bug#15661: 24.3.50; calendar.el broken

bug#15661: 24.3.50; calendar.el broken

[Andreas Röhler]

M-x diary-view-entries RET

fails saying:

Symbol's value as variable is void: displayed-month

AFAIU reason is new defvar behavior, which breaks legacy code.

calendar.el has a

(defvar displayed-month)

which doesn't longer intialise to nil.

There must be a lot of things be broken that way.

Please consider reverting that change to defvar.
Maybe signaling lexical scope with a buffer-local variable might do the job and make me happy again? ;)

Cheers,

Andreas

In GNU Emacs 24.3.50.1 (i686-pc-linux-gnu, GTK+ Version 2.24.10)
  of 2013-08-28 on purzel.sitgens
Windowing system distributor `The X.Org Foundation', version 11.0.11203000
System Description:	openSUSE 12.2 (i586)

Configured using:
  `configure 'CFLAGS=-g -O''

Important settings:
   value of $LANG: de_DE.UTF-8
   value of $XMODIFIERS: @im=local
   locale-coding-system: utf-8-unix
   default enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
   shell-dirtrack-mode: t
   tooltip-mode: t
   mouse-wheel-mode: t
   tool-bar-mode: t
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   file-name-shadow-mode: t
   global-font-lock-mode: t
   font-lock-mode: t
   blink-cursor-mode: t
   auto-composition-mode: t
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   auto-compression-mode: t
   line-number-mode: t
   transient-mark-mode: t

Recent input:
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<menu-bar> <options> <menu-set-font> <help-echo> <help-echo>
C-x C-f <M-backspace> <M-backspace> 2 0 1 3 1 0 2 0
<tab> l i a s <tab> <backspace> <backspace> s o <backspace>
p <tab> c a l e <tab> c a l e <tab> <return> M-x e
v a l - b u <tab> <return> <help-echo> <help-echo>
<help-echo> <help-echo> M-x h s <backspace> <backspace>
s h e l l <return> c d <return> > SPC d i a r y <return>
l a <backspace> s SPC - l a r t <return> C-x b <return>
M-x d i r a <backspace> <backspace> a r y - v i e w
<tab> e n t r <tab> <return> M-x r e p o r t - e m
a c s . <backspace> - b u <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
~
%: Symbol's value as variable is void: displayed-month

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bug#15661: 24.3.50; calendar.el broken

[Alan Mackenzie]

Andreas R?hler <andreas.roehler@easy-emacs.de> wrote:
> M-x diary-view-entries RET

> fails saying:

> Symbol's value as variable is void: displayed-month

> AFAIU reason is new defvar behavior, which breaks legacy code.

> calendar.el has a

> (defvar displayed-month)

> which doesn't longer intialise to nil.

I'm not sure it ever did.  At least as far back as Emacs 21, not
specifying an initial value leaves the variable unbound.

> There must be a lot of things be broken that way.

I think I agree with this, though, having fallen into this trap several
times.  ;-)

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#15661: 24.3.50; calendar.el broken

[Glenn Morris]

Andreas Röhler wrote:

> M-x diary-view-entries RET
>
> fails saying:
>
> Symbol's value as variable is void: displayed-month

Works fine here. Recipe from emacs -Q?

> AFAIU reason is new defvar behavior, which breaks legacy code.

No. Please desist from the usual wide-eyed speculation.

> calendar.el has a
>
> (defvar displayed-month)

Since over 5 years ago.

bug#15661: 24.3.50; calendar.el broken

[Andreas Röhler]

Am 20.10.2013 20:13, schrieb Glenn Morris:
> Andreas Röhler wrote:
>
>> M-x diary-view-entries RET
>>
>> fails saying:
>>
>> Symbol's value as variable is void: displayed-month
>
> Works fine here. Recipe from emacs -Q?
>

Yes, started from emacs -Q
Also got it from openSuse 12.3

bug#15661: 24.3.50; calendar.el broken

[Thierry Volpiatto]

Andreas Röhler <andreas.roehler@easy-emacs.de> writes:

> Am 20.10.2013 20:13, schrieb Glenn Morris:
>> Andreas Röhler wrote:
>>
>>> M-x diary-view-entries RET
>>>
>>> fails saying:
>>>
>>> Symbol's value as variable is void: displayed-month
>>
>> Works fine here. Recipe from emacs -Q?
>>
>
> Yes, started from emacs -Q
> Also got it from openSuse 12.3

displayed-month among others is make local-var in calendar buffer, so if
you call the function from there (d), it will work as expected,
otherwise the var(s) is/are unknown(s).

-- 
Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997 

bug#15661: 24.3.50; calendar.el broken

[Andreas Röhler]

Am 21.10.2013 09:47, schrieb Thierry Volpiatto:
> Andreas Röhler <andreas.roehler@easy-emacs.de> writes:
>
>> Am 20.10.2013 20:13, schrieb Glenn Morris:
>>> Andreas Röhler wrote:
>>>
>>>> M-x diary-view-entries RET
>>>>
>>>> fails saying:
>>>>
>>>> Symbol's value as variable is void: displayed-month
>>>
>>> Works fine here. Recipe from emacs -Q?
>>>
>>
>> Yes, started from emacs -Q
>> Also got it from openSuse 12.3
>
> displayed-month among others is make local-var in calendar buffer,

By the mode itself, which looks wrong, as libraries outside like diary seem to make use of it also.

  so if
> you call the function from there (d), it will work as expected,
> otherwise the var(s) is/are unknown(s).
>

Get this error also from

M-x diary-view-other-diary-entries RET

while

M-x diary-show-all-entries RET

works

;;;;;;;;

Seeing inside calendar.el

(unless (boundp 'displayed-month) (setq displayed-month 1))

which doesn't look recommended.

IIUC

(defvar displayed-month 1)

should DTRT.

bug#15661: 24.3.50; calendar.el broken

[Thierry Volpiatto]

Andreas Röhler <andreas.roehler@easy-emacs.de> writes:

> Am 21.10.2013 09:47, schrieb Thierry Volpiatto:
>> Andreas Röhler <andreas.roehler@easy-emacs.de> writes:
>>
>>> Am 20.10.2013 20:13, schrieb Glenn Morris:
>>>> Andreas Röhler wrote:
>>>>
>>>>> M-x diary-view-entries RET
>>>>>
>>>>> fails saying:
>>>>>
>>>>> Symbol's value as variable is void: displayed-month
>>>>
>>>> Works fine here. Recipe from emacs -Q?
>>>>
>>>
>>> Yes, started from emacs -Q
>>> Also got it from openSuse 12.3
>>
>> displayed-month among others is make local-var in calendar buffer,
>
> By the mode itself, which looks wrong,

Sure it is.

> as libraries outside like diary seem to make use of it also.
>
>  so if
>> you call the function from there (d), it will work as expected,
>> otherwise the var(s) is/are unknown(s).
>>
>
> Get this error also from
>
> M-x diary-view-other-diary-entries RET
>
> while
>
> M-x diary-show-all-entries RET
>
> works
>
> ;;;;;;;;
>
> Seeing inside calendar.el
>
> (unless (boundp 'displayed-month) (setq displayed-month 1))
>
> which doesn't look recommended.
>
> IIUC
>
> (defvar displayed-month 1)
>
> should DTRT.

The right thing should be to remove all these vars and reimplement the code
properly.

-- 
Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997 

bug#15661: 24.3.50; calendar.el broken

[Stefan Monnier]

> I'm not sure it ever did.  At least as far back as Emacs 21, not
> specifying an initial value leaves the variable unbound.

I don't have an Emacs-18 at hand, but this behavior goes back at least
to Emacs-19.34 ;-)


        Stefan

bug#15661: 24.3.50; calendar.el broken

[Glenn Morris]

Andreas Röhler wrote:

>> Works fine here. Recipe from emacs -Q?
>>
>
> Yes, started from emacs -Q
> Also got it from openSuse 12.3

(That's not a recipe starting from emacs -Q.)
You have to call this function from the calendar.
That's the whole point of this function.
It's been like that for as long as this function has existed.

bug#15661: 24.3.50; calendar.el broken

[Andreas Röhler]

Am 21.10.2013 15:14, schrieb Stefan Monnier:
>> I'm not sure it ever did.  At least as far back as Emacs 21, not
>> specifying an initial value leaves the variable unbound.
>
> I don't have an Emacs-18 at hand, but this behavior goes back at least
> to Emacs-19.34 ;-)
>
>
>          Stefan
>
>
>
>

Which shouldn't be an argument by themselves to not clean up.
Suggest re-openening.

bug#15661: 24.3.50; calendar.el broken

[Stefan Monnier]

> Which shouldn't be an argument by themselves to not clean up.

There's no "cleanup" needed.  It would be a major error and introduce
many bugs if we changed (defvar foo) to actually set `foo' to nil if
it's currently unbound.  And it wouldn't even patch up your problem
(since calendar wants a number rather than nil in displayed-month).

> Suggest re-openening.

IIUC your bug report was not about defvar.  You just mislead us there.
Instead, the report was about M-x diary-view-entries RET not working
from a buffer other than *Calendar*.  So, if you want to re-open this
bug (which you can do yourself), please explain why you want it to work
from other buffers, and which behavior you'd expect in that case
(e.g. which days of the diary should be displayed).


        Stefan

bug#15661: 24.3.50; calendar.el broken

[Glenn Morris]

Andreas Röhler wrote:

> Suggest re-openening.

I suggest reading a tutorial on "how to make a good bug report".
You can easily find several with a web search.

bug#15661: 24.3.50; calendar.el broken

[Thierry Volpiatto]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> IIUC your bug report was not about defvar.  You just mislead us there.
> Instead, the report was about M-x diary-view-entries RET not working
> from a buffer other than *Calendar*.

It is a general problem in Emacs with interactive functions present in
M-x and failing because they are out of context.
`diary-view-entries' is a good example.
Probably you could reduce a lot bug reports like this by sending a
meaningful error message in this case.

Actually:

diary-view-entries: Symbol's value as variable is void: displayed-month

is probably clear for you but not for the user.

-- 
Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997