huskies: merge 664_story_crdt_lamport_clock_inner_seq_must_resume_from_max_own_author_seq_1_instead_of_resetting_to_1_on_restart_phase_c

crates/bft-json-crdt/src/list_crdt.rs

@@ -47,6 +47,21 @@ where
         }
     }
 
+    /// Returns the current Lamport sequence number for this list.
+    pub fn our_seq(&self) -> SequenceNumber {
+        self.our_seq
+    }
+
+    /// Advance the internal sequence counter to at least `seq`.
+    ///
+    /// After `advance_seq(n)`, the next local op will carry `seq = max(our_seq, n) + 1`
+    /// instead of the default `1`.  Used on restart to resume the Lamport clock
+    /// from the document-wide floor so that newly-created registers don't
+    /// re-emit low sequence numbers.
+    pub fn advance_seq(&mut self, seq: SequenceNumber) {
+        self.our_seq = max(self.our_seq, seq);
+    }
+
     /// Locally insert some content causally after the given operation
     pub fn insert<U: Into<JsonValue>>(&mut self, after: OpId, content: U) -> Op<JsonValue> {
         let mut op = Op::new(
@@ -365,6 +380,18 @@ mod test {
         assert_eq!(list.view(), vec![1, 4, 2, 3]);
     }
 
+    #[test]
+    fn test_advance_seq_resumes_from_floor() {
+        let mut list = ListCrdt::<i64>::new(make_author(1), vec![]);
+        list.advance_seq(100);
+        assert_eq!(list.our_seq(), 100);
+        let op = list.insert(ROOT_ID, 42);
+        assert_eq!(
+            op.seq, 101,
+            "first op after advance_seq(100) must have seq=101"
+        );
+    }
+
     #[test]
     fn test_list_idempotence() {
         let mut list = ListCrdt::<i64>::new(make_author(1), vec![]);