✅ add regression test #2824

test/src/unit-regression2.cpp

@@ -157,6 +157,26 @@ struct adl_serializer<NonDefaultConstructible>
 };
 } // namespace nlohmann
 
+/////////////////////////////////////////////////////////////////////
+// for #2824
+/////////////////////////////////////////////////////////////////////
+
+class sax_no_exception : public nlohmann::detail::json_sax_dom_parser<json>
+{
+  public:
+    explicit sax_no_exception(json& j) : nlohmann::detail::json_sax_dom_parser<json>(j, false) {}
+
+    static bool parse_error(std::size_t position, const std::string& last_token, const json::exception& ex)
+    {
+        error_string = ex.what();
+        return false;
+    }
+
+    static std::string error_string;
+};
+
+std::string sax_no_exception::error_string = "";
+
 
 TEST_CASE("regression tests 2")
 {
@@ -622,6 +642,15 @@ TEST_CASE("regression tests 2")
         }
     }
 
+    SECTION("issue #2824 - encoding of json::exception::what()")
+    {
+        json j;
+        sax_no_exception sax(j);
+
+        CHECK (!json::sax_parse("xyz", &sax));
+        CHECK(sax_no_exception::error_string == "[json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - invalid literal; last read: 'x'");
+    }
+
     SECTION("issue #2825 - Properly constrain the basic_json conversion operator")
     {
         static_assert(std::is_copy_assignable<nlohmann::ordered_json>::value, "");