bug#25194: 25.1; Python debugger breakpoint error

[Andreas Röhler]

On 13.12.2016 13:25, Live System User wrote:
> Andreas Röhler <andreas.roehler@easy-emacs.de> writes:
>
> > 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.
> > >      
> [...]
> > Here it works calling just
> >
> > pdb test.py
> >
> > not "python -m"before
>    Normally, `pdb' is just a shell script that calls/execs
>    the Python debugger containing:
>
>      exec $python -m pdb $1 $2 $3 $4 $5 $6 $7 $8 $9
>
>
>   
As described
From the menubar: Python->Debugger

That means being in an Emacs-buffer connected to Python-process in a 
special way.
The command to insert must match the environment, but didn't. That's why 
"gud-format-command:" raised the error.


IIUC `debug-on-error' adresses Emacs-lisp errors, not the Python-side.

>