Re: Emacs 25.1 RC1: incipient insanity, or can't set debug-on-error.

[Alan Mackenzie]

Hello, Sven.

On Tue, Jul 26, 2016 at 11:08:17PM +0200, Sven Joachim wrote:
> On 2016-07-26 20:34 +0000, Alan Mackenzie wrote:

> > Hello, Emacs.

> > Start RC1 with emacs -Q.

> > M-: debug-on-error returns t.
> > C-h v debug-on-error states that the variable has value nil.  How can
> >   this be?

> > M-: (setq debug-on-error nil) ; in buffer *scratch*, still.
> > M-: debug-on-error returns t.  How can this be?

> See the documentation for debug-on-error:

> ,----
> | debug-on-error is a variable defined in ‘C source code’.
> | Its value is nil
> | 
> | Documentation:
> | [...]
> | When you evaluate an expression interactively, this variable
> | is temporarily non-nil if ‘eval-expression-debug-on-error’ is non-nil.
> `----

> > Why does this variable behave so strangely?  Or am I going mad?  Or,
> > even both?  Should I submit a bug report for this?

> Everything works as designed, AFAICS (by default,
> eval-expression-debug-on-error is t).

Ah.  I see this now.  Thanks for clearing it up!

> Cheers,
>        Sven

-- 
Alan Mackenzie (Nuremberg, Germany).