late messages don't flip peer's epoch back

1 files changed, 4 insertions, 0 deletions

diff --git a/src/document/replica.rs b/src/document/replica.rs
index e24f93c..db47223 100644
--- a/src/document/replica.rs
+++ b/src/document/replica.rs
@@ -86,6 +86,9 @@ impl fmt::Debug for Epoch {
 /// [`Replica::heads`].
 pub struct Replica {
     pub epoch: Epoch,
+    /// How many times this node changed epoch (switch, rejoin, abandoned rejoin) in this
+    /// run: messages carry it, so a late one can't flip a peer's view of our epoch back.
+    pub epoch_seq: u32,
     pub doc: AutoCommit,
     heads: Vec<ChangeHash>,
 }
@@ -94,6 +97,7 @@ impl Replica {
     pub fn new(epoch: Epoch, doc: AutoCommit) -> Self {
         let mut replica = Self {
             epoch,
+            epoch_seq: 0,
             doc,
             heads: Vec::new(),
         };