bug#31924: 27.0.50; tramp handler /sudo::FILE fails when /bin/sh points to zsh

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

Tino Calancha <tino.calancha@gmail.com> writes:

> Hi Michael,

Hi Tino,

> I got a patch that works in my box.  It does 2 things:
>
> 1) Ensure that zsh is invoked as zsh, that is, not as sh.  Otherwise
>    our dotfiles are ignored, and we keep getting the bracketed paste
>    codes.
>    
> 2) I also need to disable the zsh option promptcr, otherwise after I
> introduce my root password, Emacs gets stuck in `tramp-wait-for-output';
> this is becuse some '\r' are added in front the prompt, so the
> regexp in ``tramp-wait-for-regexp' cannot match.

Point 2) is OK. But your solution for point 1) doesn't work in general.

> @@ -4110,7 +4112,11 @@ tramp-open-connection-setup-interactive-shell
>  process to set up.  VEC specifies the connection."
>    (let ((tramp-end-of-output tramp-initial-end-of-output)
>  	(case-fold-search t))
> -    (tramp-open-shell vec (tramp-get-method-parameter vec 'tramp-remote-shell))
> +    (tramp-open-shell
> +     vec
> +     (if (not (equal "sudo" (tramp-file-name-method vec)))
> +         (tramp-get-method-parameter vec 'tramp-remote-shell)
> +       (file-truename (tramp-get-method-parameter vec 'tramp-remote-shell))))

In tramp-sh.el, there shall be no code which relies on a given
method. Everything which is method specific, must be configured in
`tramp-methods'.

Furthermore, this code does not work at all. (file-truename "/bin/sh")
is always eval'ed on the local host, but you want to get information
about the remote host.

The better solution is to overwrite the `tramp-remote-shell' connection
property. Do something like this:

     (add-to-list 'tramp-connection-properties
                  (list (regexp-quote "/ssh:user@randomhost.your.domain:")
                        "remote-shell" "/bin/zsh"))

See the Tramp manual, (info "(tramp) Predefined connection information")

Best regards, Michael.