sphinx-quickstart shows Mojibake characters around a question line

[t2y]

Describe the bug

sphinx-quickstart command asks some questions, however it shows Mojibake characters around question lines. See below screenshot.

I guess this issue is my environment issue and not come from sphinx. But, I file to share as an information. Hopefully, someone shares us how to resolve.

To Reproduce

Steps to reproduce the behavior:

(sphinx3) $ pip install sphinx
(sphinx3) $ sphinx-quickstart --version
sphinx-quickstart 2.3.1

(sphinx3) $ export LANG=en_US.UTF-8
(sphinx3) $ sphinx-quickstart 

(sphinx3) $ LC_ALL=C.UTF-8 sphinx-quickstart

Expected behavior

There are no Mojibake characters.

Screenshots

Environment info

• OS: [Ubuntu 18.04.3]

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 18.04.3 LTS
Release:	18.04
Codename:	bionic

• Python version: [3.8.1]
• Sphinx version: [2.3.1]
• Sphinx extensions: [none]
• Extra tools: [gnome-terminal]

$ gnome-terminal --version
# GNOME Terminal 3.28.2 using VTE 0.52.2 +GNUTLS -PCRE2

[t2y]

I found that python interpreter in my environment didn't have readline extension.

WARNING: The Python readline extension was not compiled. Missing the GNU readline lib?

After I installed libreadline-dev and re-compiled python interpreter, I confirmed this issue won't be reproduced.

$ sudo apt install -y libreadline-dev
$ pyenv install 3.8.1

[tk0miya]

It seems escape sequence characters for readline are output even if the library not found. Finally I can't create the reproducible environment. But I suppose this can be fixed.