Subject: bug#52196: 28.0.60; gdb-mi error message: "wrong type argument: stringp"

From: [email-masked]
Date: Tue, 30 Nov 2021 10:08:00 +0000

I've attached a small C++ program that can be used to reproduce the issue. I compiled it like so

g++ -g3 main.cc -o test-program

Steps to reproduce:
- emacs -Q
- evaluate the forms:
(require 'gdb-mi)
(setq gdb-many-windows t)

- M-x gdb with argument "gdb -i=mi /path/to/test-program"
- Do "run" in the gdb command prompt
- M-x gdb-io-interrupt

Result: error message in minibuffer "Wrong type argument: stringp, nil" (although the command executes normally).

Furthermore, in this state any of the following will also cause the same message to flash:
- doing M-x gud-break in the source buffer
- toggling a breakpoint in the breakpoint buffer
- probably others

Although again none of the commands fail to execute properly.

Root cause:

In the function gdb-frame-handler the form:

(setq gdb-selected-file (file-local-name (gdb-mi--field frame 'fullname)))

causes the error message if gdb-mi--field returns nil. I don't know if this is an expected return value for that function or not. In any case, file-local-name signals the error in case of nil input. The file-local-name wrapping was introduced semi-recently with commit 019c70e731d0243ad3ea2d4ebb02dd4a343e868f.

Thanks.

----------------------------------------

In GNU Emacs 28.0.60 (build 8, x86_64-pc-linux-gnu, GTK+ Version 3.22.30, cairo version 1.15.12)
 of 2021-11-30 built on san
Repository revision: 30553d889d733613e8e5fd22358980baa7ee148e
Repository branch: emacs-28
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: CentOS Linux 8

Configured using:
 'configure --prefix=/home/snorgaard/emacs-master --with-cairo
 --with-dumping=pdumper --with-mailutils --with-json --with-x
 --with-xwidgets --with-native-compilation
 --enable-link-time-optimization 'CFLAGS=-g3 -O3 -mtune=native
 -march=native -fomit-frame-pointer''

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LCMS2 LIBSELINUX LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG
RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE XIM XPM
XWIDGETS GTK3 ZLIB

Important settings:
  value of $LANG: en_DK.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: C++//l

Minor modes in effect:
  gdb-many-windows: 1
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-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
  indent-tabs-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg rfc6068 epg-config gnus-util rmail
rmail-loaddefs auth-source eieio eieio-core eieio-loaddefs
password-cache json map text-property-search mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils time-date
cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine
cc-vars cc-defs comp comp-cstr warnings subr-x rx cl-macs cl-extra
help-mode seq byte-opt gv bytecomp byte-compile cconv gdb-mi cl-seq
cl-loaddefs cl-lib gud easy-mmode comint ansi-color ring iso-transl
tooltip eldoc paren electric uniquify ediff-hook vc-hooks
lisp-float-type elisp-mode mwheel term/x-win x-win term/common-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list replace
newcomment text-mode lisp-mode prog-mode register page tab-bar menu-bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer cl-generic
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help simple abbrev obarray
cl-preloaded nadvice button loaddefs faces cus-face macroexp files
window text-properties overlay sha1 md5 base64 format env code-pages
mule custom widget hashtable-print-readable backquote threads
xwidget-internal dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting cairo move-toolbar gtk x-toolkit
x multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 134661 11459)
 (symbols 48 10813 0)
 (strings 32 31925 1896)
 (string-bytes 1 1182054)
 (vectors 16 20650)
 (vector-slots 8 362625 14622)
 (floats 8 46 30)
 (intervals 56 365 3)
 (buffers 992 19))