Retaining historical blocks until election completion. history::votes…

… filters by root+hash so it won't pick up votes for hashes it's not looking for.

nano/node/blockprocessor.cpp

@@ -305,7 +305,6 @@ void nano::block_processor::process_batch (nano::unique_lock<std::mutex> & lock_
 					// Deleting from votes cache & wallet work watcher, stop active transaction
 					for (auto & i : rollback_list)
 					{
-						node.history.erase (i->root ());
 						node.wallets.watcher->remove (*i);
 						// Stop all rolled back active transactions except initial
 						if (i->hash () != successor->hash ())

nano/node/election.cpp

@@ -32,6 +32,11 @@ qualified_root (block_a->qualified_root ())
 	last_blocks.emplace (block_a->hash (), block_a);
 }
 
+nano::election::~election()
+{
+	node.history.erase (root);
+}
+
 void nano::election::confirm_once (nano::unique_lock<std::mutex> & lock_a, nano::election_status_type type_a)
 {
 	debug_assert (lock_a.owns_lock ());
@@ -519,8 +524,6 @@ void nano::election::remove_votes (nano::block_hash const & hash_a)
 		{
 			last_votes.erase (vote->account);
 		}
-		// Clear votes cache
-		node.history.erase (root);
 	}
 }
 

nano/node/election.hpp

@@ -103,6 +103,7 @@ class election final : public std::enable_shared_from_this<nano::election>
 
 public: // Interface
 	election (nano::node &, std::shared_ptr<nano::block>, std::function<void(std::shared_ptr<nano::block>)> const &, bool, nano::election_behavior);
+	~election ();
 	std::shared_ptr<nano::block> find (nano::block_hash const &) const;
 	nano::election_vote_result vote (nano::account const &, uint64_t, nano::block_hash const &);
 	bool publish (std::shared_ptr<nano::block> const & block_a);