bug#57807: 29.0.50; Make vc-print-branch-log able to log multiple branches

[Sean Whitton <spwhitton@spwhitton.name>]

Hello,

On Thu 15 Sep 2022 at 08:27PM +03, Juri Linkov wrote:

>>>>> Is this equivalent to `M-& git log origin/scratch/posix-spawn 4b2ca6bfc0`,
>>>>> then enabling vc-git-log-view-mode in the output buffer?
>>>>
>>>> It's not, because vc-git-log-view-mode requires you pass four or five
>>>> options to git-log to get output it can properly display.  That
>>>> knowledge is locked up in vc-git.el right now.
>>>
>>> This part is clear, but I also wanted to know what git command
>>> corresponds to this feature.  Is it just `git log` with two
>>> branch names on the command line?  What additional options
>>> are required?  Maybe `--graph --oneline`?  Also I see that
>>> git documentation mentions `--branches[=<pattern>]`.
>>
>> It's something along these lines:
>>
>> git log -100 --graph --decorate --date=short \
>>     --pretty="tformat:%d%h..: %an %ad %s" --abbrev-commit \
>>     BRANCH1 BRANCH2
>
> This is what I proposed a long ago, maybe it makes sense here.
> After invoking a vc command with a prefix argument it could pop up
> the minibuffer with the command line that you can edit to add or delete
> more arguments for the git command.  So e.g. after 'C-u C-x v b l BRANCH1 RET'
> it will insert in the minibuffer the default command `git log ... BRANCH1`,
> where you can add BRANCH2 and modify any other option.  Then it runs
> this command and displays the output in the vc-git-log-view-mode buffer.

That would be enough for me.  vc-push already works that way.  Shall I
look into preparing a patch?

-- 
Sean Whitton