fix(server): a refused batch counts toward a log's size, not toward a snapshot rewrite

apps/figcraft-server/src/store/backend.rs

@@ -68,7 +68,9 @@ impl Backend for Store {
                 Err(err) => log::error!("file {file}: a change couldn't be logged: {err}"),
             }
         }
-        log.entries += journal.len();
+        // A refusal changes nothing in the document: it counts toward the log's size (bytes), but
+        // not toward the entries that make a snapshot rewrite worthwhile.
+        log.entries += journal.iter().filter(|j| !matches!(j, figcraft_collab::Journal::Refused { .. })).count();
         log.dirty = true;
         e.meta.updated = now();
         if log.entries >= after || log.bytes + log.pending.len() as u64 >= max_bytes {

apps/figcraft-server/src/store_tests.rs

@@ -155,6 +155,24 @@ fn read_only_sessions_keep_client_ids_without_rewriting_the_snapshot() {
     }
 }
 
+#[test]
+fn a_viewers_refused_batches_do_not_rewrite_the_snapshot() {
+    let dir = TempDir::new("refusals");
+    let c = StoreConfig { compact_after: 3, ..cfg(dir.path()) };
+    let mut store = Store::open(dir.path(), c).unwrap();
+    let (id, _, _) = publish(&mut store, "Busy");
+    let mut server = store.open(&id).unwrap();
+    let mut v = join(&mut server, Access::View);
+    store.changed(&id, &mut server);
+    let generation = || disk::check_snapshot(&fs::read(dir.path().join(FILES).join(&id).join(SNAPSHOT)).unwrap()).unwrap();
+    assert_eq!(generation(), 1);
+    for i in 0..10 {
+        rename(&mut server, &mut v, &format!("P{i}"));
+        store.changed(&id, &mut server);
+    }
+    assert_eq!(generation(), 1, "refusals are logged, not compacted");
+}
+
 #[test]
 fn a_long_log_is_compacted_while_open() {
     let dir = TempDir::new("compact");