Subject: Re: bug#34943: 27.0.50; Tramp explicte-shell-file-name not work and not safe local variable

From: Shuguang Sun <[email-masked]>
Date: Sat, 23 Mar 2019 12:13:52 +0800

Michael Albinus <[email-masked]> writes:

> Shuguang Sun <[email-masked]> writes:
>
>> Hi,
>
>> The recent change to Tramp for shell/explict shell has break the remote shell again. For example:
>> - Tramp to a host
>> - in a remote diretory, M-x shell
>>   it raise the error message: env path/to/cmdproxy.exe can't be found
>>   which looks tramp shell invoke the local shell, instead the remote shell
>>
>> I have the settings:
>> ```
>>   (connection-local-set-profile-variables
>>    'remote-bash
>>    '((explicit-shell-file-name . "/bin/bash")
>>      (explicit-bash-args . ("-i"))
>>      ))
>>
>>   (connection-local-set-profiles
>>    '(:application tramp :protocol "plink" :user "user" :machine "host.com")
>>    'remote-bash)
>> ```
>> In the previous version of tramp (about Feb), it will invoke the explicit-shell-file-name, instead of local cmdproxy.
>
> If `explicit-shell-file-name' is given, it must have precedence. What
> about the following patch to master:
>
> *** /tmp/ediffWyfTux	2019-03-22 15:09:52.065151959 +0100
> --- /home/albinus/src/emacs/lisp/shell.el	2019-03-22 15:09:35.080867417 +0100
> ***************
> *** 721,729 ****
>                    (current-buffer)))
>
>     (with-current-buffer buffer
> !     (when (file-remote-p default-directory)
> !       ;; On remote hosts, the local `shell-file-name' might be useless.
> !       (with-connection-local-variables
>          (if (and (called-interactively-p 'any)
>                   (null explicit-shell-file-name)
>                   (null (getenv "ESHELL")))
> --- 721,729 ----
>                    (current-buffer)))
>
>     (with-current-buffer buffer
> !     (with-connection-local-variables
> !      ;; On remote hosts, the local `shell-file-name' might be useless.
> !      (when (file-remote-p default-directory)
>          (if (and (called-interactively-p 'any)
>                   (null explicit-shell-file-name)
>                   (null (getenv "ESHELL")))
> ***************
> *** 732,757 ****
>   		 (expand-file-name
>                     (read-file-name
>                      "Remote shell path: " default-directory shell-file-name
> !                    t shell-file-name))))))))
>
> !   ;; The buffer's window must be correctly set when we call comint
> !   ;; (so that comint sets the COLUMNS env var properly).
> !   (pop-to-buffer buffer)
> !   ;; Rain or shine, BUFFER must be current by now.
> !   (unless (comint-check-proc buffer)
> !     (let* ((prog (or explicit-shell-file-name
> !                      (getenv "ESHELL") shell-file-name))
> !            (name (file-name-nondirectory prog))
> !            (startfile (concat "~/.emacs_" name))
> !            (xargs-name (intern-soft (concat "explicit-" name "-args"))))
> !       (unless (file-exists-p startfile)
> !         (setq startfile (concat user-emacs-directory "init_" name ".sh")))
> !       (apply #'make-comint-in-buffer "shell" buffer prog
> !              (if (file-exists-p startfile) startfile)
> !              (if (and xargs-name (boundp xargs-name))
> !                  (symbol-value xargs-name)
> !                '("-i")))
> !       (shell-mode)))
>     buffer)
>
>   ;;; Directory tracking
> --- 732,757 ----
>   		 (expand-file-name
>                     (read-file-name
>                      "Remote shell path: " default-directory shell-file-name
> !                    t shell-file-name))))))
>
> !      ;; The buffer's window must be correctly set when we call comint
> !      ;; (so that comint sets the COLUMNS env var properly).
> !      (pop-to-buffer buffer)
> !      ;; Rain or shine, BUFFER must be current by now.
> !      (unless (comint-check-proc buffer)
> !        (let* ((prog (or explicit-shell-file-name
> !                         (getenv "ESHELL") shell-file-name))
> !               (name (file-name-nondirectory prog))
> !               (startfile (concat "~/.emacs_" name))
> !               (xargs-name (intern-soft (concat "explicit-" name "-args"))))
> !          (unless (file-exists-p startfile)
> !            (setq startfile (concat user-emacs-directory "init_" name ".sh")))
> !          (apply #'make-comint-in-buffer "shell" buffer prog
> !                 (if (file-exists-p startfile) startfile)
> !                 (if (and xargs-name (boundp xargs-name))
> !                     (symbol-value xargs-name)
> !                   '("-i")))
> !          (shell-mode)))))
>     buffer)
>
>   ;;; Directory tracking
>

The patch works. Thanks.

>
>> Another issue, the emacs treat explicit-shell-file-name and explicit-bash-args
>> as non-safe local variables and ask how to deal it (Y/N/! ...).
>> In the previous version of tramp (about Feb), it takes these two variables as
>> safe which I think is reasonable because user sets it in tramp-way explicitely
>> and it is only used in tramp only.
>
> I'll check when the first problem is solved.

FYI. explicit-shell-file-name and explicit-bash-args are still non-safe local variables now.

> Best regards, Michael.

-- 
Best Regards
Shuguang Sun