Subject: 24.5; Breakpoints don't show in GDB over TRAMP

From: Tim Marston <[email-masked]>
Date: Tue, 24 May 2016 09:35:25 +0100

Hi,

I've noticed that breakpoints don't show up in the source code when
running GDB over TRAMP.  It's quite reproducible.

Steps to reproduce:

1/  run emacs
    $ emacs -q

2/  visit a some remote source code
    C-x C-f /laptop:/home/edam/src/lang/c++/hello-world/hw.cc

3/  run GDB
    M-x gdb RET RET

4/  switch back to source code window
    C-x b RET

5/  add breakpoint
    C-x C-a C-b

What happens:

The breakpoint doesn't show up in the source code buffer.  When you run
the program, the breakpoint still works.  And when the program "breaks
out", you get a current line indicator, showing you where execution is
at.  But no breakpoint.

If you do the same as above, but with a local file (i.e., not via
TRAMP), breakpoints show up as expected.

Another detail, which may be related, is that if I try to set another
breakpoint on the same line, I get this message:

    File /scp:laptop:/home/edam/src/lang/c++/hello-world/"/home/edam/data/dev/lang/c++/hello-world/hw.cc" no longer exists!

Which would seem to indicate that emacs is becoming confused about file
file names over TRAMP.

In GNU Emacs 24.5.1 (x86_64-pc-linux-gnu, GTK+ Version 3.18.9)
 of 2016-04-08 on binet, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.11803000
System Description:	Debian GNU/Linux unstable (sid)

Configured using:
 `configure --build x86_64-linux-gnu --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/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
 --build x86_64-linux-gnu --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/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/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=-Wdate-time
 -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

Important settings:
  value of $LANG: en_GB.utf8
  locale-coding-system: utf-8-unix

Major mode: C++/l

Minor modes in effect:
  shell-dirtrack-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-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 messages:
Tramp: Opening connection for laptop using scp...done
Target doesn't support non-stop mode.  Turning it off.
Command: break hw.cc:5
Use M-x make-directory RET RET to create the directory and its parents

Tramp: Checking `vc-registered' for /scp:laptop:/home/edam/src/lang/c++/hello-world/"/home/edam/data/dev/lang/c++/hello-world/hw.cc"...done
Use M-x make-directory RET RET to create the directory and its parents

Tramp: Checking `vc-registered' for /scp:laptop:/home/edam/data/dev/lang/c++/hello-world/"/home/edam/data/dev/lang/c++/hello-world/hw.cc"...done
Use M-x make-directory RET RET to create the directory and its parents

Load-path shadows:
/usr/share/emacs24/site-lisp/emacs-goodies-el/all hides /usr/share/emacs/24.5/site-lisp/elpa/company-0.8.12/all
/usr/share/emacs24/site-lisp/cmake-data/cmake-mode hides /usr/share/emacs/site-lisp/cmake-mode
/usr/share/emacs/24.5/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs24/site-lisp/psgml/psgml-init hides /usr/share/emacs/site-lisp/psgml/psgml-init
/usr/share/emacs24/site-lisp/psgml/psgml-sysdep hides /usr/share/emacs/site-lisp/psgml/psgml-sysdep
/usr/share/emacs24/site-lisp/psgml/psgml-edit hides /usr/share/emacs/site-lisp/psgml/psgml-edit
/usr/share/emacs24/site-lisp/psgml/psgml-dtd hides /usr/share/emacs/site-lisp/psgml/psgml-dtd
/usr/share/emacs24/site-lisp/psgml/psgml hides /usr/share/emacs/site-lisp/psgml/psgml
/usr/share/emacs24/site-lisp/psgml/psgml-info hides /usr/share/emacs/site-lisp/psgml/psgml-info
/usr/share/emacs24/site-lisp/psgml/psgml-parse hides /usr/share/emacs/site-lisp/psgml/psgml-parse
/usr/share/emacs24/site-lisp/psgml/psgml-ids hides /usr/share/emacs/site-lisp/psgml/psgml-ids
/usr/share/emacs24/site-lisp/psgml/psgml-other hides /usr/share/emacs/site-lisp/psgml/psgml-other
/usr/share/emacs24/site-lisp/psgml/psgml-api hides /usr/share/emacs/site-lisp/psgml/psgml-api
/usr/share/emacs24/site-lisp/psgml/psgml-charent hides /usr/share/emacs/site-lisp/psgml/psgml-charent

Features:
(shadow sort mail-extr emacsbug message rfc822 mml mml-sec mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mail-utils gdb-mi bindat json gud
cc-langs cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs help-mode easymenu tramp-cache tramp-sh tramp
tramp-compat auth-source eieio byte-opt bytecomp byte-compile cl-extra
cl-loaddefs cl-lib cconv eieio-core gnus-util mm-util mail-prsvr
password-cache tramp-loaddefs trampver shell pcomplete comint ansi-color
ring format-spec advice help-fns s ucs-normalize psgml-init
emacs-goodies-el emacs-goodies-custom emacs-goodies-loaddefs easy-mmode
devhelp dash-functional dash time-date tooltip electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd
fontset image regexp-opt fringe tabulated-list newcomment lisp-mode
prog-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 nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
dbusbind gfilenotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs)

Memory information:
((conses 16 257936 12358)
 (symbols 48 24798 0)
 (miscs 40 133 191)
 (strings 32 34368 8660)
 (string-bytes 1 1117099)
 (vectors 16 40099)
 (vector-slots 8 806756 6357)
 (floats 8 639 156)
 (intervals 56 543 1441)
 (buffers 960 22)
 (heap 1024 26132 1165))

--
Tim Marston
ed.am