check feature names for special JSON chars (#2557)

include/LightGBM/dataset.h

@@ -561,7 +561,11 @@ class Dataset {
     for (auto& feature_name : feature_names_) {
       // check ascii
       if (!Common::CheckASCII(feature_name)) {
-        Log::Fatal("Do not support non-ascii characters in feature name.");
+        Log::Fatal("Do not support non-ASCII characters in feature name.");
+      }
+      // check json
+      if (!Common::CheckAllowedJSON(feature_name)) {
+        Log::Fatal("Do not support special JSON characters in feature name.");
       }
       if (feature_name.find(' ') != std::string::npos) {
         spaceInFeatureName = true;

include/LightGBM/utils/common.h

@@ -927,6 +927,24 @@ inline bool CheckASCII(const std::string& s) {
   return true;
 }
 
+inline bool CheckAllowedJSON(const std::string& s) {
+  unsigned char char_code;
+  for (auto c : s) {
+    char_code = static_cast<unsigned char>(c);
+    if (char_code == 34      // "
+        || char_code == 44   // ,
+        || char_code == 58   // :
+        || char_code == 91   // [
+        || char_code == 93   // ]
+        || char_code == 123  // {
+        || char_code == 125  // }
+        ) {
+      return false;
+    }
+  }
+  return true;
+}
+
 }  // namespace Common
 
 }  // namespace LightGBM

src/io/config.cpp

@@ -21,7 +21,7 @@ void Config::KV2Map(std::unordered_map<std::string, std::string>* params, const
       value = Common::RemoveQuotationSymbol(Common::Trim(tmp_strs[1]));
     }
     if (!Common::CheckASCII(key) || !Common::CheckASCII(value)) {
-      Log::Fatal("Do not support non-ascii characters in config.");
+      Log::Fatal("Do not support non-ASCII characters in config.");
     }
     if (key.size() > 0) {
       auto value_search = params->find(key);