diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index aae14090bd..f38827529f 100755
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -119,7 +119,7 @@ get_author_ident_from_commit () {
 	}
 	'
 	encoding=$(git config i18n.commitencoding || echo UTF-8)
-	git show -s --pretty=raw --encoding="$encoding" "$1" |
+	git show -s --pretty=raw --encoding="$encoding" "$1" -- |
 	LANG=C LC_ALL=C sed -ne "$pick_author_script"
 }
 
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index e33ea4e9f4..e5ed74545b 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -340,4 +340,26 @@ test_expect_success 'rebase a commit violating pre-commit' '
 
 '
 
+test_expect_success 'rebase with a file named HEAD in worktree' '
+
+	rm -fr .git/hooks &&
+	git reset --hard &&
+	git checkout -b branch3 A &&
+
+	(
+		GIT_AUTHOR_NAME="Squashed Away" &&
+		export GIT_AUTHOR_NAME &&
+		>HEAD &&
+		git add HEAD &&
+		git commit -m "Add head" &&
+		>BODY &&
+		git add BODY &&
+		git commit -m "Add body"
+	) &&
+
+	FAKE_LINES="1 squash 2" git rebase -i to-be-rebased &&
+	test "$(git show -s --pretty=format:%an)" = "Squashed Away"
+
+'
+
 test_done