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

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

[Bob Rogers]

   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.

   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.

					-- Bob Rogers
					   http://www.rgrjr.com/

------------------------------------------------------------------------
diff --git a/lisp/buff-menu.el b/lisp/buff-menu.el
index 77b325f..27a00b9 100644
--- a/lisp/buff-menu.el
+++ b/lisp/buff-menu.el
@@ -595,7 +595,10 @@ Buffer-menu-bury
 	   (save-excursion
 	     (let ((elt (tabulated-list-delete-entry)))
 	       (goto-char (point-max))
-	       (apply 'tabulated-list-print-entry elt)))
+               (let ((tabulated-list--near-rows
+                       (list
+                         (tabulated-list-get-entry (point-at-bol 0)))))
+                 (apply 'tabulated-list-print-entry elt))))
 	   (message "Buffer buried."))
 	  (t
 	   (tabulated-list-delete-entry)
------------------------------------------------------------------------
In GNU Emacs 26.0.50.1 (x86_64-suse-linux-gnu, GTK+ Version 2.24.31)
 of 2017-01-21 built on orion
Repository revision: 07d15164271270d09464863d7ec2bfce62d65085
Windowing system distributor 'The X.Org Foundation', version 11.0.11601000
System Description:	openSUSE 13.2 (Harlequin) (x86_64)

Recent messages:
Read-Only mode disabled in current buffer
Mark set
Buffer-menu-bury
Buffer buried. [6 times]
Mark set
Auto-saving...
Undo! [14 times]
user-error: No further undo information
Buffer buried. [2 times]
Making completion list... [2 times]

Configured using:
 'configure --without-dbus --without-gsettings --without-gconf'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY GNUTLS FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS GTK2 X11

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Emacs-Lisp

Minor modes in effect:
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/usr/share/emacs/site-lisp/site-start hides /usr/local/share/emacs/site-lisp/site-start
/home/rogers/emacs/imported/loaddefs hides /usr/local/share/emacs/26.0.50/lisp/loaddefs

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

[Tino Calancha]

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
-- 
2.11.0

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
In GNU Emacs 26.0.50.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.6)
 of 2017-01-
Repository revision: ad29e145b16cf2966e3a9df884cbc234f1ae3e51

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