From b33d2f17abb4bb607fa81806bd4240f45259dfdd Mon Sep 17 00:00:00 2001
From: Julien Clement <julien.clement@epita.fr>
Date: Wed, 6 May 2020 21:03:24 +0200
Subject: [PATCH] Fix a possible case when president receive a last vote after
 receiving a voted from someone else for the same ballot

---
 src/legislator/legislator.cc | 7 ++++---
 src/legislator/legislator.hh | 2 ++
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/legislator/legislator.cc b/src/legislator/legislator.cc
index 94ca9b0..a35497e 100644
--- a/src/legislator/legislator.cc
+++ b/src/legislator/legislator.cc
@@ -10,13 +10,14 @@
 namespace paxos
 {
     Legislator::Legislator(const LegislatorConfig& config)
-        : config_(config), ledger(config.name)
+        : config_(config), ledger(config.name), has_started(false)
     {
         log("created legislator " + config.name, blue);
     }
 
     void Legislator::initiate_ballot()
     {
+        has_started = false;
         quorum_previous_votes.clear();
         int new_ballot_number = ledger.last_tried() + 1;
         ledger.set_last_tried(new_ballot_number);
@@ -92,8 +93,7 @@ namespace paxos
         int vote_decree = std::stoi(*message.get_header("decree"));
 
         unsigned int nb_legislators = legislators.size();
-        if (ballot != ledger.last_tried()
-                || quorum_previous_votes.size() > nb_legislators / 2)
+        if (ballot != ledger.last_tried() || has_started)
         {
             log("but it was discarded because ballot " + std::to_string(ballot)
                     + " is outdated, it is either no longer in treatment or already started"
@@ -117,6 +117,7 @@ namespace paxos
 
     void Legislator::receive_enough_last_vote()
     {
+        has_started = true;
         int ballot = ledger.last_tried();
         std::string ballot_str = std::to_string(ballot);
 
diff --git a/src/legislator/legislator.hh b/src/legislator/legislator.hh
index f4c6dad..8586170 100644
--- a/src/legislator/legislator.hh
+++ b/src/legislator/legislator.hh
@@ -40,8 +40,10 @@ namespace paxos
 
         void handle_message(Message message);
 
+    private:
         Ledger ledger;
         std::unordered_map<std::string, Vote> quorum_previous_votes;
+        bool has_started;
 
     };
     using shared_legislator = std::shared_ptr<Legislator>;