huskies: merge 874

server/src/crdt_state/read.rs

@@ -249,8 +249,13 @@ pub fn evict_item(story_id: &str) -> Result<(), String> {
 
     // Resolve the item's OpId before the closure (the closure will mutably
     // borrow `state`, so we can't access `state.crdt.doc.items` from inside).
+    //
+    // `rebuild_index` uses `items.iter()` which skips the invisible ROOT
+    // sentinel, so `idx` is a 0-based visible-item position.  `id_at` counts
+    // ALL non-deleted ops including the sentinel at position 0, so we must
+    // add 1 to translate from visible-item position to `id_at` position.
     let item_id =
-        state.crdt.doc.items.id_at(idx).ok_or_else(|| {
+        state.crdt.doc.items.id_at(idx + 1).ok_or_else(|| {
             format!("Item index {idx} for '{story_id}' did not resolve to an OpId")
         })?;