Hi,

I wanted to discuss the best way to solve this bug before going any
further in the development:

> (gdb) py print gdb.frame_stop_reason_string(2)
> /home/kevin/travail/git/gdb/gdb/frame.c:2372: internal-error: Invalid frame stop reason
> A problem internal to GDB has been detected,further debugging may prove unreliable.


I prepared the attached patch, which requires to change
'internal_error' to a simple 'error' (I assume that it can't break
anything because it ends up calling `exit()', but I didn't check yet),

but "Frame.unwind_stop_reason ()" easily returns 'invalid frame stop
reason', for instance

> (gdb) start
> ...
> (gdb) pp gdb.newest_frame().unwind_stop_reason()
> 0

so I'm not convinced that it's the best solution.

Would it be better to return (in frame_stop_reason_string) a reason
for each value of "enum unwind_stop_reason reason", but breaking the
original intend of the `internal_error' call?

thanks for your comments,

Kevin