From 237e8b8bb205042d89b6826f545b86ba9bc02b0a Mon Sep 17 00:00:00 2001
From: Mike Dilger <mike@mikedilger.com>
Date: Thu, 23 Feb 2023 17:43:36 +1300
Subject: [PATCH] Handle no relays condition without panicking

---
 src/relays.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/relays.rs b/src/relays.rs
index f5930262..ff854cbc 100644
--- a/src/relays.rs
+++ b/src/relays.rs
@@ -30,6 +30,9 @@ impl RelayAssignment {
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[allow(clippy::enum_variant_names)]
 pub enum RelayPickFailure {
+    /// No relays to pick from
+    NoRelays,
+
     /// No people left to assign. A good result.
     NoPeopleLeft,
 
@@ -40,6 +43,7 @@ pub enum RelayPickFailure {
 impl fmt::Display for RelayPickFailure {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
+            RelayPickFailure::NoRelays => write!(f, "No relays to pick from."),
             RelayPickFailure::NoPeopleLeft => write!(f, "All people accounted for."),
             RelayPickFailure::NoProgress => write!(f, "Unable to make further progress."),
         }
@@ -199,6 +203,10 @@ impl RelayTracker {
             return Err(RelayPickFailure::NoPeopleLeft);
         }
 
+        if self.all_relays.is_empty() {
+            return Err(RelayPickFailure::NoRelays);
+        }
+
         // Keep score for each relay
         let scoreboard: DashMap<RelayUrl, u64> = self
             .all_relays