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diff --git a/t/t6404-recursive-merge.sh b/t/t6404-recursive-merge.sh
new file mode 100755
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+++ b/t/t6404-recursive-merge.sh
@@ -0,0 +1,147 @@
+#!/bin/sh
+
+test_description='Test merge without common ancestors'
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./test-lib.sh
+
+# This scenario is based on a real-world repository of Shawn Pearce.
+
+# 1 - A - D - F
+#   \   X   /
+#     B   X
+#       X   \
+# 2 - C - E - G
+
+GIT_COMMITTER_DATE="2006-12-12 23:28:00 +0100"
+export GIT_COMMITTER_DATE
+
+test_expect_success 'setup tests' '
+	GIT_TEST_COMMIT_GRAPH=0 &&
+	export GIT_TEST_COMMIT_GRAPH &&
+	echo 1 >a1 &&
+	git add a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:00" git commit -m 1 a1 &&
+
+	git checkout -b A main &&
+	echo A >a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:01" git commit -m A a1 &&
+
+	git checkout -b B main &&
+	echo B >a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:02" git commit -m B a1 &&
+
+	git checkout -b D A &&
+	git rev-parse B >.git/MERGE_HEAD &&
+	echo D >a1 &&
+	git update-index a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:03" git commit -m D &&
+
+	git symbolic-ref HEAD refs/heads/other &&
+	echo 2 >a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:04" git commit -m 2 a1 &&
+
+	git checkout -b C &&
+	echo C >a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:05" git commit -m C a1 &&
+
+	git checkout -b E C &&
+	git rev-parse B >.git/MERGE_HEAD &&
+	echo E >a1 &&
+	git update-index a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:06" git commit -m E &&
+
+	git checkout -b G E &&
+	git rev-parse A >.git/MERGE_HEAD &&
+	echo G >a1 &&
+	git update-index a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:07" git commit -m G &&
+
+	git checkout -b F D &&
+	git rev-parse C >.git/MERGE_HEAD &&
+	echo F >a1 &&
+	git update-index a1 &&
+	GIT_AUTHOR_DATE="2006-12-12 23:00:08" git commit -m F &&
+
+	test_oid_cache <<-EOF
+	idxstage1 sha1:ec3fe2a791706733f2d8fa7ad45d9a9672031f5e
+	idxstage1 sha256:b3c8488929903aaebdeb22270cb6d36e5b8724b01ae0d4da24632f158c99676f
+	EOF
+'
+
+test_expect_success 'combined merge conflicts' '
+	test_must_fail git merge -m final G
+'
+
+test_expect_success 'result contains a conflict' '
+	cat >expect <<-\EOF &&
+	<<<<<<< HEAD
+	F
+	=======
+	G
+	>>>>>>> G
+	EOF
+
+	test_cmp expect a1
+'
+
+test_expect_success 'virtual trees were processed' '
+	# TODO: fragile test, relies on ambigious merge-base resolution
+	git ls-files --stage >out &&
+
+	cat >expect <<-EOF &&
+	100644 $(test_oid idxstage1) 1	a1
+	100644 $(git rev-parse F:a1) 2	a1
+	100644 $(git rev-parse G:a1) 3	a1
+	EOF
+
+	test_cmp expect out
+'
+
+test_expect_success 'refuse to merge binary files' '
+	git reset --hard &&
+	printf "\0" >binary-file &&
+	git add binary-file &&
+	git commit -m binary &&
+	git checkout G &&
+	printf "\0\0" >binary-file &&
+	git add binary-file &&
+	git commit -m binary2 &&
+	test_must_fail git merge F >merge.out 2>merge.err &&
+	grep "Cannot merge binary files: binary-file (HEAD vs. F)" merge.err
+'
+
+test_expect_success 'mark rename/delete as unmerged' '
+
+	git reset --hard &&
+	git checkout -b delete &&
+	git rm a1 &&
+	test_tick &&
+	git commit -m delete &&
+	git checkout -b rename HEAD^ &&
+	git mv a1 a2 &&
+	test_tick &&
+	git commit -m rename &&
+	test_must_fail git merge delete &&
+	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
+	then
+		test 2 = $(git ls-files --unmerged | wc -l)
+	else
+		test 1 = $(git ls-files --unmerged | wc -l)
+	fi &&
+	git rev-parse --verify :2:a2 &&
+	test_must_fail git rev-parse --verify :3:a2 &&
+	git checkout -f delete &&
+	test_must_fail git merge rename &&
+	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
+	then
+		test 2 = $(git ls-files --unmerged | wc -l)
+	else
+		test 1 = $(git ls-files --unmerged | wc -l)
+	fi &&
+	test_must_fail git rev-parse --verify :2:a2 &&
+	git rev-parse --verify :3:a2
+'
+
+test_done