bug#38044: 27.0.50; There should be an easier way to look at a specific vc commit

[Dmitry Gutov]

On 22.11.2019 1:08, Juri Linkov wrote:
> > The approach LGTM. I'd have used "describe" or "show", but it's not
> > important.
>
> The name vc-print-revision was modeled after vc-print-log,
> vc-print-root-log, vc-print-branch-log that are not the best names
> but at least consistent for their prefix.

Yeah, OK.

> > >       (setq default-directory rootdir)
> >
> > This probably needs a saving (let ((default-directory default-directory))
> > ...) above it.
>
> This is intentional because on testing I discovered that RET
> on the diff part of the buffer can't visit source files
> when default-directory is not root.

I'm saying your code modifies the value of default-directory in the 
original buffer as well. Hence the need for a (let ((...)) before that.

Just like vc-print-root-log does it.

BTW, vc-print-branch-log skips this step, so maybe it also exhibits the 
bug you mentioned. If so, I wonder if we should move the logic changing 
default-directory inside vc-print-log-internal.