Don't overwrite ~ files checking out conflicts

If a D/F conflict or rename 2->1 conflict occurs,
we write the file sides as filename~branchname.  If
a file with that name already exists in the working
directory, write as filename~branchname_0 instead.
(Incrementing 0 until a unique filename is found.)

1 files changed, 140 insertions, 0 deletions

diff --git a/tests-clar/checkout/conflict.c b/tests-clar/checkout/conflict.c
index da4a20fd8..8b6dd4cd8 100644
--- a/tests-clar/checkout/conflict.c
+++ b/tests-clar/checkout/conflict.c
@@ -834,3 +834,143 @@ void test_checkout_conflict__rename_keep_ours(void)
 	ensure_workdir("7-both-renamed.txt",
 				   0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11");
 }
+
+void test_checkout_conflict__name_mangled_file_exists_in_workdir(void)
+{
+	git_checkout_opts opts = GIT_CHECKOUT_OPTS_INIT;
+
+	struct checkout_index_entry checkout_index_entries[] = {
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 1, "test-one-side-one.txt" },
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 3, "test-one-side-one.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 1, "test-one-side-two.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 2, "test-one-side-two.txt" },
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 2, "test-one.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 3, "test-one.txt" },
+
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 1, "test-two-side-one.txt" },
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 3, "test-two-side-one.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 1, "test-two-side-two.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 2, "test-two-side-two.txt" },
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 2, "test-two.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 3, "test-two.txt" },
+
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 1, "test-three-side-one.txt" },
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 3, "test-three-side-one.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 1, "test-three-side-two.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 2, "test-three-side-two.txt" },
+		{ 0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11", 2, "test-three.txt" },
+		{ 0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07", 3, "test-three.txt" },
+
+		{ 0100644, CONFLICTING_ANCESTOR_OID, 1, "directory_file-one" },
+		{ 0100644, CONFLICTING_OURS_OID, 2, "directory_file-one" },
+		{ 0100644, CONFLICTING_THEIRS_OID, 0, "directory_file-one/file" },
+
+		{ 0100644, CONFLICTING_ANCESTOR_OID, 1, "directory_file-two" },
+		{ 0100644, CONFLICTING_OURS_OID, 0, "directory_file-two/file" },
+		{ 0100644, CONFLICTING_THEIRS_OID, 3, "directory_file-two" },
+	};
+
+	struct checkout_name_entry checkout_name_entries[] = {
+		{
+			"test-one-side-one.txt",
+			"test-one.txt",
+			"test-one-side-one.txt"
+		},
+		{
+			"test-one-side-two.txt",
+			"test-one-side-two.txt",
+			"test-one.txt"
+		},
+
+		{
+			"test-two-side-one.txt",
+			"test-two.txt",
+			"test-two-side-one.txt"
+		},
+		{
+			"test-two-side-two.txt",
+			"test-two-side-two.txt",
+			"test-two.txt"
+		},
+
+		{
+			"test-three-side-one.txt",
+			"test-three.txt",
+			"test-three-side-one.txt"
+		},
+		{
+			"test-three-side-two.txt",
+			"test-three-side-two.txt",
+			"test-three.txt"
+		}
+	};
+
+	opts.checkout_strategy |= GIT_CHECKOUT_SAFE;
+
+	create_index(checkout_index_entries, 24);
+	create_index_names(checkout_name_entries, 6);
+	git_index_write(g_index);
+
+	/* Add some files on disk that conflict with the names that would be chosen
+	 * for the files written for each side. */
+
+	cl_git_rewritefile("merge-resolve/test-one.txt~ours",
+		"Expect index contents to be written to ~ours_0");
+	cl_git_rewritefile("merge-resolve/test-one.txt~theirs",
+		"Expect index contents to be written to ~theirs_0");
+
+	cl_git_rewritefile("merge-resolve/test-two.txt~ours",
+		"Expect index contents to be written to ~ours_3");
+	cl_git_rewritefile("merge-resolve/test-two.txt~theirs",
+		"Expect index contents to be written to ~theirs_3");
+	cl_git_rewritefile("merge-resolve/test-two.txt~ours_0",
+		"Expect index contents to be written to ~ours_3");
+	cl_git_rewritefile("merge-resolve/test-two.txt~theirs_0",
+		"Expect index contents to be written to ~theirs_3");
+	cl_git_rewritefile("merge-resolve/test-two.txt~ours_1",
+		"Expect index contents to be written to ~ours_3");
+	cl_git_rewritefile("merge-resolve/test-two.txt~theirs_1",
+		"Expect index contents to be written to ~theirs_3");
+	cl_git_rewritefile("merge-resolve/test-two.txt~ours_2",
+		"Expect index contents to be written to ~ours_3");
+	cl_git_rewritefile("merge-resolve/test-two.txt~theirs_2",
+		"Expect index contents to be written to ~theirs_3");
+
+	cl_git_rewritefile("merge-resolve/test-three.txt~Ours",
+		"Expect case insensitive filesystems to create ~ours_0");
+	cl_git_rewritefile("merge-resolve/test-three.txt~THEIRS",
+		"Expect case insensitive filesystems to create ~theirs_0");
+
+	cl_git_rewritefile("merge-resolve/directory_file-one~ours",
+		"Index contents written to ~ours_0 in this D/F conflict");
+	cl_git_rewritefile("merge-resolve/directory_file-two~theirs",
+		"Index contents written to ~theirs_0 in this D/F conflict");
+
+	cl_git_pass(git_checkout_index(g_repo, g_index, &opts));
+
+	ensure_workdir("test-one.txt~ours_0",
+		0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11");
+	ensure_workdir("test-one.txt~theirs_0",
+		0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07");
+
+	ensure_workdir("test-two.txt~ours_3",
+		0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11");
+	ensure_workdir("test-two.txt~theirs_3",
+		0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07");
+
+	/* Name is mangled on case insensitive only */
+#if defined(GIT_WIN32) || defined(__APPLE__)
+	ensure_workdir("test-three.txt~ours_0",
+		0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11");
+	ensure_workdir("test-three.txt~theirs_0",
+		0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07");
+#else
+	ensure_workdir("test-three.txt~ours",
+		0100644, "b42712cfe99a1a500b2a51fe984e0b8a7702ba11");
+	ensure_workdir("test-three.txt~theirs",
+		0100644, "b69fe837e4cecfd4c9a40cdca7c138468687df07");
+#endif
+
+	ensure_workdir("directory_file-one~ours_0", 0100644, CONFLICTING_OURS_OID);
+	ensure_workdir("directory_file-two~theirs_0", 0100644, CONFLICTING_THEIRS_OID);
+}