bug#29462: 24.4; eval-when-compile won't mute warning as says in info doc

bug#29462: 24.4; eval-when-compile won't mute warning as says in info doc

[Emanuel Berg]

In (info "(elisp) Warning Tips"), it says

   * If you use many functions and variables
     from a certain file, you can add
     a ‘require’ for that package to avoid
     compilation warnings for them.
     For instance,

          (eval-when-compile
            (require 'foo))

However that won't mute the warnings.
Using (eval-when-compile (require 'cl-lib)) it says

    In end of data:
    wrap-search-cp.el:133:1:Warning: the
    function `cl-find-if' might not be defined
    at runtime.

Perhaps that should be `eval-and-compile', or
plain `require'?



In GNU Emacs 24.4.1 (arm-unknown-linux-gnueabihf, GTK+ Version 3.14.5)
 of 2015-03-10 on bm-wb-01, modified by Debian
System Description:	Raspbian GNU/Linux 8.0 (jessie)

Configured using:
 `configure --build arm-linux-gnueabihf
 --prefix=/usr --sharedstatedir=/var/lib
 --libexecdir=/usr/lib --localstatedir=/var/lib
 --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
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 --build arm-linux-gnueabihf --prefix=/usr
 --sharedstatedir=/var/lib
 --libexecdir=/usr/lib --localstatedir=/var/lib
 --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.4/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.4/site-lisp:/usr/share/emacs/site-lisp
 --with-x=yes --with-x-toolkit=gtk3
 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -fstack-protector-strong -Wformat
 -Werror=format-security -Wall'
 CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-z,relro'

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

Major mode: Summary

Minor modes in effect:
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C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
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C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-@ C-n C-n 
C-n C-n C-n C-p C-n C-p C-e ESC w ဃ ESC o ESC o ESC 
o ESC p ESC o ESC x C-g ESC o ESC o ESC p ESC x r e 
p - DEL o r t - b u g RET

Recent messages:
Follow the link
(error "No buttons or fields found") in widget-move
Follow the link [4 times]
mouse-2: hide the MIME part; down-mouse-3: more options
No hit.
Saving file /home/incal/.newsrc-dribble...
Wrote /home/incal/.newsrc-dribble [2 times]
(user-error "No such node or anchor: Tisp") in user-error
nil
Mark set [2 times]

Load-path shadows:
/usr/share/emacs/24.4/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup
~/.emacs.d/emacs-init/misc hides /usr/share/emacs/24.4/lisp/misc
/usr/share/emacs24/site-lisp/flim/md4 hides /usr/share/emacs/24.4/lisp/md4
/usr/share/emacs24/site-lisp/flim/hex-util hides /usr/share/emacs/24.4/lisp/hex-util
~/.emacs.d/lisp/abbrev hides /usr/share/emacs/24.4/lisp/abbrev
~/.emacs.d/emacs-init/gnus/server hides /usr/share/emacs/24.4/lisp/server
/usr/share/emacs24/site-lisp/dictionaries-common/ispell hides /usr/share/emacs/24.4/lisp/textmodes/ispell
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/usr/share/emacs24/site-lisp/flim/sasl-ntlm hides /usr/share/emacs/24.4/lisp/net/sasl-ntlm
/usr/share/emacs24/site-lisp/flim/sasl-cram hides /usr/share/emacs/24.4/lisp/net/sasl-cram
/usr/share/emacs24/site-lisp/flim/ntlm hides /usr/share/emacs/24.4/lisp/net/ntlm
/usr/share/emacs24/site-lisp/flim/sasl hides /usr/share/emacs/24.4/lisp/net/sasl
/usr/share/emacs24/site-lisp/flim/hmac-def hides /usr/share/emacs/24.4/lisp/net/hmac-def
/usr/share/emacs24/site-lisp/flim/hmac-md5 hides /usr/share/emacs/24.4/lisp/net/hmac-md5
/usr/share/emacs24/site-lisp/flim/sasl-digest hides /usr/share/emacs/24.4/lisp/net/sasl-digest

Features:
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dig mailcap gnus-sum nnoo gnus-group gnus-undo
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nnheader mail-utils info slime-autoloads
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Memory information:
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 (buffers 512 36)
 (heap 1024 30760 9225))

-- 
underground experts united
http://user.it.uu.se/~embe8573

bug#29462: 24.4; eval-when-compile won't mute warning as says in info doc

[Michael Heerdegen]

Emanuel Berg <moasen@zoho.com> writes:

> In (info "(elisp) Warning Tips"), it says
>
>    * If you use many functions and variables
>      from a certain file, you can add
>      a ‘require’ for that package to avoid
>      compilation warnings for them.
>      For instance,
>
>           (eval-when-compile
>             (require 'foo))

Thanks for the report.

I find this whole sentence confusing and misleading in general.  The
main purpose of `require' is not to silence warnings, and calling it is
very often something needed, not only something one "can" do.


Michael.

bug#29462: 24.4; eval-when-compile won't mute warning as says in info doc

[Emanuel Berg]

Michael Heerdegen wrote:

>> In (info "(elisp) Warning Tips"), it says *
>> If you use many functions and variables from
>> a certain file, you can add a ‘require’ for
>> that package to avoid compilation warnings
>> for them. For instance, (eval-when-compile
>> (require 'foo))
>
> Thanks for the report.
>
> I find this whole sentence confusing and
> misleading in general. The main purpose of
> `require' is not to silence warnings

It sure send mixed signals and as it stands one
gets the impression what you should do is find
ways of silencing warnings, instead of
improving the code so there is nothing to warn
about to begin with.

-- 
underground experts united
http://user.it.uu.se/~embe8573

bug#29462: 24.4; eval-when-compile won't mute warning as says in info doc

[Eli Zaretskii]

> From: Emanuel Berg <moasen@zoho.com>
> Date: Mon, 27 Nov 2017 03:49:42 +0100
> 
> It sure send mixed signals and as it stands one
> gets the impression what you should do is find
> ways of silencing warnings, instead of
> improving the code so there is nothing to warn
> about to begin with.

In many real-life situations, there's no cleaner way of avoiding such
warnings, except to require the package which defines the features you
are warned about.  There's nothing wrong about doing that, which is
why you will find such uses all over the Emacs sources.

bug#29462: 24.4; eval-when-compile won't mute warning as says in info doc

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Date: Mon, 27 Nov 2017 03:44:46 +0100
> 
> Emanuel Berg <moasen@zoho.com> writes:
> 
> > In (info "(elisp) Warning Tips"), it says
> >
> >    * If you use many functions and variables
> >      from a certain file, you can add
> >      a ‘require’ for that package to avoid
> >      compilation warnings for them.
> >      For instance,
> >
> >           (eval-when-compile
> >             (require 'foo))
> 
> Thanks for the report.
> 
> I find this whole sentence confusing and misleading in general.  The
> main purpose of `require' is not to silence warnings, and calling it is
> very often something needed, not only something one "can" do.

The above citation is from a section which explains how to avoid
warnings.  It is not the place where we document 'require' itself,
only its use to avoid warnings.  So reading that out of context as a
statement of the main purpose of 'require' is a mistake, as 'require'
is fully documented elsewhere in the manual.

In the context of avoiding warnings, I see no problem in mentioning
'require'.

bug#29462: 24.4; eval-when-compile won't mute warning as says in info doc

[Eli Zaretskii]

> From: Emanuel Berg <moasen@zoho.com>
> Date: Mon, 27 Nov 2017 02:21:53 +0100
> 
> 
> In (info "(elisp) Warning Tips"), it says
> 
>    * If you use many functions and variables
>      from a certain file, you can add
>      a ‘require’ for that package to avoid
>      compilation warnings for them.
>      For instance,
> 
>           (eval-when-compile
>             (require 'foo))
> 
> However that won't mute the warnings.
> Using (eval-when-compile (require 'cl-lib)) it says
> 
>     In end of data:
>     wrap-search-cp.el:133:1:Warning: the
>     function `cl-find-if' might not be defined
>     at runtime.

Thanks, fixed.