weird defadvice bug with byte-compilation

[Drew Adams]

This is a weird one. I've pared it down to the bare bones, I think -
if I comment out any part of this, the bug doesn't occur. This
obviously comes from a larger context - when it is pared down, the
code doesn't make much sense, of course.

If the stuff is in the same file, or the order is different, no bug
(error). It must be like this: two files, one of which is compiled and
required by the other. And the requiring file must have "compile" in
its defadvice.

Two files:

File 1: foo.el
--------------

(defvar mymap nil "")

(let ((map (make-sparse-keymap "II")))
  (setq mymap (make-sparse-keymap))
  (define-key menu-bar-search-menu [ise]  '("" . ise))
  (put 'ise 'menu-enable '(and my-mode))
  (push (cons 'my-mode mymap) minor-mode-map-alist))

(defadvice next-history-element (after ffff activate) "" my-mode)

(provide 'foo)

File 2: bar.el
--------------

(defconst special-display-regexps '("[ ]?[*][^*]+[*]"))

(defvar drews-lisp-dir "C:\\drews-lisp-20" "")
(setq load-path (append (list drews-lisp-dir) load-path))


(defadvice occur-mode-goto-occurrence
  (around jjjjjj activate compile)
  ""
  ad-do-it)

(require 'foo)

Instructions:
-------------

1. emacs -q

2. Byte-compile foo.el (it doesn't matter if it's compiled on Emacs 20
   or 22). `C-x C-c'.

3. emacs -q    (Emacs 22)

4. Visit bar.el - don't load it.

5. Select everything in bar.el except the (require 'foo), and do
`eval-region'.

6. Put the cursor just after the (require 'foo) and do `C-x C-e'. (Don't
select it and do eval-region - that doesn't produce the bug!)

You will get this error backtrace:

Debugger entered--Lisp error: (void-variable my-mode)
  (and my-mode)
  x-create-frame(((visibility) (height . 14) (width . 80) (unsplittable .
t)))
  x-create-frame-with-faces(((height . 14) (width . 80) (unsplittable . t)))
  make-frame(((height . 14) (width . 80) (unsplittable . t)))
  special-display-popup-frame(#<buffer *Compile-Log*>)
  display-buffer(#<buffer *Compile-Log*>)
  display-warning(bytecomp "reference to free variable `my-mode'" :warning
"*Compile-Log*")
  byte-compile-log-warning("reference to free variable `my-mode'" t
:warning)
  byte-compile-warn("reference to free variable `%s'" my-mode)
  byte-compile-variable-ref(byte-varref my-mode)
  byte-compile-form(my-mode t)
  byte-compile-body(((setq ad-return-value (ad-Orig-next-history-element n))
my-mode ad-return-value) nil)
  byte-compile-let((let (ad-return-value) (setq ad-return-value
(ad-Orig-next-history-element n)) my-mode ad-return-value))
  byte-compile-form((let (ad-return-value) (setq ad-return-value
(ad-Orig-next-history-element n)) my-mode ad-return-value) nil)
  byte-compile-top-level((progn (let (ad-return-value) (setq ad-return-value
...) my-mode ad-return-value)) nil lambda)
  byte-compile-lambda((lambda (n) "$ad-doc: next-history-element$"
(interactive "p") (let (ad-return-value) (setq ad-return-value ...) my-mode
ad-return-value)))
  #[nil "???                    \n
\f
??


7. `C-x C-c'

You will get a pop-up message with Yes/No buttons that says this:

Emacs Abort Dialog

"A fatal error has occurred! Would you like to attach a debugger? Select YES
to debu, NO to abort Emacs"

If you select Yes, you get a Window program exception and an invitation to
send the details to Microsoft. The error report contents are these:

Exception Information
Code 0x80000003 Flags: 0x00000000
Record: 0x0000000000000000 (didn't count 'em) Address: 0x0000000077f75a58

System Information
Windows NT 5.1 Build: 2600
CPU Vendor Code etc. blah blah blah

Module 1
emacs.exe
blah blah

Module 2
ntdll.dll
blah blah

Module 3
kernel32.dll
blah blah

Module 4
msvcrt.dll
blah blah

etc. etc.

------------------------------------
In GNU Emacs 22.0.50.1 (i386-mingw-nt5.1.2600)
 of 2005-06-26 on NONIQPC
X server distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc
(3.3) --cflags -I../../jpeg-6b-3/include -I../../libpng-1.2.8/include -I../.
./tiff-3.6.1-2/include -I../../xpm-nox-4.2.0/include -I../../zlib-1.2.2/incl
ude'