twice or more, but the ending yes hasn't been
clipped, I can tap down and it won't be clipped, for except the last tap,
when I get the current command.

This isn't a bug. Readline assumes it can use the entire line for redisplay
and that it starts in column 0. Any text can be overwritten otherwise.

Here are a few links to recent discussions of the issue.

https://lists.gnu.org/archive/html/bug-bash/2020-01/msg00005.html
https://lists.gnu.org/archive/html/bug-bash/2020-02/msg00002.html

Chet