bug#39399: tramp depends on unstable details of shell command line processing

[John F Carr]

On Feb 4, 2020, at 03:34 , Michael Albinus <michael.albinus@gmx.de> wrote:
> 
> Michael Albinus <michael.albinus@gmx.de> writes:
> 
> Hi John,
> 
>>> The terminal output from a FreeBSD 13.0 development branch system is
>>> 
>>> _echo
>>> #$ _ech ^H
>>> #$ _ec ^H
>>> #$ _e ^H
>>> #$ _ ^H
>>> #$  ^Hstty icanon erase ^H cols 32767_echo
>>> #$ stty icanon erase ^H cols 32767_ech ^H
>>> #$ stty icanon erase ^H cols 32767_ec ^H
>>> #$ stty icanon erase ^H cols 32767_e ^H
>>> #$ stty icanon erase ^H cols 32767_ ^H
>>> #$ stty icanon erase ^H cols 32767 ^H
>>> #$
>>> 
>>> with carriage returns between lines.  This does not make sense to
>>> emacs, which hangs waiting for something it recognizes.  I can recover
>>> by hitting control-G which aborts the tramp connection.
>>> 
>>> This issue is also reported to FreeBSD at
>>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=243807.
>> 
>> IIUC the discussion in that bug, it is due to the changed libedit of
>> FreeBSD 13. Hmm, don't know this beast. But wouldn't it help, if Tramps
>> sends initially "stty cooked"?
> 
> I've digged further. Likely, the problem can be avoided if we disable
> command line editing of the shell. Tramp does it already if the remote
> shell is zsh; I've added a similar parameter to the bash invocation. For
> other shells, like ksh, I haven't found a simple parameter.
> 
> For that class of shells, I've added code which installs a temporary
> ~/.editrc file, containing the line 'edit off'.
> 
> Could you please migrate to Tramp 2.4.3.1 from GNU ELPA? On top of this,
> install the appended patch.
> 
> And pls report, whether it works for you.
> 
> Best regards, Michael.
> 
> <Mail Attachment>

Your change applied to tramp 2.4.3 from ELPA works.