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

[Dmitry Gutov]

On 21.11.2019 16:59, Eli Zaretskii wrote:
> I'd prefer this to be a variant of vc-diff, and bound to "C-x v =".
> The "C-u C-x v =" form is already taken, and tweaking it to accept a
> single revision would not be easy.  So how about "C-u C-u C-x v ="?

Okay, I see what you mean now: you're basically suggesting to tackle the 
new behavior (the one everybody wants apparently) on top the 'diff' 
backend action. Which can kind of work, but I don't see why we would 
make that choice.

Adding a new backend command is relatively cheap, and we won't force the 
backend implementation to try to reconcile incompatible arguments (e.g. 
REV1 that is not a parent of REV2 and SHOW-METADATA=t).

I also think the current patch proposed by Juri is cleaner than the one 
that is required to implement your idea.

Finally, "C-u C-u C-x v =" doesn't look semantic enough for me (revision 
!= diff in my mind, at least not entirely). I think it would be nicer to 
have a new command, but opinions welcome on this.