From 00e8108714a4395fb3fde0703ccda90a9d8d434a Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Wed, 27 May 2026 16:59:21 +0100
Subject: [PATCH] Handle the case of a very large duration

---
 rust/src/duration.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/rust/src/duration.rs b/rust/src/duration.rs
index 9fb0048fd8..72a1027875 100644
--- a/rust/src/duration.rs
+++ b/rust/src/duration.rs
@@ -38,7 +38,10 @@ impl SynapseDuration {
     /// For now we only need to create durations from milliseconds.
     pub const fn from_milliseconds(milliseconds: u64) -> Self {
         Self {
-            microseconds: milliseconds * 1_000,
+            // We saturate at u64::MAX microseconds to avoid overflow, which
+            // means that the maximum duration we can represent is approximately
+            // 584,942 years.
+            microseconds: milliseconds.saturating_mul(1_000),
         }
     }
 }