bug#63949: 30.0.50; `vc-print-log´ does not erase buffer when called from *vc-change-log* buffer, at least for CVS logs

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

On 2023-06-10  19:23, Eli Zaretskii wrote:

> If the backend is a VCS that records changes per-file, what you want 
> will happen automatically, since "C-x v l" and other operations must 
> in general refer to a file with those VCSes.  For backends that
> record changes per-repository, why does it make sense that typing
> "C-x v l" from a buffer that already shows a log should produce the
> same log again?

To get it updated, for example because I perform some operation outside
of Emacs.  One of these habits ...

> If you can suggest changes to make the treatment of vc-parent-buffer 
> more consistent, that would be good, I think.

Here is another minor ugliness I forgot to mention so far which also
should be defined and fixed, then: Whenever the `vc-parent-buffer' goes
"out of sync" (as far as I am concerned) in some VC working buffer, its
mode line shows, e.g.

   *vc-change-log*   Top   1   (Git-Log-View from *vc-change-log*)

or

   *vc-diff [...] (Diff ws from *vc-diff*)

since mode line variable `vc-parent-buffer-name' goes likewise out of sync.

> I'd also like to hear Dmitry's views on these issues.  He was until 
> now silent in this discussion, AFAICT.

Agreed.