From 2e390cb85edaf4e62e22063d29b402a499b10dc9 Mon Sep 17 00:00:00 2001
From: Romain Ruetschi <romain@informal.systems>
Date: Fri, 24 Nov 2023 10:01:48 +0100
Subject: [PATCH] Remove `NewRoundProposer` event in favor of check within the
 state machine (#79)

---
 Code/driver/src/driver.rs       | 10 +---------
 Code/round/src/events.rs        |  5 ++---
 Code/round/src/state_machine.rs |  5 ++++-
 Code/test/tests/round.rs        |  7 +++++--
 4 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/Code/driver/src/driver.rs b/Code/driver/src/driver.rs
index 86a86357b..966a1948a 100644
--- a/Code/driver/src/driver.rs
+++ b/Code/driver/src/driver.rs
@@ -121,17 +121,9 @@ where
         height: Ctx::Height,
         round: Round,
     ) -> Result<Option<RoundMessage<Ctx>>, Error<Ctx>> {
-        let proposer = self.get_proposer(round)?;
-
-        let event = if proposer.address() == &self.address {
-            RoundEvent::NewRoundProposer
-        } else {
-            RoundEvent::NewRound
-        };
-
         self.round_state = RoundState::new(height, round);
 
-        self.apply_event(round, event)
+        self.apply_event(round, RoundEvent::NewRound)
     }
 
     async fn apply_propose_value(
diff --git a/Code/round/src/events.rs b/Code/round/src/events.rs
index 544edfc00..77c6fff40 100644
--- a/Code/round/src/events.rs
+++ b/Code/round/src/events.rs
@@ -5,10 +5,9 @@ pub enum Event<Ctx>
 where
     Ctx: Context,
 {
-    NewRound,                                 // Start a new round, not as proposer.L20
-    NewRoundProposer, // Start a new round and wait for a value to propose.L14
+    NewRound,                 // Start a new round, either as proposer or not. L14/L20
     ProposeValue(Ctx::Value), // Propose a value.L14
-    Proposal(Ctx::Proposal), // Receive a proposal. L22 + L23 (valid)
+    Proposal(Ctx::Proposal),  // Receive a proposal. L22 + L23 (valid)
     ProposalAndPolkaPrevious(Ctx::Proposal), // Recieved a proposal and a polka value from a previous round. L28 + L29 (valid)
     ProposalInvalid,                         // Receive an invalid proposal. L26 + L32 (invalid)
     PolkaValue(ValueId<Ctx>),                // Receive +2/3 prevotes for valueId. L44
diff --git a/Code/round/src/state_machine.rs b/Code/round/src/state_machine.rs
index c77eda7b3..4dfa72308 100644
--- a/Code/round/src/state_machine.rs
+++ b/Code/round/src/state_machine.rs
@@ -63,9 +63,12 @@ where
 
     match (state.step, event) {
         // From NewRound. Event must be for current round.
-        (Step::NewRound, Event::NewRoundProposer) if this_round => {
+
+        // We are the proposer
+        (Step::NewRound, Event::NewRound) if this_round && info.is_proposer() => {
             propose_valid_or_get_value(state) // L18
         }
+        // We are not the proposer
         (Step::NewRound, Event::NewRound) if this_round => schedule_timeout_propose(state), // L11/L20
 
         // From Propose. Event must be for current round.
diff --git a/Code/test/tests/round.rs b/Code/test/tests/round.rs
index 9a14b692f..0952ff747 100644
--- a/Code/test/tests/round.rs
+++ b/Code/test/tests/round.rs
@@ -7,6 +7,7 @@ use malachite_round::state::{State, Step};
 use malachite_round::state_machine::{apply_event, Info};
 
 const ADDRESS: Address = Address::new([42; 20]);
+const OTHER_ADDRESS: Address = Address::new([21; 20]);
 
 #[test]
 fn test_propose() {
@@ -20,9 +21,10 @@ fn test_propose() {
         ..Default::default()
     };
 
+    // We are the proposer
     let data = Info::new(round, &ADDRESS, &ADDRESS);
 
-    let transition = apply_event(state.clone(), &data, Event::NewRoundProposer);
+    let transition = apply_event(state.clone(), &data, Event::NewRound);
 
     state.step = Step::Propose;
     assert_eq!(transition.next_state, state);
@@ -53,7 +55,8 @@ fn test_prevote() {
         ..Default::default()
     };
 
-    let data = Info::new(Round::new(1), &ADDRESS, &ADDRESS);
+    // We are not the proposer
+    let data = Info::new(Round::new(1), &ADDRESS, &OTHER_ADDRESS);
 
     let transition = apply_event(state, &data, Event::NewRound);