bug#25194: 25.1; Python debugger breakpoint error

["Andreas Röhler" <andreas.roehler@easy-emacs.de>]

On 13.12.2016 11:10, Live System User wrote:
> Hi,
>
>          When trying to debug a Python program, I get the following
>          error when trying to set a breakpoint:
>
> 0. emaccs -Q &
>
> 1. C-x C-f test.py
>
> 2. From the menubar:  Python->Debugger
>
> Run pdb (like this): python -m pdb test.py
>
> 3. Click on "Next Line" so I can see a source line
>
> 4. Cick on "Set Breakpoint"
>
>     I now get the error:
>     
>        Wrong type argument: stringp, nil
>
>     Turning on `debug-on-error' yields the same results.
>     However, on the *Messages* buffer there is a little more
>     information about the error:
>
>         gud-format-command: Wrong type argument: stringp, nil
>
>     How does one debug this problem further?
>
>     Thanks.
>     
>
>
>
> In GNU Emacs 25.1.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.20.9)
>   of 2016-10-13 built on buildvm-05.phx2.fedoraproject.org
> Windowing system distributor 'Fedora Project', version 11.0.11803000
> Configured using:
>   'configure --build=x86_64-redhat-linux-gnu
>   --host=x86_64-redhat-linux-gnu --program-prefix=
>   --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr
>   --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
>   --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
>   --libexecdir=/usr/libexec --localstatedir=/var
>   --sharedstatedir=/var/lib --mandir=/usr/share/man
>   --infodir=/usr/share/info --with-dbus --with-gif --with-jpeg --with-png
>   --with-rsvg --with-tiff --with-xft --with-xpm --with-x-toolkit=gtk3
>   --with-gpm=no --with-xwidgets build_alias=x86_64-redhat-linux-gnu
>   host_alias=x86_64-redhat-linux-gnu 'CFLAGS=-DMAIL_USE_LOCKF -O2 -g
>   -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
>   -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4
>   -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
>   -m64 -mtune=generic' LDFLAGS=-Wl,-z,relro
>   PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig'
>
> Configured features:
> XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GCONF GSETTINGS NOTIFY
> ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
> TOOLKIT_SCROLL_BARS GTK3 X11 XWIDGETS
>
> Important settings:
>    value of $LANG: en_US.UTF-8
>    value of $XMODIFIERS: @im=ibus
>    locale-coding-system: utf-8-unix
>
> Major mode: Summary
>
> Minor modes in effect:
>    tooltip-mode: t
>    global-eldoc-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
>    buffer-read-only: t
>    line-number-mode: t
>    transient-mark-mode: t
>
> Recent messages:
> Scoring...done
> Sorting threads...done
> Generating summary...done
>
> Load-path shadows:
> None found.
>
> Features:
> (shadow emacsbug sendmail sort gnus-cite smiley ansi-color mm-archive
> mail-extr gnus-async gnus-bcklg qp gnus-ml disp-table cursor-sensor
> nndraft nnmh nndoc utf-7 rfc2104 nnfolder network-stream nsm starttls
> gnus-agent gnus-srvr gnus-score score-mode nnvirtual gnus-msg gnus-art
> mm-uu mml2015 mm-view mml-smime smime dig mailcap nntp gnus-cache
> epa-file epa derived auth-source cl-seq eieio byte-opt bytecomp
> byte-compile cl-extra cconv eieio-core cl-macs gv sieve sieve-mode
> sieve-manage nnir gnus-sum gnus-group gnus-undo gnus-start gnus-cloud
> nnimap nnmail mail-source tls gnutls utf7 netrc parse-time gnus-spec
> gnus-int gnus-range message dired format-spec rfc822 mml mml-sec
> password-cache epg epg-config mm-decode mm-bodies mm-encode mail-parse
> rfc2231 rfc2047 rfc2045 ietf-drums mailabbrev gmm-utils mailheader
> gnus-win gnus gnus-ems wid-edit nnoo nnheader gnus-util mm-util help-fns
> help-mode easymenu cl-loaddefs pcase cl-lib mail-prsvr mail-utils
> time-date mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
> lisp-float-type mwheel x-win term/common-win x-dnd tool-bar dnd fontset
> image regexp-opt fringe tabulated-list newcomment elisp-mode lisp-mode
> prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
> mouse jit-lock font-lock syntax facemenu font-core frame 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 charscript case-table epa-hook
> jka-cmpr-hook help simple abbrev minibuffer cl-preloaded 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 dbusbind inotify dynamic-setting
> system-font-setting font-render-setting xwidget-internal move-toolbar
> gtk x-toolkit x multi-tty make-network-process emacs)
>
> Memory information:
> ((conses 16 3415290 60696)
>   (symbols 48 122996 45)
>   (miscs 40 154 602)
>   (strings 32 91188 15607)
>   (string-bytes 1 3394373)
>   (vectors 16 23139)
>   (vector-slots 8 4832715 8719)
>   (floats 8 367 785)
>   (intervals 56 8533 172)
>   (buffers 976 43)
>   (heap 1024 153578 105539))
>
>
>

Here it works calling just

pdb test.py

not "python -m"before