bug#10025: 24.0.91; Lisp debugger not working right

[Uday S Reddy <u.s.reddy@cs.bham.ac.uk>]

The Lisp debugger is still not working right in the Emacs 24 pre-release.
(The old bug reports were #6209 and #9462.)

(defun a ()
  (b)
  (c))

(defun b ()
  (message "b entered"))

(defun c ()
  (message "c entered"))

Place a debug-on-entry on `b' and `c'

When `b' is entered, the backtrace buffer shows:
-----
Debugger entered--entering a function:
  b()
* a()
  eval((a) nil)
  eval-expression((a) nil)
  call-interactively(eval-expression nil nil)
-----
Note that there is a spurious breakpoint on `a', and no breakpoint on `b'.


Typing c at this stage goes to `c'.  The return point of `b' is skipped.
----
Debugger entered--entering a function:
  c()
* a()
  eval((a) nil)
  eval-expression((a) nil)
  call-interactively(eval-expression nil nil)
---

Another c shows the return point of `a', skipping the return point of `c'.
---
Debugger entered--returning value: "c entered"
  a()
  eval((a) nil)
  eval-expression((a) nil)
  call-interactively(eval-expression nil nil)
---

Placing new brakpoints on the frames of `b' or `c' in the debugger through
the "b" command, doesn't help.  They get ignored!

Cheers,
Uday



If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
d:/gnu/emacs-24.0.91/etc/DEBUG.


In GNU Emacs 24.0.91.1 (i386-mingw-nt5.1.2600)
 of 2011-10-31 on MARVIN
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.6) --no-opt --cflags -I"D:/devel/emacs/libs/libXpm-3.5.8/include" -I"D:/devel/emacs/libs/libXpm-3.5.8/src" -I"D:/devel/emacs/libs/libpng-dev_1.4.3-1/include" -I"D:/devel/emacs/libs/zlib-dev_1.2.5-2/include" -I"D:/devel/emacs/libs/giflib-4.1.4-1/include" -I"D:/devel/emacs/libs/jpeg-6b-4/include" -I"D:/devel/emacs/libs/tiff-3.8.2-1/include" -I"D:/devel/emacs/libs/gnutls-2.10.1/include" --ldflags -L"D:/devel/emacs/libs/gnutls-2.10.1/lib"'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ENU
  value of $XMODIFIERS: nil
  locale-coding-system: cp1252
  default enable-multibyte-characters: t

Major mode: Mail

Minor modes in effect:
  savehist-mode: t
  show-paren-mode: t
  which-function-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Recent input:
<return> C-x , <down-mouse-1> <mouse-movement> <mouse-1> 
<down-mouse-1> <mouse-1> <help-echo> <switch-frame> 
<down-mouse-1> <mouse-movement> <mouse-1> <return> 
<return> ( d e f u n SPC a ( ) <backspace> <backspace> 
SPC ( ) <return> TAB ( b ) <return> TAB ( c ) ) <return> 
<return> ( d e f u n SPC b S-SPC ( ) <return> TAB ( 
m e s s a g e SPC " b " <backspace> SPC e n t e r e 
d " ) ) <return> <return> ( d e f u n SPC c SPC ( ) 
<return> TAB ( m e s a g e <backspace> <backspace> 
<backspace> s a g e SPC " c SPC e n t e r e d ) ) <backspace> 
) <backspace> <backspace> " ) ) <return> C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-n C-o TAB ( i n t e r a c 
t i v e ) C-p C-a C-SPC C-x . M-x e v a l - r e g SPC 
<return> C-x C-g M-x d e b u g - o n - e n SPC <return> 
a <return> M-x a C-g C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-k C-k <escape> C-x <escape> : ( a ) <return> 
M-x d e b u g - o n - e n SPC <return> a <return> <escape> 
: ( a ) <return> d c d c d c <escape> : ( a ) <return> 
<switch-frame> M-x r e p o r t - e m a c s - b u SPC 
<return>

Recent messages:
Proceeding, will debug on next eval or call.
Entering debugger...
Continuing.
c entered
Entering debugger...
Proceeding, will debug on next eval or call.
Entering debugger...
Continuing.
"c entered"
Entering debugger...

Load-path shadows:
d:/Home/udr/share/emacs/sml-mode hides d:/gnu/emacs-24.0.91/../site-lisp/sml-mode
d:/Home/udr/share/emacs/savehist-20+ hides d:/gnu/emacs-24.0.91/../site-lisp/savehist-20+
d:/gnu/emacs-24.0.91/../site-lisp/longlines hides d:/gnu/emacs-24.0.91/lisp/longlines
d:/gnu/vm/trunk/lisp/cus-load hides d:/gnu/emacs-24.0.91/lisp/cus-load

Features:
(smtpmail vm-crypto network-stream starttls tls vm-imap message format-spec
mml mml-sec mm-decode mm-bodies mm-encode gmm-utils mailheader flyspell
ispell newcomment shadow emacsbug multi-isearch cl-specs edebug help-mode
view debug mailalias vm-reply bbdb-hooks mail-parse rfc2231 w3m-form w3m
browse-url doc-view jka-compr dired-x mydired dired image-mode w3m-hist
w3m-fb bookmark-w3m w3m-ems wid-edit w3m-ccl ccl w3m-favicon w3m-image
w3m-proc w3m-util vm-w3m tapestry vm-sort vm-thread easymenu u-vm-color
my-vm vc-bzr etags ps-print ps-def lpr vm-save vm-ps-print vm-rfaddons
vm-menu vm-window vm-toolbar vm-folder vm-mime vm-undo vm-virtual
vm-summary-faces vm-mouse vm-page vm-minibuf vm-message vm-misc vm-macro
bbdb-vm vm-summary vm-motion vm-autoload bbdb-snarf mail-extr rfc822
bbdb-com mailabbrev vm warnings server w3m-load bbdb-autoloads bbdb timezone
vm-autoloads vm-version vm-vars autopair easy-mmode cl myautopair savehist
tex-site auto-loads telnet movement natural-space NatSpeak sendmail rfc2047
rfc2045 ietf-drums mail-utils auth-source eieio byte-opt bytecomp
byte-compile cconv macroexp assoc gnus-util mm-util mail-prsvr
password-cache epa-file epa epg epg-config ange-ftp comint regexp-opt ring
paren echistory chistory ehelp electric derived which-func imenu advice
help-fns advice-preload edmacro kmacro time-date tooltip ediff-hook vc-hooks
lisp-float-type mwheel dos-w32 disp-table ls-lisp w32-win w32-vars tool-bar
dnd fontset image fringe lisp-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer button faces cus-face files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote make-network-process multi-tty emacs)