bug#64163: 29.0.92; Syntactic errors in early init when --debug-init is on

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Sebastian Miele <iota@whxvd.name>,  64163@debbugs.gnu.org
> Date: Tue, 20 Jun 2023 10:24:31 -0400
> 
> > First, the --init-directory=$DIR part is not relevant to the issue;
> > the same happens if you place such init files in your "normal" home
> > directory.
> 
> [ IIUC he used it so we can reproduce his recipe without having to
>   mess with our config.  Thanks Sebastien for that effort :-)  ]

I usually start a new shell and set HOME there to point to some
scratch directory.

The problem with using --init-directory= in this particular case is
that this is a new feature in Emacs 29, so I was initially afraid we
have some subtle bug in it.

> I think `debug-ignored-errors` should keep its default value when
> `--debug-init` is not used.
> 
> IOW `--debug-init` should be the one that sets `debug-ignored-errors` to
> nil

So you are saying it should be condition on init-file-debug being
non-nil?

Incidentally, do you happen to know the difference between that
variable having the value t and 'startup'?  I don't see anywhere that
we assign any different non-nil value to it.

> (only while loading the init files, tho).

OK.

> > Stefan, WDYT?  Should we perhaps condition this binding by more
> > conditions, like only do this in interactive invocations or something?
> 
> That would also be worth a try, yes.

OK, thanks.