#387 - change number of active SONs via vote

libraries/chain/account_evaluator.cpp

@@ -67,6 +67,9 @@ void verify_account_votes( const database& db, const account_options& options )
    FC_ASSERT( options.num_committee <= chain_params.maximum_committee_count,
               "Voted for more committee members than currently allowed (${c})", ("c", chain_params.maximum_committee_count) );
    FC_ASSERT( db.find_object(options.voting_account), "Invalid proxy account specified." );
+   FC_ASSERT( chain_params.extensions.value.maximum_son_count.valid() , "Invalid maximum son count" );
+   FC_ASSERT( options.num_son <= *chain_params.extensions.value.maximum_son_count,
+             "Voted for more sons than currently allowed (${c})", ("c", *chain_params.extensions.value.maximum_son_count) );
 
    uint32_t max_vote_id = gpo.next_available_vote_id;
    bool has_worker_votes = false;

libraries/chain/db_maint.cpp

@@ -182,7 +182,21 @@ void database::pay_sons()
    const dynamic_global_property_object& dpo = get_dynamic_global_properties();
    // Current requirement is that we have to pay every 24 hours, so the following check
    if( dpo.son_budget.value > 0 && ((now - dpo.last_son_payout_time) >= fc::seconds(get_global_properties().parameters.son_pay_time()))) {
-      auto sons = sort_votable_objects<son_index>(get_global_properties().parameters.maximum_son_count());
+      assert( _son_count_histogram_buffer.size() > 0 );
+      const share_type  stake_target = (_total_voting_stake-_son_count_histogram_buffer[0]) / 2;
+      /// accounts that vote for 0 or 1 son do not get to express an opinion on
+      /// the number of sons to have (they abstain and are non-voting accounts)
+      share_type stake_tally = 0;
+      size_t son_count = 0;
+      if( stake_target > 0 )
+      {
+         while( (son_count < _son_count_histogram_buffer.size() - 1)
+                && (stake_tally <= stake_target) )
+         {
+            stake_tally += _son_count_histogram_buffer[++son_count];
+         }
+      }
+      auto sons = sort_votable_objects<son_index>(std::max(son_count*2+1, (size_t)get_chain_properties().immutable_parameters.min_son_count));
       // After SON2 HF
       uint64_t total_votes = 0;
       for( const son_object& son : sons )
@@ -679,8 +693,7 @@ void database::update_active_sons()
    }
 
    const global_property_object& gpo = get_global_properties();
-   const chain_parameters& cp = gpo.parameters;
-   auto sons = sort_votable_objects<son_index>(cp.maximum_son_count());
+   auto sons = sort_votable_objects<son_index>(std::max(son_count*2+1, (size_t)get_chain_properties().immutable_parameters.min_son_count));
 
    const auto& all_sons = get_index_type<son_index>().indices();
 
@@ -2041,6 +2054,13 @@ void update_son_params(database& db)
          gpo.parameters.extensions.value.maximum_son_count = 7;
       });
    }
+   else
+   {
+      const auto& gpo = db.get_global_properties();
+      db.modify( gpo, []( global_property_object& gpo ) {
+         gpo.parameters.extensions.value.maximum_son_count = GRAPHENE_DEFAULT_MAX_SONS;
+      });
+   }
 }
 
 void database::perform_chain_maintenance(const signed_block& next_block, const global_property_object& global_props)

tests/cli/son.cpp

@@ -337,7 +337,8 @@ BOOST_FIXTURE_TEST_CASE( select_top_fifteen_sons, cli_fixture )
       global_property_object gpo;
 
       gpo = con.wallet_api_ptr->get_global_properties();
-      unsigned int son_number = gpo.parameters.maximum_son_count();
+      //! Set son number as 5 (as the begining son count)
+      unsigned int son_number = 5;
 
       flat_map<sidechain_type, string> sidechain_public_keys;
 
@@ -400,7 +401,7 @@ BOOST_FIXTURE_TEST_CASE( select_top_fifteen_sons, cli_fixture )
       BOOST_TEST_MESSAGE("gpo: " << gpo.active_sons.size());
       BOOST_CHECK(generate_maintenance_block());
 
-      BOOST_CHECK(gpo.active_sons.size() == gpo.parameters.maximum_son_count());
+      BOOST_CHECK(gpo.active_sons.size() == son_number);
 
    } catch( fc::exception& e ) {
       BOOST_TEST_MESSAGE("SON cli wallet tests exception");
@@ -644,7 +645,8 @@ BOOST_FIXTURE_TEST_CASE( cli_list_active_sons, cli_fixture )
       global_property_object gpo;
 
       gpo = con.wallet_api_ptr->get_global_properties();
-      unsigned int son_number = gpo.parameters.maximum_son_count();
+      //! Set son number as 5 (as the begining son count)
+      unsigned int son_number = 5;
 
       flat_map<sidechain_type, string> sidechain_public_keys;
 

tests/tests/block_tests.cpp

@@ -1040,11 +1040,8 @@ BOOST_FIXTURE_TEST_CASE( hardfork_son2_time, database_fixture )
 
    generate_blocks(HARDFORK_SON3_TIME);
    // after this hardfork maximum son account should not reset the value
-   // on 7 after maintenance interval anymore. So change the global parameters
-   // and check the value after maintenance interval
-   db.modify(db.get_global_properties(), [](global_property_object& p) {
-      p.parameters.extensions.value.maximum_son_count = 13;
-   });
+   // on 7 after maintenance interval anymore. It must be GRAPHENE_DEFAULT_MAX_SONS
+   BOOST_CHECK_EQUAL(db.get_global_properties().parameters.maximum_son_count(), GRAPHENE_DEFAULT_MAX_SONS);
 
    generate_blocks(db.get_dynamic_global_properties().next_maintenance_time);
    generate_block();