bug#34192: 26.1; Bash 5.0 breaks TRAMP sudo

[Michael Albinus <michael.albinus@gmx.de>]

Allen Li <darkfeline@felesatra.moe> writes:

Hi Allen,

> I finally traced the problem down to setting tramp-histfile-override to t.
>
> Apparently, Bash 5.0 doesn't like HISTSIZE=0.  Changing it to
> HISTSIZE=1 fixes the error.

Is this new in bash 5.0? I have installed GNU bash 4.4.19, and its
info manual says:

--8<---------------cut here---------------start------------->8---
'HISTSIZE'
     The maximum number of commands to remember on the history list.  If
     the value is 0, commands are not saved in the history list.
     Numeric values less than zero result in every command being saved
     on the history list (there is no limit).  The shell sets the
     default value to 500 after reading any startup files.
--8<---------------cut here---------------end--------------->8---

Hmm, there's exactly the same text in
https://ftp.gnu.org/gnu/bash/bash-5.0.tar.gz/bash-5.0/doc/bash.info

Before changing Tramp, I'd like to understand what's up.

> Reproduce:
>
> 1. emacs -Q
> 2. (setq tramp-histfile-override t)
> 3. C-x C-f /sudo::/ TAB <enter sudo password> RET

Do you have some special settings in your remote .profile,
.bash_profile, .bash_login, or .bashrc?  Could you test with moving
these files away?

Best regards, Michael.