fork_database don't assert on last pop_block during DB close

libraries/chain/db_block.cpp

@@ -585,14 +585,16 @@ signed_block database::_generate_block(
  * Removes the most recent block from the database and
  * undoes any changes it made.
  */
-void database::pop_block()
+void database::pop_block(bool check)
 { try {
    _pending_tx_session.reset();
    auto head_id = head_block_id();
    optional<signed_block> head_block = fetch_block_by_id( head_id );
    GRAPHENE_ASSERT( head_block.valid(), pop_empty_chain, "there are no blocks to pop" );
 
-   _fork_db.pop_block();
+   ilog( "head_block is ${dump}", ("dump", head_block) );
+
+   _fork_db.pop_block(check);
    pop_undo();
 
    _popped_tx.insert( _popped_tx.begin(), head_block->transactions.begin(), head_block->transactions.end() );

libraries/chain/db_management.cpp

@@ -259,11 +259,12 @@ void database::close(bool rewind)
       try
       {
          uint32_t cutoff = get_dynamic_global_properties().last_irreversible_block_num;
-
+         //ilog("cutoff = ${c}", ("c", cutoff));
          while( head_block_num() > cutoff )
          {
+	    //ilog("head_block_num() = ${id}", ("id", head_block_num()));
             block_id_type popped_block_id = head_block_id();
-            pop_block();
+            pop_block( head_block_num() == cutoff + 1 ? false : true);
             _fork_db.remove(popped_block_id); // doesn't throw on missing
          }
       }

libraries/chain/fork_database.cpp

@@ -35,11 +35,13 @@ void fork_database::reset()
    _index.clear();
 }
 
-void fork_database::pop_block()
+void fork_database::pop_block(bool check)
 {
    FC_ASSERT( _head, "no blocks to pop" );
    auto prev = _head->prev.lock();
-   FC_ASSERT( prev, "poping block would leave head block null" );
+   if (check){
+       FC_ASSERT( prev, "poping block would leave head block null" );
+   }
     _head = prev;
 }
 

libraries/chain/include/graphene/chain/database.hpp

@@ -163,7 +163,7 @@ namespace graphene { namespace chain {
             const fc::ecc::private_key& block_signing_private_key
             );
 
-         void pop_block();
+         void pop_block(bool check = true);
          void clear_pending();
 
          /**

libraries/chain/include/graphene/chain/fork_database.hpp

@@ -92,7 +92,7 @@ namespace graphene { namespace chain {
           */
          shared_ptr<fork_item>            push_block(const signed_block& b);
          shared_ptr<fork_item>            head()const { return _head; }
-         void                             pop_block();
+         void                             pop_block(bool check);
 
          /**
           *  Given two head blocks, return two branches of the fork graph that