From 73b6648d06a181b52b597e6968217b5011462197 Mon Sep 17 00:00:00 2001
From: "Dustin J. Mitchell" <dustin@mozilla.com>
Date: Fri, 7 May 2021 22:40:48 +0000
Subject: [PATCH] assert that working-set element 0 is None

---
 taskchampion/src/workingset.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/taskchampion/src/workingset.rs b/taskchampion/src/workingset.rs
index 586a16cf4..04aa4dcc5 100644
--- a/taskchampion/src/workingset.rs
+++ b/taskchampion/src/workingset.rs
@@ -21,6 +21,10 @@ impl WorkingSet {
     /// Create a new WorkingSet.  Typically this is acquired via `replica.working_set()`
     pub(crate) fn new(by_index: Vec<Option<Uuid>>) -> Self {
         let mut by_uuid = HashMap::new();
+
+        // working sets are 1-indexed, so element 0 should always be None
+        assert!(by_index.is_empty() || by_index[0].is_none());
+
         for (index, uuid) in by_index.iter().enumerate() {
             if let Some(uuid) = uuid {
                 by_uuid.insert(*uuid, index);