bug#27968: 26.0.50; dired-revert: Saved positions might change if a dired header changes

[Tino Calancha]

On Sat, 5 Aug 2017, Eli Zaretskii wrote:

> > From: Tino Calancha <tino.calancha@gmail.com>
> > Date: Sat, 05 Aug 2017 22:01:34 +0900
> > Cc: stephen berman <stephen.berman@gmx.net>
> >
> > Dired headers also changes; if you add/deleted some files,
> > the used space shown changes: that will mess up the saved
> > buffer positions if the length of the header is different.
> >
> > This problem causes dired-test-bug27243-01 to fail in hydra.
> >
> > One possible solution is the patch below.  It saves line numbers
> > instead of positions.  Line numbers won't change if a dired header
> > changes its length.
>
> Won't using markers be a better solution?
Yes, but `dired-revert' erases the buffer when calls
`dired-readin', so that the markers will 'gone baby gone': neither
the very same Casey Affleck could recover those markers.