bug#25506: 26.0.50; Buffer-menu-bury gets (void-variable tabulated-list--near-rows)

[Tino Calancha]

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

> Bob Rogers <rogers@modulargenetics.com> writes:
>
>>    This has been happening for a while now in master, but not in the
>> 25.1 release.  To reproduce:
>>
>>    1.  emacs -Q
>>
>>    2.  "C-x C-b" (which shows the buffer menu with *scratch* and
>> *Messages* in a new window), and "C-x o" (which moves the cursor into
>> this window in front of *scratch*).
>>
>>    3.  "b" to invoke Buffer-menu-bury.  The line with the *scratch*
>> buffer should move below *Messages*; instead, it is erased and only
>> partly redrawn in the new location, and the error message "Symbol s
>> value as variable is void: tabulated-list--near-rows" is displayed.
> Thank you very much for report this bug!
> Such `tabulated-list--near-rows' must be bound before
> a call to `tabulated-list-print-col', because the latter use the former
> via `tabulated-list--col-local-max-widths'.
>>    The patch below restores the expected behavior, but it's a kludge to
>> require buff-menu.el to know so much about tabulated-list.el innards.
> I agree with you.  The variable `tabulated-list--near-rows' is intended
> just for internal use in tabulated-list.el.
> I am going to apply the following patch:
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>>From ade0652cc2a7103cd910accda8165ff8ee7c719f Mon Sep 17 00:00:00 2001
> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Sun, 22 Jan 2017 14:23:45 +0900
> Subject: [PATCH] Prevent to use tabulated-list--near-rows unbound
>
> * lisp/emacs-lisp/tabulated-list.el (tabulated-list-print-entry):
> Make sure 'tabulated-list--near-rows' is bound before use it (Bug#25506).
> ---
>  lisp/emacs-lisp/tabulated-list.el | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/lisp/emacs-lisp/tabulated-list.el 
> b/lisp/emacs-lisp/tabulated-list.el
> index eadf79ffd4..b6b49b1bfa 100644
> --- a/lisp/emacs-lisp/tabulated-list.el
> +++ b/lisp/emacs-lisp/tabulated-list.el
> @@ -412,8 +412,13 @@ tabulated-list-print-entry
>       (inhibit-read-only t))
>      (if (> tabulated-list-padding 0)
>       (insert (make-string x ?\s)))
> -    (dotimes (n ncols)
> -      (setq x (tabulated-list-print-col n (aref cols n) x)))
> +    (let ((tabulated-list--near-rows ; Bind it if not bound yet (Bug#25506).
> +           (or (bound-and-true-p tabulated-list--near-rows)
> +               (list (or (tabulated-list-get-entry (point-at-bol 0))
> +                         cols)
> +                     cols))))
> +      (dotimes (n ncols)
> +        (setq x (tabulated-list-print-col n (aref cols n) x))))
>      (insert ?\n)
>      ;; Ever so slightly faster than calling `put-text-property' twice.
>      (add-text-properties
Pushed to master branch as commit ade0652cc2a7103cd910accda8165ff8ee7c719f