Use peers to check who to send Prepare to. Fix #156

Author: haraldng

omnipaxos/src/sequence_paxos/leader.rs

@@ -372,7 +372,7 @@ where
         match self.state.1 {
             Phase::Prepare => {
                 // Resend Prepare
-                let preparable_peers = self.leader_state.get_preparable_peers();
+                let preparable_peers = self.leader_state.get_preparable_peers(&self.peers);
                 for peer in preparable_peers {
                     self.send_prepare(peer);
                 }
@@ -392,7 +392,7 @@ where
                     }
                 }
                 // Resend Prepare
-                let preparable_peers = self.leader_state.get_preparable_peers();
+                let preparable_peers = self.leader_state.get_preparable_peers(&self.peers);
                 for peer in preparable_peers {
                     self.send_prepare(peer);
                 }

omnipaxos/src/util.rs

@@ -208,13 +208,15 @@ where
     }
 
     /// The pids of peers which have not promised a higher ballot than mine.
-    pub fn get_preparable_peers(&self) -> Vec<NodeId> {
-        self.promises_meta
+    pub(crate) fn get_preparable_peers(&self, peers: &[NodeId]) -> Vec<NodeId> {
+        peers
             .iter()
-            .enumerate()
-            .filter_map(|(idx, x)| match x {
-                PromiseState::NotPromised => Some((idx + 1) as NodeId),
-                _ => None,
+            .filter_map(|pid| {
+                let idx = Self::pid_to_idx(*pid);
+                match self.promises_meta.get(idx).unwrap() {
+                    PromiseState::NotPromised => Some(*pid),
+                    _ => None,
+                }
             })
             .collect()
     }
@@ -467,3 +469,34 @@ pub(crate) struct AcceptedMetaData<T: Entry> {
     #[cfg(feature = "unicache")]
     pub entries: Vec<T::EncodeResult>,
 }
+
+#[cfg(not(feature = "unicache"))]
+#[cfg(test)]
+mod tests {
+    use super::*; // Import functions and types from this module
+    use crate::storage::NoSnapshot;
+    #[test]
+    fn preparable_peers_test() {
+        type Value = ();
+
+        impl Entry for Value {
+            type Snapshot = NoSnapshot;
+        }
+
+        let nodes = vec![6, 7, 8];
+        let quorum = Quorum::Majority(2);
+        let max_pid = 8;
+        let leader_state =
+            LeaderState::<Value>::with(Ballot::with(1, 1, 1, max_pid), max_pid as usize, quorum);
+        let prep_peers = leader_state.get_preparable_peers(&nodes);
+        assert_eq!(prep_peers, nodes);
+
+        let nodes = vec![7, 1, 100, 4, 6];
+        let quorum = Quorum::Majority(3);
+        let max_pid = 100;
+        let leader_state =
+            LeaderState::<Value>::with(Ballot::with(1, 1, 1, max_pid), max_pid as usize, quorum);
+        let prep_peers = leader_state.get_preparable_peers(&nodes);
+        assert_eq!(prep_peers, nodes);
+    }
+}