bug#66700: 30.0.50; Some history is missing with multiple eshell buffers

[Sean Whitton <spwhitton@spwhitton.name>]

On Thu 16 Nov 2023 at 05:47pm +08, Liu Hui wrote:

> Jim Porter <jporterbugs@gmail.com> 于2023年11月15日周三 01:15写道：
>>
>> On 11/14/2023 4:43 AM, Sean Whitton wrote:
>> > On Tue 14 Nov 2023 at 02:32pm +02, Eli Zaretskii wrote:
>> >>
>> >> IMO, this is too soon to change the default behavior in incompatible
>> >> ways.  We need to wait for a while, perhaps at least one major
>> >> release, before we do that.
>> >
>> > This is fair enough.  It would be really useful to have the default
>> > behaviour now for those of used to it from other shells, though -- Liu,
>> > perhaps you would be interested in adding a defcustom?
>>
>> Yeah, I think a defcustom would be good here. That would also make it
>> easier for us to test out the new code and find any bugs.
>
> Thank you all for your suggestions. A defcustom has been added in the
> attached patch without changing previous behavior.

Thanks.  This looks good, but can you add a NEWS entry, please?

Ideally it would also get documented in the Eshell manual.

> From e2cd3a9d28b35806d4e6a83e98f0dc25550651e2 Mon Sep 17 00:00:00 2001
> From: Liu Hui <liuhui1610@gmail.com>
> Date: Thu, 16 Nov 2023 11:45:28 +0800
> Subject: [PATCH] Add option `eshell-history-append'
>
> * lisp/eshell/em-hist.el (eshell-history-append): New option.
> (eshell--save-history): New function.
> (eshell-hist-initialize):
> (eshell-save-some-history): Replace eshell-write-history with
> eshell--save-history, which respects the new option.
> ---
>  lisp/eshell/em-hist.el | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/lisp/eshell/em-hist.el b/lisp/eshell/em-hist.el
> index cf03f8399a6..79336204847 100644
> --- a/lisp/eshell/em-hist.el
> +++ b/lisp/eshell/em-hist.el
> @@ -116,6 +116,12 @@ eshell-save-history-on-exit
>  		 (const :tag "Ask" ask)
>  		 (const :tag "Always save" t)))
>  
> +(defcustom eshell-history-append nil
> +  "If non-nil, append new entries to the history file when saving history."
> +  :type '(choice (const :tag "Overwrite history file" nil)
> +		 (const :tag "Append new entries to file" t))
> +  :version "30.1")
> +
>  (defcustom eshell-input-filter 'eshell-input-filter-default
>    "Predicate for filtering additions to input history.
>  Takes one argument, the input.  If non-nil, the input may be saved on
> @@ -294,17 +300,21 @@ eshell-hist-initialize
>      (if eshell-history-file-name
>  	(eshell-read-history nil t))
>  
> -    (add-hook 'eshell-exit-hook #'eshell-write-history nil t))
> +    (add-hook 'eshell-exit-hook #'eshell--save-history nil t))
>  
>    (unless eshell-history-ring
>      (setq eshell-history-ring (make-ring eshell-history-size)))
>  
> -  (add-hook 'eshell-exit-hook #'eshell-write-history nil t)
> +  (add-hook 'eshell-exit-hook #'eshell--save-history nil t)
>  
>    (add-hook 'kill-emacs-query-functions #'eshell-save-some-history)
>  
>    (add-hook 'eshell-input-filter-functions #'eshell-add-to-history nil t))
>  
> +(defun eshell--save-history ()
> +  "Save the history for current Eshell buffer."
> +  (eshell-write-history nil eshell-history-append))
> +
>  (defun eshell-save-some-history ()
>    "Save the history for any open Eshell buffers."
>    (dolist (buf (buffer-list))
> @@ -318,7 +328,7 @@ eshell-save-some-history
>  			(format-message
>  			 "Save input history for Eshell buffer `%s'? "
>  			 (buffer-name buf)))))
> -	      (eshell-write-history)))))
> +	      (eshell--save-history)))))
>    t)
>  
>  (defun eshell/history (&rest args)

-- 
Sean Whitton