Re: master 40e1174: Print a backtrace on unhandled errors in batch mode (Bug#44942).

[Philipp Stephani <p.stephani2@gmail.com>]

Am Mo., 7. Dez. 2020 um 16:49 Uhr schrieb Eli Zaretskii <eliz@gnu.org>:
>
> > From: Lars Ingebrigtsen <larsi@gnus.org>
> > Date: Mon, 07 Dec 2020 12:30:47 +0100
> > Cc: Philipp Stephani <p.stephani2@gmail.com>, emacs-devel@gnu.org
> >
> > I think it would be good if there was a command line switch for this
> > (for instance, -backtrace).
> >
> > Outputting a backtrace in -batch mode is good, but I think having it on
> > by default will lead to too many regressions.
>
> IMO, we should first decide whether this new behavior should be the
> default, and only after that whether it should be controlled by a
> command-line switch.  E.g., if we believe that most users will want
> the backtrace, i.e. the default behavior will be to produce a
> backtrace, then a command-line switch is hardly necessary or
> justified.

While I certainly can't speak for most/all users, I find it hard to
imagine why anybody would not want the backtrace. The backtrace is
only printed if there's no error handler. In case of a batch job (i.e.
a scripted/noninteractive invocation) that's almost always a bug or
runtime issue (expected file missing, etc.), and the backtrace is
often the only way to debug the issue.
I also don't believe that printing the backtrace by default will break
users: parsing error messages is brittle, and we can't realistically
guarantee stability in such an area.