Subject: Re: bug#28139: 25.2; TRAMP vs bash 4.4 / readline 7.0 "bracketed paste" mode

From: Daniel Pittman <[email-masked]>
Date: Mon, 21 Aug 2017 12:01:48 -0400

On Mon, Aug 21, 2017 at 11:45 AM, Michael Albinus <[email-masked]>
wrote:
>
> Well, we have `tramp-sh-extra-args' for ages. But this doesn't work
> usually, because I don't know a bullet-proof way to detect a bash shell
> prior invocation, unless "*bash" is called.
>

*nod*  The best I can think of, since we already have the "outer" shell,
would be to invoke `/bin/sh --version -c exit`, which should work on any
basic posix shell, and will emit a bash version string for bash, then wait
for the prompt, and scan the output for the appropriate version data.

Let me contemplate about. With Emacs 26 / Tramp 2.3, we have
> connection-local variables. Maybe we could use it for your case.
>

FWIW, I already extend `tramp-actions-before-shell`, so something similarly
low level would be fine by me, to handle the custom stuff.

However, `ansi-color-filter-region` and friends from the shipped ANSI
SGR->face handling library can strip all control sequences out of a region,
or string, and might be useful here; that would allow TRAMP to become
insensitive to ANSI control codes injected anywhere into the output, which
will also fix the next time a shell decides to add some additional terminal
integration like bracketed paste mode.

If you want to apply this to streaming output, because that will rewrite
the buffer fragment with a smaller number of characters in the presence of
control codes, throw a marker at your endpoint, and retrieve the position
after the stripping, to avoid getting confused about the new offset.