Merging leaves repo in "still merging" state

After executing a merge as suggested in the docs, a git status suggests that "you are still merging".

Bash:

git init mergable
cd mergable
echo a > a
git add .
git commit -m "initial"
git switch -c mergy
echo b > b
git add b
git commit -m "additional"
git switch master
cd ..
git clone mergable mergable-clone

Python:

import pygit2
r = pygit2.Repository("mergable-clone")
mergy = r.references["refs/remotes/origin/mergy"]
parents = [r.head.target, mergy.target]
r.merge(mergy.target)

r.create_commit(
    "HEAD",
    pygit2.Signature("aaa", "mergy@merge.ch"),
    pygit2.Signature("aaa", "mergy@merge.ch"),
    "merge",
    r.index.write_tree(),
    parents
)

Bash:

cd mergable-clone
git status

Returns:

On branch master
Your branch is ahead of 'origin/master' by 2 commits.
  (use "git push" to publish your local commits)

All conflicts fixed but you are still merging.
  (use "git commit" to conclude merge)

Another git commit silences the message.

Bash と Python のスニペットを使って問題を再現し、その後、r.merge と r.create_commit のエントリポイントと、それらがマージ状態を更新する方法を調べます。git status で動作を確認します。同じコミットフローでリポジトリがまだマージ中であると報告されなくなれば完了です。