#387 Allow changing number of SONs by voting, similar to witnesses

libraries/app/application.cpp

@@ -454,7 +454,7 @@ public:
                              std::vector<fc::uint160_t> &contained_transaction_message_ids) override {
 
       // check point for the threads which may be cancled on application shutdown
-      if(!_running.load()) {
+      if (!_running.load()) {
          return true;
       }
 

libraries/chain/account_evaluator.cpp

@@ -62,11 +62,14 @@ void verify_account_votes( const database& db, const account_options& options )
    const auto& gpo = db.get_global_properties();
    const auto& chain_params = gpo.parameters;
 
+   FC_ASSERT( db.find_object(options.voting_account), "Invalid proxy account specified." );
+
    FC_ASSERT( options.num_witness <= chain_params.maximum_witness_count,
               "Voted for more witnesses than currently allowed (${c})", ("c", chain_params.maximum_witness_count) );
    FC_ASSERT( options.num_committee <= chain_params.maximum_committee_count,
               "Voted for more committee members than currently allowed (${c})", ("c", chain_params.maximum_committee_count) );
-   FC_ASSERT( db.find_object(options.voting_account), "Invalid proxy account specified." );
+   FC_ASSERT( options.num_son() <= chain_params.maximum_son_count(),
+             "Voted for more sons than currently allowed (${c})", ("c", chain_params.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 +182,26 @@ 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];
+         }
+      }
+      const vector<std::reference_wrapper<const son_object>> sons = [this, &son_count]{
+         if(head_block_time() >= HARDFORK_SON3_TIME)
+            return sort_votable_objects<son_index>(std::max(son_count*2+1, (size_t)get_chain_properties().immutable_parameters.min_son_count));
+         else
+            return sort_votable_objects<son_index>(get_global_properties().parameters.maximum_son_count());
+      }();
       // After SON2 HF
       uint64_t total_votes = 0;
       for( const son_object& son : sons )
@@ -683,8 +702,12 @@ void database::update_active_sons()
    }
 
    const global_property_object& gpo = get_global_properties();
-   const chain_parameters& cp = gpo.parameters;
+   const vector<std::reference_wrapper<const son_object>> sons = [this, &son_count]{
-   auto sons = sort_votable_objects<son_index>(cp.maximum_son_count());
+      if(head_block_time() >= HARDFORK_SON3_TIME)
+         return sort_votable_objects<son_index>(std::max(son_count*2+1, (size_t)get_chain_properties().immutable_parameters.min_son_count));
+      else
+         return sort_votable_objects<son_index>(get_global_properties().parameters.maximum_son_count());
+   }();
 
    const auto& all_sons = get_index_type<son_index>().indices();
 
@@ -2041,6 +2064,13 @@ 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)
@@ -2167,9 +2197,9 @@ void database::perform_chain_maintenance(const signed_block& next_block, const g
                // same rationale as for witnesses
                d._committee_count_histogram_buffer[offset] += voting_stake;
             }
-            if( opinion_account.options.num_son <= props.parameters.maximum_son_count() )
+            if( opinion_account.options.num_son() <= props.parameters.maximum_son_count() )
             {
-               uint16_t offset = std::min(size_t(opinion_account.options.num_son/2),
+               uint16_t offset = std::min(size_t(opinion_account.options.num_son()/2),
                                           d._son_count_histogram_buffer.size() - 1);
                // votes for a number greater than maximum_son_count
                // are turned into votes for maximum_son_count.
@@ -2271,6 +2301,7 @@ void database::perform_chain_maintenance(const signed_block& next_block, const g
          // the following parameters are not allowed to be changed. So take what is in global property
          p.pending_parameters->extensions.value.hive_asset = p.parameters.extensions.value.hive_asset;
          p.pending_parameters->extensions.value.hbd_asset = p.parameters.extensions.value.hbd_asset;
+         p.pending_parameters->extensions.value.maximum_son_count = p.parameters.extensions.value.maximum_son_count;
          p.pending_parameters->extensions.value.btc_asset = p.parameters.extensions.value.btc_asset;
          p.pending_parameters->extensions.value.son_account = p.parameters.extensions.value.son_account;
          p.pending_parameters->extensions.value.gpos_period_start = p.parameters.extensions.value.gpos_period_start;

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

@@ -37,6 +37,11 @@ namespace graphene { namespace chain {
    /// These are the fields which can be updated by the active authority.
    struct account_options
    {
+      struct ext
+      {
+         optional< uint16_t > num_son = 0;
+      };
+
       /// 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.
@@ -54,11 +59,11 @@ namespace graphene { namespace chain {
       uint16_t num_committee = 0;
       /// 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
-      uint16_t num_son = 0;
+      uint16_t num_son() const { return extensions.value.num_son.valid() ? *extensions.value.num_son : 0; }
       /// This is the list of vote IDs this account votes for. The weight of these votes is determined by this
       /// account's balance of core asset.
       flat_set<vote_id_type> votes;
-      extensions_type        extensions;
+      extension< ext > extensions;
       
       /// Whether this account is voting
       inline bool is_voting() const
@@ -289,6 +294,7 @@ namespace graphene { namespace chain {
 
 } } // graphene::chain
 
+FC_REFLECT(graphene::chain::account_options::ext, (num_son) )
 FC_REFLECT(graphene::chain::account_options, (memo_key)(voting_account)(num_witness)(num_committee)(votes)(extensions))
 // FC_REFLECT_TYPENAME( graphene::chain::account_whitelist_operation::account_listing)
 FC_REFLECT_ENUM( graphene::chain::account_whitelist_operation::account_listing,

libraries/chain/protocol/account.cpp

@@ -174,7 +174,7 @@ void account_options::validate() const
 {
    auto needed_witnesses = num_witness;
    auto needed_committee = num_committee;
-   auto needed_sons = num_son;
+   auto needed_sons = num_son();
 
    for( vote_id_type id : votes )
       if( id.type() == vote_id_type::witness && needed_witnesses )

libraries/wallet/wallet.cpp

@@ -2875,7 +2875,7 @@ public:
          if (!votes_removed)
             FC_THROW("Account ${account} is already not voting for SON ${son}", ("account", voting_account)("son", son));
       }
-      voting_account_object.options.num_son = desired_number_of_sons;
+      voting_account_object.options.extensions.value.num_son = desired_number_of_sons;
 
       account_update_operation account_update_op;
       account_update_op.account = voting_account_object.id;

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

@@ -1040,16 +1040,13 @@ 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
+   // on 7 after maintenance interval anymore. It must be GRAPHENE_DEFAULT_MAX_SONS
-   // and check the value after maintenance interval
+   BOOST_CHECK_EQUAL(db.get_global_properties().parameters.maximum_son_count(), GRAPHENE_DEFAULT_MAX_SONS);
-   db.modify(db.get_global_properties(), [](global_property_object& p) {
-      p.parameters.extensions.value.maximum_son_count = 13;
-   });
 
    generate_blocks(db.get_dynamic_global_properties().next_maintenance_time);
    generate_block();
 
-   BOOST_CHECK_EQUAL(db.get_global_properties().parameters.maximum_son_count(), 13);
+   BOOST_CHECK_EQUAL(db.get_global_properties().parameters.maximum_son_count(), 15);
 
 } FC_LOG_AND_RETHROW() }