fix(collab): build no repair for a batch refused for lack of permission (#1980)

crates/collab/src/server.rs

@@ -413,10 +413,14 @@ impl Server {
             // client learned what happened to it from the catch-up.
             ClientMsg::Changes { batch_id, .. } if self.issued.get(&from).is_some_and(|p| batch_id <= p.last_batch) => Vec::new(),
             ClientMsg::Changes { base_seq, batch_id, changes } => {
+                let mut denied = true;
                 let result = match self.limited.get(&from) {
                     Some(Access::View) => Err(Error::Invalid(VIEW_ONLY.into())),
                     Some(Access::Comment) if !changes.iter().all(Change::is_comment) => Err(Error::Invalid(COMMENT_ONLY.into())),
-                    _ => self.accept(from, base_seq, &changes),
+                    _ => {
+                        denied = false;
+                        self.accept(from, base_seq, &changes)
+                    }
                 };
                 if let Some(p) = self.issued.get_mut(&from) {
                     p.note(batch_id, result.is_err());
@@ -430,7 +434,9 @@ impl Server {
                     }
                     Err(e) => {
                         self.note(Journal::Refused { client: from, batch_id });
-                        let fixes = self.fixes(&changes).unwrap_or_default();
+                        // A refusal for lack of permission costs no repair: the client's confirmed copy
+                        // already is the server's state, so the fixes would only repeat it.
+                        let fixes = if denied { Vec::new() } else { self.fixes(&changes).unwrap_or_default() };
                         vec![Outgoing::To(from, ServerMsg::Reject { batch_id, reason: reason(&e), fixes })]
                     }
                 }

crates/collab/src/server_tests.rs

@@ -182,6 +182,26 @@ fn deleted_nodes_can_come_back_but_ids_are_never_handed_out_twice() {
     assert_eq!(s.document(), gone.document());
 }
 
+#[test]
+fn a_viewers_refused_deletion_gets_no_repair() {
+    let (d, _, frame) = doc();
+    let mut s = Server::new(d, "tok", Limits::default());
+    let (id, out) = s.join_as(hello("tok"), crate::message::Access::View).unwrap();
+    let Some(Outgoing::To(_, welcome)) = out.into_iter().next() else { panic!() };
+    let mut v = Client::join(welcome).unwrap();
+    let del = edit(&mut v, |d| d.remove(frame).unwrap());
+    let (reason, fixes) = rejected(
+        &mut s,
+        id,
+        match del {
+            ClientMsg::Changes { changes, .. } => changes,
+            _ => panic!(),
+        },
+    );
+    assert_eq!(reason, crate::VIEW_ONLY);
+    assert!(fixes.is_empty(), "{fixes:?}");
+}
+
 #[test]
 fn fixes_roll_a_rejected_client_back_to_the_server_state() {
     let (d, _, frame) = doc();