GNU bug report logs - #11928
Spurious bytecomp warning "reference to free variable" when variable defined in required library without an initvalue

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Michael Hoffman <fklv2wf02 <at> sneakemail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: Spurious bytecomp warning "reference to free variable" when variable
	defined in required library without an initvalue
Date: Thu, 12 Jul 2012 18:47:43 -0700

This bug report will be sent to the Bug-GNU-Emacs mailing list
and the GNU bug tracker at debbugs.gnu.org.  Please check that
the From: line contains a valid email address.  After a delay of up
to one day, you should receive an acknowledgement at that address.

Please write in English if possible, as the Emacs maintainers
usually do not have translators for other languages.

Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

====
cat > outer.el << EOF
(eval-when-compile (add-to-list 'load-path ".")
                   (require 'inner))

(defun my-function ()
  inner-a
  inner-b)
EOF

cat > inner.el << EOF
(defvar inner-a)
(defvar inner-b t)

(provide 'inner)
EOF

emacs -Q -batch -f batch-byte-compile outer.el
====

This produces:

====
In my-function:
outer.el:5:3:Warning: reference to free variable `inner-a'
Wrote /net/noble/vol2/home/mmh1/src/experimental/bytecode2/outer.elc
====

I expected there to be no warning, as there is no warning for the
reference of inner-b, which has an initvalue (t).

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please include the output from the following gdb commands:
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In GNU Emacs 24.1.2 (x86_64-unknown-linux-gnu, GTK+ Version 2.18.9)
 of 2012-06-21 on rhel6-x64.grid.gs.washington.edu
Windowing system distributor `Red Hat, Inc.', version 11.0.11004000
Configured using:
 `configure '--without-gif' '--with-x' '--with-x-toolkit=gtk'
 '--prefix=/net/gs/vol3/software/modules-sw/emacs/24.1/Linux/RHEL6/x86_64'
 'LDFLAGS=-L/net/gs/vol3/software/modules-sw/boost/1.45.0/Linux/RHEL6/x86_64/lib/
 -L/net/gs/vol3/software/modules-sw/R/2.9.0/Linux/RHEL6/x86_64/lib/'
 'CPPFLAGS=-I/net/gs/vol3/software/modules-sw/boost/1.45.0/Linux/RHEL6/x86_64/include/
 -I/net/gs/vol3/software/modules-sw/R/2.9.0/Linux/RHEL6/x86_64/include/''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: en_US
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: iso-latin-1-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

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  font-lock-mode: t
  blink-cursor-mode: t
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  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

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Message #8 received at 11928 <at> debbugs.gnu.org (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: Michael Hoffman <fklv2wf02 <at> sneakemail.com>
Cc: 11928 <at> debbugs.gnu.org
Subject: Re: bug#11928: Spurious bytecomp warning "reference to free variable"
	when variable defined in required library without an initvalue
Date: Fri, 13 Jul 2012 02:21:55 -0400

Michael Hoffman wrote:

> outer.el:5:3:Warning: reference to free variable `inner-a'
> Wrote /net/noble/vol2/home/mmh1/src/experimental/bytecode2/outer.elc
> ====
>
> I expected there to be no warning, as there is no warning for the
> reference of inner-b, which has an initvalue (t).

defvar with no initvalue does not define the variable, it just silences
compilation warnings when the containing file is compiled. But inner.el
is not being compiled.

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