From 2f6f181d1acc292de0bea863db7ec9d3fc86f2ef Mon Sep 17 00:00:00 2001
From: Ruihang Xia <waynestxia@gmail.com>
Date: Sat, 28 Mar 2026 11:42:31 +0800
Subject: [PATCH] fix gauge rate case

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>
---
 src/promql/src/functions/extrapolate_rate.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/promql/src/functions/extrapolate_rate.rs b/src/promql/src/functions/extrapolate_rate.rs
index cc70448d20..a084fe480f 100644
--- a/src/promql/src/functions/extrapolate_rate.rs
+++ b/src/promql/src/functions/extrapolate_rate.rs
@@ -69,7 +69,9 @@ impl<const IS_COUNTER: bool, const IS_RATE: bool> ExtrapolatedRate<IS_COUNTER, I
             (true, true) => "prom_rate",
             (true, false) => "prom_increase",
             (false, false) => "prom_delta",
-            (false, true) => "prom_delta",
+            (false, true) => {
+                unreachable!("gauge rate is not supported by ExtrapolatedRate")
+            }
         }
     }