bug#24291: 25.1; display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

bug#24291: 25.1; display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[N. Jackson]

The command display-time-world seems to be ignoring the
zoneinfo-style-world-list variable; instead, the time for the default
list of cities is displayed.

Setting zoneinfo-style-world-list in `emacs -Q' works as expected, so I
bisected my init file and it seems that the problem is "caused" by
setting display-time-mode to show the clock in the mode line.

This recipe shows the problem from `emacs -Q'

0. emacs -Q

1. Enter the following elisp in *scratch*:

  (custom-set-variables
   '(display-time-mode t)
   '(zoneinfo-style-world-list
     (quote
      (("Etc/UTC" "Universal Time")
       ("AST4ADT" "Atlantic Time")
       ("EST5EDT" "Eastern Time")
       ("Europe/London" "London")
       ("Asia/Tokyo" "Tokyo")))))

2. `C-x C-e' (eval-last-sexp) to run it

3. `M-x display-time-world'

Observed result:

  Seattle   Tuesday 23 August 04:22 PDT
  New York  Tuesday 23 August 07:22 EDT
  London    Tuesday 23 August 12:22 BST
  Paris     Tuesday 23 August 13:22 CEST
  Bangalore Tuesday 23 August 16:52 IST
  Tokyo     Tuesday 23 August 20:22 JST

Expected result:

  Universal Time Tuesday 23 August 11:24 UTC
  Atlantic Time  Tuesday 23 August 08:24 ADT
  Eastern Time   Tuesday 23 August 07:24 EDT
  London         Tuesday 23 August 12:24 BST
  Tokyo          Tuesday 23 August 20:24 JST


If the recipe above is modified to remove the line that sets
display-time-mode, the output is as expected.

I'm more than slightly confused by what I'm observing here. I don't
believe it was more than a couple of months ago that I set z-s-w-l for
the first time. It worked perfectly then even though I always have d-t-m
on (because the mode line clock is the one I use to know what time it is
during the day). But now I'm seeing the reported problem in versions of
the Emacs 25 pre-release going back for months, and indeed, in Emacs
24.5.


In GNU Emacs 25.1.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9)
 of 2016-07-24 built on moondust
Windowing system distributor 'Fedora Project', version 11.0.11803000
System Description:	Fedora release 23 (Twenty Three)

Configured using:
 'configure --prefix=/home/nlj/local/ --enable-checking=yes,glyphs
 --enable-check-lisp-object-type 'CFLAGS=-O2 -g3 -gdwarf-4''

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GCONF GSETTINGS NOTIFY
ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LC_MONETARY: en_DK.utf8
  value of $LC_NUMERIC: en_DK.utf8
  value of $LC_TIME: en_DK.utf8
  value of $LANG: en_CA.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix


Features:
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bug#24291: 25.1; display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[Eli Zaretskii]

> From: nljlistbox2@gmail.com (N. Jackson)
> Date: Tue, 23 Aug 2016 08:50:53 -0300
> 
> 0. emacs -Q
> 
> 1. Enter the following elisp in *scratch*:
> 
>   (custom-set-variables
>    '(display-time-mode t)
>    '(zoneinfo-style-world-list
>      (quote
>       (("Etc/UTC" "Universal Time")
>        ("AST4ADT" "Atlantic Time")
>        ("EST5EDT" "Eastern Time")
>        ("Europe/London" "London")
>        ("Asia/Tokyo" "Tokyo")))))
> 
> 2. `C-x C-e' (eval-last-sexp) to run it
> 
> 3. `M-x display-time-world'
> 
> Observed result:
> 
>   Seattle   Tuesday 23 August 04:22 PDT
>   New York  Tuesday 23 August 07:22 EDT
>   London    Tuesday 23 August 12:22 BST
>   Paris     Tuesday 23 August 13:22 CEST
>   Bangalore Tuesday 23 August 16:52 IST
>   Tokyo     Tuesday 23 August 20:22 JST
> 
> Expected result:
> 
>   Universal Time Tuesday 23 August 11:24 UTC
>   Atlantic Time  Tuesday 23 August 08:24 ADT
>   Eastern Time   Tuesday 23 August 07:24 EDT
>   London         Tuesday 23 August 12:24 BST
>   Tokyo          Tuesday 23 August 20:24 JST

You need to set zoneinfo-style-world-list before time.el is loaded.

bug#24291: 25.1; display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[N. Jackson]

At 17:43 +0300 on Tuesday 2016-08-23, Eli Zaretskii wrote:

>> From: nljlistbox2@gmail.com (N. Jackson)
>> Date: Tue, 23 Aug 2016 08:50:53 -0300
>> 
>> 0. emacs -Q
>> 
>> 1. Enter the following elisp in *scratch*:
>> 
>>   (custom-set-variables
>>    '(display-time-mode t)
>>    '(zoneinfo-style-world-list
>>      (quote
>>       (("Etc/UTC" "Universal Time")
>>        ("AST4ADT" "Atlantic Time")
>>        ("EST5EDT" "Eastern Time")
>>        ("Europe/London" "London")
>>        ("Asia/Tokyo" "Tokyo")))))
>> 
>> 2. `C-x C-e' (eval-last-sexp) to run it
>> 
>> 3. `M-x display-time-world'
>> 
>> Observed result:
>> 
>>   Seattle   Tuesday 23 August 04:22 PDT
>>   New York  Tuesday 23 August 07:22 EDT
>>   London    Tuesday 23 August 12:22 BST
>>   Paris     Tuesday 23 August 13:22 CEST
>>   Bangalore Tuesday 23 August 16:52 IST
>>   Tokyo     Tuesday 23 August 20:22 JST
>> 
>> Expected result:
>> 
>>   Universal Time Tuesday 23 August 11:24 UTC
>>   Atlantic Time  Tuesday 23 August 08:24 ADT
>>   Eastern Time   Tuesday 23 August 07:24 EDT
>>   London         Tuesday 23 August 12:24 BST
>>   Tokyo          Tuesday 23 August 20:24 JST
>
> You need to set zoneinfo-style-world-list before time.el is loaded.

I see. Then maybe showing he problem from `emacs -Q' requires a more
carefully-crafted example.

But this doesn't work when I run Emacs normally, and in that case I'm
not doing anything unusual. I don't know when time.el is loaded with
respect to when my init file is run. But even if I comment out my entire
init file except for this snippet, this problem occurs.

I can't change the order because Customize puts its variables in
alphabetical order.

N.

bug#24291: 25.1; display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[Eli Zaretskii]

> From: nljlistbox2@gmail.com (N. Jackson)
> Cc: 24291@debbugs.gnu.org
> Date: Tue, 23 Aug 2016 16:39:21 -0300
> 
> I can't change the order because Customize puts its variables in
> alphabetical order.

You can use setq instead.

bug#24291: 25.1; display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[Glenn Morris]

Sounds like zoneinfo-style-world-list needs a :set function to update
any existing display.

bug#24291: 25.1; display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[N. Jackson]

At 05:38 +0300 on Wednesday 2016-08-24, Eli Zaretskii wrote:

>> From: nljlistbox2@gmail.com (N. Jackson)
>> Cc: 24291@debbugs.gnu.org
>> Date: Tue, 23 Aug 2016 16:39:21 -0300
>> 
>> I can't change the order because Customize puts its variables in
>> alphabetical order.
>
> You can use setq instead.

Hi Eli,

I'm not clear what you're telling me here.

If you're saying that there is a workaround available to me, then thank
you. Yes, indeed setq works.

If you are saying that there is no problem because the user can use
setq instead of using Customize, then I think I disagree. To me it
doesn't make sense for Emacs to have a variable that is "Customizable"
if using Customize to set it doesn't work reliably.

N.

bug#24291: 25.1; display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[Eli Zaretskii]

> From: nljlistbox2@gmail.com (N. Jackson)
> Cc: 24291@debbugs.gnu.org
> Date: Wed, 24 Aug 2016 18:03:03 -0300
> 
> At 05:38 +0300 on Wednesday 2016-08-24, Eli Zaretskii wrote:
> 
> >> From: nljlistbox2@gmail.com (N. Jackson)
> >> Cc: 24291@debbugs.gnu.org
> >> Date: Tue, 23 Aug 2016 16:39:21 -0300
> >> 
> >> I can't change the order because Customize puts its variables in
> >> alphabetical order.
> >
> > You can use setq instead.
> 
> Hi Eli,
> 
> I'm not clear what you're telling me here.
> 
> If you're saying that there is a workaround available to me, then thank
> you. Yes, indeed setq works.
> 
> If you are saying that there is no problem because the user can use
> setq instead of using Customize, then I think I disagree. To me it
> doesn't make sense for Emacs to have a variable that is "Customizable"
> if using Customize to set it doesn't work reliably.

Knowing me and my attitude towards Emacs, what do you think I'm
saying?

bug#24291: display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[Paul Eggert]

[-- Attachment #1: Type: text/plain, Size: 171 bytes --]

This seems to be a clear bug in time.el, as a customizable variable's initial 
value should not depend on that of another customizable variable. Proposed patch 
attached.

[-- Attachment #2: 0001-Fix-customization-of-zoneinfo-style-world-list.patch --]
[-- Type: text/x-patch, Size: 3664 bytes --]

From 59ad540379c79271c373c1556d38f67aa13944e6 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@day>
Date: Mon, 2 Oct 2017 00:05:47 -0700
Subject: [PATCH] Fix customization of zoneinfo-style-world-list

A customizable variable's initial value cannot depend on that of
another customizable variable, since the variables are initialized
in other than textual order.  Problem reported by N. Jackson
(Bug#24291).
* lisp/time.el (display-time-world-list): Default to t,
a special value that expands to zoneinfo-style-word-list
if that works, and to legacy-style-word-list otherwise.
(time--display-world-list): New function.
(display-time-world, display-time-world-timer): Use it.
---
 lisp/time.el | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/lisp/time.el b/lisp/time.el
index 5c0eac0..c8726a9 100644
--- a/lisp/time.el
+++ b/lisp/time.el
@@ -160,24 +160,33 @@ legacy-style-world-list
   :type '(repeat (list string string))
   :version "23.1")
 
-(defcustom display-time-world-list
-  ;; Determine if zoneinfo style timezones are supported by testing that
-  ;; America/New York and Europe/London return different timezones.
-  (let ((nyt (format-time-string "%z" nil "America/New_York"))
-        (gmt (format-time-string "%z" nil "Europe/London")))
-    (if (string-equal nyt gmt)
-        legacy-style-world-list
-      zoneinfo-style-world-list))
+(defcustom display-time-world-list t
   "Alist of time zones and places for `display-time-world' to display.
 Each element has the form (TIMEZONE LABEL).
 TIMEZONE should be in a format supported by your system.  See the
 documentation of `zoneinfo-style-world-list' and
 `legacy-style-world-list' for two widely used formats.  LABEL is
-a string to display as the label of that TIMEZONE's time."
+a string to display as the label of that TIMEZONE's time.
+
+If the value is t instead of an alist, use the value of
+`zoneinfo-style-world-list' if it works on this platform, and of
+`legacy-style-world-list' otherwise."
+
   :group 'display-time
   :type '(repeat (list string string))
   :version "23.1")
 
+(defun time--display-world-list ()
+  (if (listp display-time-world-list)
+      display-time-world-list
+    ;; Determine if zoneinfo style timezones are supported by testing that
+    ;; America/New York and Europe/London return different timezones.
+    (let ((nyt (format-time-string "%z" nil "America/New_York"))
+	  (gmt (format-time-string "%z" nil "Europe/London")))
+      (if (string-equal nyt gmt)
+	  legacy-style-world-list
+	zoneinfo-style-world-list))))
+
 (defcustom display-time-world-time-format "%A %d %B %R %Z"
   "Format of the time displayed, see `format-time-string'."
   :group 'display-time
@@ -548,7 +557,7 @@ display-time-world
              (not (get-buffer display-time-world-buffer-name)))
     (run-at-time t display-time-world-timer-second 'display-time-world-timer))
   (with-current-buffer (get-buffer-create display-time-world-buffer-name)
-    (display-time-world-display display-time-world-list)
+    (display-time-world-display (time--display-world-list))
     (display-buffer display-time-world-buffer-name
 		    (cons nil '((window-height . fit-window-to-buffer))))
     (display-time-world-mode)))
@@ -556,7 +565,7 @@ display-time-world
 (defun display-time-world-timer ()
   (if (get-buffer display-time-world-buffer-name)
       (with-current-buffer (get-buffer display-time-world-buffer-name)
-        (display-time-world-display display-time-world-list))
+        (display-time-world-display (time--display-world-list)))
     ;; cancel timer
     (let ((list timer-list))
       (while list
-- 
2.7.4

bug#24291: display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[Eli Zaretskii]

> Cc: 24291@debbugs.gnu.org, Eli Zaretskii <eliz@gnu.org>
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Mon, 2 Oct 2017 00:10:09 -0700
> 
> This seems to be a clear bug in time.el, as a customizable variable's initial 
> value should not depend on that of another customizable variable. Proposed patch 
> attached.

LGTM, thanks.

bug#24291: display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[Paul Eggert]

OK, I installed it on emacs-26 and am closing the bug.

bug#24291: display-time-world seems to ignore zoneinfo-style-world-list when display-time-mode is t

[N. Jackson]

Hello Paul,

At 00:10 -0700 on Monday 2017-10-02, Paul Eggert wrote:
>
> This seems to be a clear bug in time.el, as a customizable
> variable's initial value should not depend on that of another
> customizable variable. Proposed patch attached.

I have just tested your proposed patch, and it fixes the problem
here.

(I'm on a recent version of the emacs-26 branch:

In GNU Emacs 26.0.60 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.17)
 of 2017-10-02 built on moondust.localdomain
Repository revision: 8b2ab5014b2c1641bb62efa63b9ee54b4c056b5a
Windowing system distributor 'Fedora Project', version 11.0.11903000
System Description:	Fedora release 25 (Twenty Five)

.)

Thank you.

N.