bug#22452: 24.4; Tramp remote shell fails on remote+sudo+homedir destination

[Ken Manheimer <ken.manheimer@gmail.com>]

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I'm glad you're investigating, Michael!

Interesting that changing tramp-verbose avoids the problem. Sounds like
that, in itself, might be a lead on the problem?

In any case, I do have a good workaround, which I'm sure you saw the reply,
in the follow-up I sent just a moment ago to you and emacs-devel. For the
sake of the bug transcript I'll repeat the substance of the message here:

I actually have a workaround, and the premise of it resides in the special
conditions I included for the repeating the problem. In order to repeat the
problem, you have to specifically use a default-directory that is set to
the remote+sudo+homedir format, and not allow something like `(cd path)' to
first resolve the home directory to an explicit path. So there's my
workaround, for multishell - use `(cd path)', rather than directly setting
default-directory.

Upshot is that I believe that there still is a bug worth unravelling
[especially since it involves an aggravating and elusive "Selecting deleted
buffer" event], in the way that shells start when default-directory is set
to remote+sudo+homedir format, but I can avoid that by using `cd'.

Ken

On Sun, Jan 24, 2016 at 12:48 PM, Michael Albinus <michael.albinus@gmx.de>
wrote:

> Ken Manheimer <ken.manheimer@gmail.com> writes:
>
> Hi Ken,
>
> > Tramp fails to start a remote shell when the remote path is exactly of
> > the form '/ssh:host|sudo:root@host:'. It fails with a message in the
> > minibuffer, "Selecting deleted buffer".
> >
> > To reproduce the error:
> >
> > * Start emacs with -Q
> > * In any buffer (*scratch* is fine):
> > M-Esc (setq default-directory
> > "/ssh:example.com|sudo:root@example.com:")
> > * In that same buffer, Esc-x shell
> >
> > This fails (with "Selecting deleted buffer") for me in the version of
> > emacs listed in the bug report and more recent versions, which I
> > compiled, eg: GNU Emacs 24.5.50.1 (x86_64-apple-darwin14.5.0, NS
> > apple-appkit-1348.17) of 2015-12-16 on twist.myriadicity.net.
> >
> > I can't get a backtrace for it, even if I set debug-on-error and
> > signal-on-error.
>
> Same here, hard to debug. The error doesn't happen if tramp-verbose is
> less than 3 prior calling M-x shell. So maybe you bind it temporarily to
> 2 in your package, as workaround.
>
> I'll continue to debug.
>
> Best regards, Michael.
>

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