bug#51883: 29.0.50; Command to get accidentally deleted frames back

[Juri Linkov <juri@linkov.net>]

>> >> So all concerns raised by Eli are addressed now
>> >> that make possible to enable it by default
>> >> as was discussed on emacs-devel:
>> >
>> > Once again, please do NOT enable this by default, I didn't agree to
>> > that.  This feature should remain disabled by default for some time,
>> > until we have enough information to discuss whether it should be
>> > turned on by default.  As discussed and agreed during its development.
>>
>> But after the recent discussion it was agreed to enable it by default
>> after fixing raised concerns.  Everything is fixed now.
>> Should we restart the same discussion again?
>
> I see no need to restart that discussion, since we won't hear anything
> new in it.  We made a decision back then, and there's no burning
> reason to change that decision, except that some people would like to
> have that feature turned on -- they can tun it on in their
> customizations.
>
> We discuss stuff and make decisions, and we should stick to our
> decisions unless they turn out to be grave mistakes, which this one
> isn't.

Unfortunately, this is a grave mistake, so it needs more discussion
on emacs-devel.

>> >>  @item C-x 5 u
>> >>  @kindex C-x 5 u
>> >>  @findex undelete-frame
>> >> -@findex undelete-frame-mode
>> >> -When @code{undelete-frame-mode} is enabled, undelete one of the 16
>> >> -most recently deleted frames.  Without a prefix argument, undelete the
>> >> -most recently deleted frame.  With a numerical prefix argument between
>> >> -1 and 16, where 1 is the most recently deleted frame, undelete the
>> >> -corresponding deleted frame.
>> >> +@findex undelete-frame-max
>> >> +Undelete one of the recently deleted frames.  The user option
>> >
>> > "One of the recently deleted frames" sounds like Emacs arbitrarily
>> > decides which one.  Which is not  what you wanted to say, surely.
>>
>> This was copied from old text: "undelete one of the 16 most recently deleted frames".
>
> Does that mean we must blindly copy it, even if it is confusing?

I will fix this, once the patch is accepted.

>> >> +(defcustom undelete-frame-max 1
>> >> +  "Maximum number of deleted frames before oldest are thrown away."
>> >
>> > This doesn't say how to disable the feature.
>>
>> This feature can be disabled by customizing it to 0.
>
> I know.  But the doc string keeps silent on that.

Will fix this as well.

>> >>      (bindings--define-key menu [undelete-last-deleted-frame]
>> >>        '(menu-item "Undelete Frame" undelete-frame
>> >> -                  :enable (and undelete-frame-mode
>> >> -                                (car undelete-frame--deleted-frames))
>> >> +                  :visible (car undelete-frame--deleted-frames)
>> >
>> > I think Gregory didn't like the disappearing item, and preferred it to
>> > be visible at all times, even if disabled.
>>
>> The invisible item makes the already overly long menu shorter,
>> especially for users who don't use frames.
>
> So you basically say we should disregard Gregory's opinion and prefer
> yours?

This definitely needs more discussion, so I'll post the problem's description
on emacs-devel.