Re: Certain numbers of special forms cause changing behaviour on function calls in --batch

[Eli Zaretskii <eliz@gnu.org>]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Cc: me@wilfred.me.uk,  emacs-devel@gnu.org
> Date: Thu, 30 Jun 2016 23:10:58 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Maybe.  But that doesn't help me debug the issue, does it?  Perhaps
> > someone else can, it's not that hard to dig into these things.
> 
> If you are sure it's a bug (I wasn't)

I don't know yet if it is a bug or not.  Debugging can reveal what it
is.

> I can give it a quick try (I'm on vacation).  How would you do
> proceed?

Insert 'message' in strategic places that print values that are
important for the code flow, and see what is different in the batch
session.  In the interactive session, you can step through the code
with Edebug to compare the findings (you will have to manually load
simple.el into a running session).

Just looking at the code, my first suspect would be line-move: it has
a special code for non-interactive sessions, so maybe the issue hides
there somewhere.  Or maybe it's in line-move-1 or the functions it
calls (like vertical-motion).

Thanks.