diff --git a/crates/sidebar/src/sidebar.rs b/crates/sidebar/src/sidebar.rs
index c1db65927f0319881ae15b4e581fc1912ee814df..881549bcffcd18924037a92b4427a54e64ce079f 100644
--- a/crates/sidebar/src/sidebar.rs
+++ b/crates/sidebar/src/sidebar.rs
@@ -812,6 +812,10 @@ impl Sidebar {
                 }
             }
         }
+        debug_assert!(
+            pending.is_empty(),
+            "all workspaces should be absorbed by a parent"
+        );
 
         // Build a mapping from worktree checkout paths → root repo paths so
         // that threads saved against a worktree checkout can be grouped under