Subject: 25.2; shell-mode over TRAMP does not read remote history file as comint input ring
From: Fan Yang <[email-masked]>
To: [email-masked]
Date: Sat, 20 Jul 2019 22:30:42 +0800 (CST)
List-Id: <debbugs-submit.debbugs.gnu.org>

* Bug description:

When using "M-x shell" on a remote file (say "/scp:yf@val17:"), a bash
is started at the server "val17" as the user "yf".  But the "*shell*"
buffer is started with an empty input ring.  It does not read bash
history file ("/scp:yf@val17:~/.bash_history") into comint input ring.

* What is expected:

When using "M-x shell" on a remote file (say "/scp:yf@val17:"), a bash
is started at the server "val17" as the user "yf".  The "*shell*"
1. has the content of "/scp:yf@val17:~/.bash_history" as comint input
   ring.  And I can use "M-p" to insert previous command, use "M-r" to
   isearch previous comamnd, etc.
2. the commands I have input in this "*shell*" will be appended to
   "/scp:yf@val17:~/.bash_history" after shell exit.
Just like what "shell-mode" does for local shell.

* To re-produce:

Here is the content of the dribble file of my re-producing this issue
(control characters are replaced with caret)

--8<---------------cut here---------------start------------->8---
^X^F/scp:yf@val17:
^[xshell

^[p^[p^[p^X^Cyes
--8<---------------cut here---------------end--------------->8---

* My findings, if I may:

The code of shell-mode shows

--8<---------------cut here---------------start------------->8---
      (setq comint-input-ring-file-name
	    (or (getenv "HISTFILE")
		(cond ((string-equal shell "bash") "~/.bash_history")
		      ((string-equal shell "ksh") "~/.sh_history")
		      (t "~/.history"))))
--8<---------------cut here---------------end--------------->8---

It seems remote file path is not considered.

* How big this issue is?

Have a shell history is convenient and saves a lot of typing repeated or
similar commands.  Me and many of my colleagues use shell history
isearch heavily.  It works very well for local shells.  It is a little
bit disappointing that it does not work on remote shells.

Best Regards,
Fan

In GNU Emacs 25.2.2 (x86_64-pc-linux-gnu, GTK+ Version 3.22.21)
 of 2017-09-23, modified by Debian built on lgw01-amd64-050
System Description:	Ubuntu 18.04.2 LTS

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