bug#72556: 29.1.90; vc-diff does not undo hunk in end of source file

[Eli Zaretskii <eliz@gnu.org>]

> From: Tomas Nordin <tomasn@posteo.net>
> Date: Sat, 10 Aug 2024 12:11:08 +0000
> 
> I have got used to the diff-mode feature of undoing hunks. I have
> noticed that if the diff hunk is an addition in the end of the source
> file, I dont get the expected question if I want to undo the hunk.
> Instead, the hunk is applied again.
> 
> My example is with a git repo, some edits made (and saved to disk) in a
> file, and hitting C-x v = to view the diff. Move to one of the hunks.
> One can now diff-apply-hunk to reverse the hunk. But if that hunk is the
> last thing in the source file, the hunk is applied (again). This is not
> what I expect.
> 
> To reproduce:
> 
> $ mkdir apply
> $ cd apply
> $ echo "first line of code" > example.file
> $ git init
> $ git add .
> $ git commit -m 'init'
> $ echo "last line of code" >> example.file
> $ emacs -Q example.file
> 
> C-x v =
> n
> C-c C-a
> 
> The hunk is applied in the source buffer.

Juri and Dmitry, any comments or suggestions?