bug#52349: 29.0.50; vc-git and diff-mode: stage hunks

[Dmitry Gutov]

On 13.02.2022 21:48, Juri Linkov wrote:
> This is fine, so this patch does this:
>
>           (if patch-string
>               (vc-call-backend backend 'checkin files comment rev patch-string)
>             (vc-call-backend backend 'checkin files comment rev))

Looks good, thanks!

Sorry, I haven't noticed your emails today before I wrote my own. See if 
you like the suggestion in there, but this patch is also fine with me. 
Though we might try catching the wrong-number-of-arguments error to 
report a friendlier explanation to the user.

> Also I added the new arg ‘patch-string’ to vc-checkin and vc-start-logentry.
> These are not API calls, so they could use a buffer-local variables instead
> of args, but I'm not sure about this less important technical detail.

Since the new args are optional, should be fine.

> +    (when patch-string
> +      (let ((patch-file (make-temp-file "git-patch")))
> +        (with-temp-file patch-file
> +          (insert patch-string))
> +        (unwind-protect
> +            (apply #'vc-git-command nil 0 patch-file
> +                   (list "apply" "--cached"))
> +          (delete-file patch-file))))

Perhaps we should also check that there are no existing staged changes 
for those files, and if so, abort? This way we won't commit anything 
else by accident.