1 files changed, 159 insertions, 0 deletions
diff --git a/t/t7607-merge-overwrite.sh b/t/t7607-merge-overwrite.sh
new file mode 100755
index 0000000000..4d5ce4e682
--- /dev/null
+++ b/t/t7607-merge-overwrite.sh
@@ -0,0 +1,159 @@
+#!/bin/sh
+
+test_description='git-merge
+
+Do not overwrite changes.'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit c0 c0.c &&
+	test_commit c1 c1.c &&
+	test_commit c1a c1.c "c1 a" &&
+	git reset --hard c0 &&
+	test_commit c2 c2.c &&
+	git reset --hard c0 &&
+	mkdir sub &&
+	echo "sub/f" > sub/f &&
+	mkdir sub2 &&
+	echo "sub2/f" > sub2/f &&
+	git add sub/f sub2/f &&
+	git commit -m sub &&
+	git tag sub &&
+	echo "VERY IMPORTANT CHANGES" > important
+'
+
+test_expect_success 'will not overwrite untracked file' '
+	git reset --hard c1 &&
+	cp important c2.c &&
+	test_must_fail git merge c2 &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important c2.c
+'
+
+test_expect_success 'will overwrite tracked file' '
+	git reset --hard c1 &&
+	cp important c2.c &&
+	git add c2.c &&
+	git commit -m important &&
+	git checkout c2
+'
+
+test_expect_success 'will not overwrite new file' '
+	git reset --hard c1 &&
+	cp important c2.c &&
+	git add c2.c &&
+	test_must_fail git merge c2 &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important c2.c
+'
+
+test_expect_success 'will not overwrite staged changes' '
+	git reset --hard c1 &&
+	cp important c2.c &&
+	git add c2.c &&
+	rm c2.c &&
+	test_must_fail git merge c2 &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	git checkout c2.c &&
+	test_cmp important c2.c
+'
+
+test_expect_success 'will not overwrite removed file' '
+	git reset --hard c1 &&
+	git rm c1.c &&
+	git commit -m "rm c1.c" &&
+	cp important c1.c &&
+	test_must_fail git merge c1a &&
+	test_cmp important c1.c
+'
+
+test_expect_success 'will not overwrite re-added file' '
+	git reset --hard c1 &&
+	git rm c1.c &&
+	git commit -m "rm c1.c" &&
+	cp important c1.c &&
+	git add c1.c &&
+	test_must_fail git merge c1a &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important c1.c
+'
+
+test_expect_success 'will not overwrite removed file with staged changes' '
+	git reset --hard c1 &&
+	git rm c1.c &&
+	git commit -m "rm c1.c" &&
+	cp important c1.c &&
+	git add c1.c &&
+	rm c1.c &&
+	test_must_fail git merge c1a &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	git checkout c1.c &&
+	test_cmp important c1.c
+'
+
+test_expect_success 'will not overwrite untracked subtree' '
+	git reset --hard c0 &&
+	rm -rf sub &&
+	mkdir -p sub/f &&
+	cp important sub/f/important &&
+	test_must_fail git merge sub &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important sub/f/important
+'
+
+cat >expect <<\EOF
+error: The following untracked working tree files would be overwritten by merge:
+	sub
+	sub2
+Please move or remove them before you can merge.
+EOF
+
+test_expect_success 'will not overwrite untracked file in leading path' '
+	git reset --hard c0 &&
+	rm -rf sub &&
+	cp important sub &&
+	cp important sub2 &&
+	test_must_fail git merge sub 2>out &&
+	test_cmp out expect &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important sub &&
+	test_cmp important sub2 &&
+	rm -f sub sub2
+'
+
+test_expect_failure SYMLINKS 'will not overwrite untracked symlink in leading path' '
+	git reset --hard c0 &&
+	rm -rf sub &&
+	mkdir sub2 &&
+	ln -s sub2 sub &&
+	test_must_fail git merge sub &&
+	test_path_is_missing .git/MERGE_HEAD
+'
+
+test_expect_success SYMLINKS 'will not be confused by symlink in leading path' '
+	git reset --hard c0 &&
+	rm -rf sub &&
+	ln -s sub2 sub &&
+	git add sub &&
+	git commit -m ln &&
+	git checkout sub
+'
+
+cat >expect <<\EOF
+error: Untracked working tree file 'c0.c' would be overwritten by merge.
+fatal: read-tree failed
+EOF
+
+test_expect_success 'will not overwrite untracked file on unborn branch' '
+	git reset --hard c0 &&
+	git rm -fr . &&
+	git checkout --orphan new &&
+	cp important c0.c &&
+	test_must_fail git merge c0 2>out &&
+	test_cmp out expect &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important c0.c
+'
+
+test_done