bug#23604: desktop-restore-in-current-display should default to t

[Drew Adams <drew.adams@oracle.com>]

> Leaving it at nil makes no sense to me.  It means that you invoke
> Emacs, which will then display on a different terminal -- could be a
> terminal half a world away.  That could be something that is desired
> in some specialized use cases, but makes no sense at all as the
> default.
> 
> This problem will exist on any platform that supports X displays,
> i.e. on any Posix system.
> 
> > Anyway, the right course of action now (if Emacs 25.1 is released
> > with the default value changed to t) is (after the 25.1 release)
> > to fix bug #20247 and revert the default value to nil.
> 
> No, the right course is to set it to t and leave it at that.

You elided this, just after that paragraph:

  At that point, if there is disagreement about the default value,
  ^^^^^^^^^^^^^
  i.e., if someone really thinks it should be t by design (and not
  just as a workaround), then we can discuss the pros & cons for
  the default behavior.

The proper default value to use, once bug #20274 is fixed, should
be discussed in that context, not in the context of this temporary
workaround (#23604).

Let's have that discussion there and then.
____

As I said before, there are other things that desktop can try to
restore by default that can sometimes not be restored.  And it is
designed to fall back when such a restoration attempt fails.  The
same design applies, a priori, to restoring to a recorded display.
It should be possible to try that and fall back if it is not
possible for some reason (e.g. the display does not exist).

(This is not essentially different from `recentf-exclude' having
a default value of nil, which can lead to problems if the next
session is not in an environment that has access to, for example,
a given host recorded in a remote file or directory entry.)

But we should discuss this later and not here.  This bug is only
about the temporary workaround of setting the value to `t' _to
avoid bug #20274_ rearing its head by default.