Subject: 29.1.90; vc-diff does not undo hunk in end of source file
From: Tomas Nordin <[email-masked]>
To: [email-masked]
Date: Sat, 10 Aug 2024 12:11:08 +0000
List-Id: <debbugs-submit.debbugs.gnu.org>

Hello Emacs

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.

In GNU Emacs 29.1.90 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.38, cairo version 1.16.0) of 2023-11-18 built on fliptop2
Repository revision: d9e43f2197fa1d5ade1d483b15cc50c6d705b969
Repository branch: emacs-29
Windowing system distributor 'The X.Org Foundation', version 11.0.12101007
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