json_object_deep_copy: fix deep copy of strings containing '\0'

json_object.c

@@ -1388,7 +1388,7 @@ int json_c_shallow_copy_default(json_object *src, json_object *parent, const cha
 		break;
 
 	case json_type_string:
-		*dst = json_object_new_string(get_string_component(src));
+		*dst = json_object_new_string_len(get_string_component(src), src->o.c_string.len);
 		break;
 
 	case json_type_object:

tests/test_deep_copy.c

@@ -18,6 +18,7 @@ static const char *json_str1 =
 "        \"GlossDiv\": {"
 "            \"title\": \"S\","
 "            \"null_obj\": null, "
+"            \"null_str\": \" \\u0000 \","
 "            \"GlossList\": {"
 "                \"GlossEntry\": {"
 "                    \"ID\": \"SGML\","

tests/test_deep_copy.expected

@@ -13,6 +13,7 @@ Printing JSON objects for visual inspection
     "GlossDiv":{
       "title":"S",
       "null_obj":null,
+      "null_str":" \u0000 ",
       "GlossList":{
         "GlossEntry":{
           "ID":"SGML",