From dd5b7708b4f3c22ba70b5f077250917f6dadb9d5 Mon Sep 17 00:00:00 2001
From: Daniel Larimer <dlarimer@invictus-innovations.com>
Date: Sun, 3 Jan 2016 20:40:21 -0500
Subject: [PATCH] potential fix for hung chain

---
 libraries/chain/db_block.cpp                                | 5 ++++-
 libraries/chain/db_update.cpp                               | 6 ++++++
 libraries/chain/include/graphene/chain/database.hpp         | 3 ++-
 .../chain/include/graphene/chain/protocol/asset_ops.hpp     | 4 +++-
 4 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/libraries/chain/db_block.cpp b/libraries/chain/db_block.cpp
index 770951b6..ceb9d4be 100644
--- a/libraries/chain/db_block.cpp
+++ b/libraries/chain/db_block.cpp
@@ -548,7 +548,10 @@ processed_transaction database::apply_transaction(const signed_transaction& trx,
 processed_transaction database::_apply_transaction(const signed_transaction& trx)
 { try {
    uint32_t skip = get_node_properties().skip_flags;
-   trx.validate();
+
+   if( !(skip&skip_validate) )
+      trx.validate();
+
    auto& trx_idx = get_mutable_index_type<transaction_index>();
    const chain_id_type& chain_id = get_chain_id();
    auto trx_id = trx.id();
diff --git a/libraries/chain/db_update.cpp b/libraries/chain/db_update.cpp
index 2b6ba2e7..37c0a5de 100644
--- a/libraries/chain/db_update.cpp
+++ b/libraries/chain/db_update.cpp
@@ -348,6 +348,12 @@ void database::clear_expired_orders()
             assert(itr != call_index.end() && itr->debt_type() == mia_object.get_id());
             asset max_settlement = max_settlement_volume - settled;
 
+            if( order.balance.amount == 0 )
+            {
+               wlog( "0 settlement detected" );
+               cancel_order( order );
+               break;
+            }
             try {
                settled += match(*itr, order, settlement_price, max_settlement);
             } 
diff --git a/libraries/chain/include/graphene/chain/database.hpp b/libraries/chain/include/graphene/chain/database.hpp
index c44e687d..9326004c 100644
--- a/libraries/chain/include/graphene/chain/database.hpp
+++ b/libraries/chain/include/graphene/chain/database.hpp
@@ -70,7 +70,8 @@ namespace graphene { namespace chain {
             skip_merkle_check           = 1 << 7,  ///< used while reindexing
             skip_assert_evaluation      = 1 << 8,  ///< used while reindexing
             skip_undo_history_check     = 1 << 9,  ///< used while reindexing
-            skip_witness_schedule_check = 1 << 10  ///< used whiel reindexing
+            skip_witness_schedule_check = 1 << 10,  ///< used while reindexing
+            skip_validate               = 1 << 11 ///< used prior to checkpoint, skips validate() call on transaction
          };
 
          /**
diff --git a/libraries/chain/include/graphene/chain/protocol/asset_ops.hpp b/libraries/chain/include/graphene/chain/protocol/asset_ops.hpp
index 154c599d..13376053 100644
--- a/libraries/chain/include/graphene/chain/protocol/asset_ops.hpp
+++ b/libraries/chain/include/graphene/chain/protocol/asset_ops.hpp
@@ -225,7 +225,9 @@ namespace graphene { namespace chain {
       extensions_type extensions;
 
       account_id_type fee_payer()const { return account; }
-      void            validate()const {}
+      void            validate()const {
+         FC_ASSERT( amount.amount > 0, "Must settle at least 1 unit" );
+      }
 
       share_type calculate_fee(const fee_parameters_type& params)const
       { return 0; }