1 files changed, 16 insertions, 9 deletions

diff --git a/src/document/changes.rs b/src/document/changes.rs
index 0409c50..19d4db6 100644
--- a/src/document/changes.rs
+++ b/src/document/changes.rs
@@ -28,10 +28,13 @@ pub(crate) fn commit_times(doc: &Document, since: &[ChangeHash]) -> Vec<i64> {
 }
 
 /// Who wrote the changes after `since`: the authors their writers set (a node's ID,
-/// `replica::authored`), each once; and whether any change has none (a snapshot, or a
-/// change of a node that set none).
-pub(crate) fn authors_since(doc: &Document, since: &[ChangeHash]) -> (Vec<String>, bool) {
-    let mut authors: Vec<String> = Vec::new();
+/// `replica::authored`), each once, with the hashes of their changes; and whether any
+/// change has none (a snapshot, or a change of a node that set none).
+pub(crate) fn authors_since(
+    doc: &Document,
+    since: &[ChangeHash],
+) -> (Vec<(String, Vec<ChangeHash>)>, bool) {
+    let mut authors: Vec<(String, Vec<ChangeHash>)> = Vec::new();
     let mut unknown = false;
     for change in doc.get_changes_meta(since) {
         match change
@@ -39,10 +42,10 @@ pub(crate) fn authors_since(doc: &Document, since: &[ChangeHash]) -> (Vec<String
             .as_ref()
             .and_then(|author| std::str::from_utf8(author.as_bytes()).ok())
         {
-            Some(author) if !authors.iter().any(|known| known == author) => {
-                authors.push(author.to_owned());
-            }
-            Some(_) => {}
+            Some(author) => match authors.iter_mut().find(|(known, _)| known == author) {
+                Some((_, hashes)) => hashes.push(change.hash),
+                None => authors.push((author.to_owned(), vec![change.hash])),
+            },
             None => unknown = true,
         }
     }
@@ -221,7 +224,11 @@ mod tests {
         merged.merge(&mut b).unwrap();
         let (mut authors, unknown) = authors_since(&merged, &since);
         authors.sort();
-        assert_eq!(authors, ["node-a", "node-b"]);
+        let counts: Vec<(&str, usize)> = authors
+            .iter()
+            .map(|(author, hashes)| (author.as_str(), hashes.len()))
+            .collect();
+        assert_eq!(counts, [("node-a", 2), ("node-b", 1)]);
         assert!(!unknown);
 
         // A change no node authored (a snapshot's, say).