Handle gap_epoch_open_pending block status (#4821)

nano/lib/stats_enums.hpp

@@ -528,6 +528,7 @@ enum class detail
 	blocking_overflow,
 	priority_insert,
 	priority_set,
+	priority_erase,
 	priority_unblocked,
 	erase_by_threshold,
 	erase_by_blocking,

nano/node/bootstrap/account_sets.cpp

@@ -104,6 +104,19 @@ void nano::bootstrap::account_sets::priority_set (nano::account const & account,
 	}
 }
 
+void nano::bootstrap::account_sets::priority_erase (nano::account const & account)
+{
+	if (account.is_zero ())
+	{
+		return;
+	}
+
+	if (priorities.get<tag_account> ().erase (account) > 0)
+	{
+		stats.inc (nano::stat::type::bootstrap_account_sets, nano::stat::detail::priority_erase);
+	}
+}
+
 void nano::bootstrap::account_sets::block (nano::account const & account, nano::block_hash const & dependency)
 {
 	debug_assert (!account.is_zero ());

nano/node/bootstrap/account_sets.hpp

@@ -33,18 +33,10 @@ class account_sets
 public:
 	account_sets (account_sets_config const &, nano::stats &);
 
-	/**
-	 * If an account is not blocked, increase its priority.
-	 * If the account does not exist in priority set and is not blocked, inserts a new entry.
-	 * Current implementation increases priority by 1.0f each increment
-	 */
 	void priority_up (nano::account const & account);
-	/**
-	 * Decreases account priority
-	 * Current implementation divides priority by 2.0f and saturates down to 1.0f.
-	 */
 	void priority_down (nano::account const & account);
 	void priority_set (nano::account const & account, double priority = priority_initial);
+	void priority_erase (nano::account const & account);
 
 	void block (nano::account const & account, nano::block_hash const & dependency);
 	void unblock (nano::account const & account, std::optional<nano::block_hash> const & hash = std::nullopt);

nano/node/bootstrap/bootstrap_service.cpp

@@ -326,7 +326,16 @@ void nano::bootstrap_service::inspect (secure::transaction const & tx, nano::blo
 			}
 		}
 		break;
+		case nano::block_status::gap_epoch_open_pending:
+		{
+			// Epoch open blocks for accounts that don't have any pending blocks yet
+			debug_assert (block.type () == block_type::state); // Only state blocks can have epoch open pending status
+			const auto account = block.account_field ().value_or (0);
+			accounts.priority_erase (account);
+		}
+		break;
 		default: // No need to handle other cases
+			// TODO: If we receive blocks that are invalid (bad signature, fork, etc.), we should penalize the peer that sent them
 			break;
 	}
 }