From 8d4a43b2c259b81361d3d3aca16ea3b61b59283b Mon Sep 17 00:00:00 2001
From: John Lambert <john_lambert@sil.org>
Date: Fri, 11 Oct 2024 10:20:01 -0400
Subject: [PATCH] If there are no enumerators, it enters an infinite loop.

---
 src/SIL.Machine/Utils/EnumerableExtensions.cs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/SIL.Machine/Utils/EnumerableExtensions.cs b/src/SIL.Machine/Utils/EnumerableExtensions.cs
index 1c2fc72b0..8bab692e2 100644
--- a/src/SIL.Machine/Utils/EnumerableExtensions.cs
+++ b/src/SIL.Machine/Utils/EnumerableExtensions.cs
@@ -13,6 +13,8 @@ Func<IEnumerable<TSource>, TResult> selector
         {
             // ToList is necessary to avoid deferred execution
             List<IEnumerator<TSource>> enumerators = source.Select(seq => seq.GetEnumerator()).ToList();
+            if (enumerators.Count == 0)
+                yield break;
             try
             {
                 while (true)