Subject: Re: bug#67196: M-: uses a wrong value of debug-on-error when it is nil.

From: Eli Zaretskii <[email-masked]>
Date: Sat, 25 Nov 2023 17:50:09 +0200

> Date: Sat, 25 Nov 2023 14:14:59 +0000
> Cc: [email-masked], [email-masked], [email-masked]
> From: Alan Mackenzie <[email-masked]>
> 
> > No, I meant with the current code debug-on-error is set to t whenever
> > eval-expression-debug-on-error is non-nil, ....
> 
> Yes.
> 
> > .... and your change sets it to the same value as
> > eval-expression-debug-on-error instead.
> 
> That is not what is meant to happen.

We are miscommunicating.

> Instead, the new internal variable
> debug-from--eval-expression gets set to e-e-debug-on-error.

Exactly.  And that value can be non-nil, but also not t.  That is the
change I see, and your doc string suggests that it is intentional.
Thus, we have a behavior change wrt to the value that the body of
eval-expression will see.  And non-nil, non-t values have special
meaning there.