<filesystem>: create_directories() should throw for empty paths (#1285)

stl/inc/filesystem

@@ -3750,6 +3750,11 @@ namespace filesystem {
 
     // FUNCTION create_directories
     inline bool create_directories(const path& _Path, error_code& _Ec) {
+        if (_Path.empty()) {
+            _Ec = _Make_ec(__std_win_error::_Path_not_found);
+            return false;
+        }
+
         _Ec.clear(); // for exception safety
         const wstring& _Text = _Path.native();
         wstring _Tmp;

tests/std/tests/P0218R1_filesystem/test.cpp

@@ -3669,6 +3669,11 @@ void test_create_dirs_and_remove_all() {
     remove_all(badPath, ec);
     EXPECT(good(ec));
 
+    // test GH-1283 create_directories() should throw for empty paths
+    EXPECT(throws_filesystem_error([] { create_directories(path{}); }, "create_directories", path{}));
+    EXPECT(create_directories(path{}, ec) == false);
+    EXPECT(bad(ec));
+
     // test that normalization isn't done first
     auto dots = r / L"a/../b/../c"sv;
     EXPECT(create_directories(dots));