bug#70593: 30.0.50; Dired: buffers of renamed dirs are broken

[Michael Heerdegen via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> So all we need to do is call expand-file-name on both of them?  Or do
> we need also to call file-truename?

When symlinks are involved it gets really messy.

For example: here is an additional problem I encountered:
`dired-rename-subdir' sometimes doesn't even handle our buffer because
`dired-fun-in-all-buffers', which is built on `dired-buffers-for-dir',
doesn't consider symlinks at all: For `dired-buffers-for-dir' a buffer
that visits some DIR under a different name is simply not visiting DIR.

Other problems are: our buffer could visit a file under a now dead link.
The file renamed could have been moved from behind a link to some
completely unrelated place.  Our buffer could dired a subdirectory of a
renamed directory (this case is currently completely ignored).

I feel a bit lost.  Fixing this would be nice, at least the cases where
this is possible, but it's really complicated and I don't even know the
dired code very well.

Michael.