Do not overwrite value of account_options extension

libraries/chain/account_evaluator.cpp

@@ -193,7 +193,14 @@ object_id_type account_create_evaluator::do_apply( const account_create_operatio
 
       if (!obj.options.extensions.value.num_son.valid())
       {
-         obj.options.extensions.value = account_options::ext();
+         obj.options.extensions.value.num_son = []{
+                        flat_map<sidechain_type, uint16_t> num_son;
+                        for(const auto& active_sidechain_type : all_sidechain_types){
+                           num_son[active_sidechain_type] = 0;
+                        }
+                        return num_son;
+                     }();
+
       }
 
       obj.statistics = d.create<account_statistics_object>([&obj](account_statistics_object& s){
@@ -335,6 +342,19 @@ void_result account_update_evaluator::do_apply( const account_update_operation&
          a.top_n_control_flags = 0;
       }
       if( o.new_options ) a.options = *o.new_options;
+
+      if (!a.options.extensions.value.num_son.valid())
+      {
+         a.options.extensions.value.num_son = []{
+            flat_map<sidechain_type, uint16_t> num_son;
+            for(const auto& active_sidechain_type : all_sidechain_types){
+               num_son[active_sidechain_type] = 0;
+            }
+            return num_son;
+         }();
+
+      }
+
       if( o.extensions.value.owner_special_authority.valid() )
       {
          a.owner_special_authority = *(o.extensions.value.owner_special_authority);

libraries/chain/include/graphene/chain/protocol/account.hpp

@@ -36,21 +36,16 @@ namespace graphene { namespace chain {
    bool is_cheap_name( const string& n );
 
    /// These are the fields which can be updated by the active authority.
-   struct account_options
+   struct   account_options
    {
       struct ext
       {
          /// The number of active son members this account votes the blockchain should appoint
          /// Must not exceed the actual number of son members voted for in @ref votes
-         optional< flat_map<sidechain_type, uint16_t> > num_son = []{
-            flat_map<sidechain_type, uint16_t> num_son;
-            for(const auto& active_sidechain_type : all_sidechain_types){
-               num_son[active_sidechain_type] = 0;
-            }
-            return num_son;
-         }();
+         optional< flat_map<sidechain_type, uint16_t> > num_son;
       };
 
+
       /// The memo key is the key this account will typically use to encrypt/sign transaction memos and other non-
       /// validated account activities. This field is here to prevent confusion if the active authority has zero or
       /// multiple keys in it.