From 8b6b91011ff7bec27f5a4298ac9868a522661cdd Mon Sep 17 00:00:00 2001
From: Tristan Swadell <tswadell@google.com>
Date: Fri, 3 Jul 2026 15:59:51 +0100
Subject: [PATCH] Update lists.go runtime cost calculator

Ensure negative cost factors are normalized to 1.0 to safeguard against error inputs.
---
 ext/lists.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/ext/lists.go b/ext/lists.go
index 37ae2d3d..b4ac2589 100644
--- a/ext/lists.go
+++ b/ext/lists.go
@@ -779,6 +779,9 @@ func trackListSelfCompare(l traits.Lister) *uint64 {
 // trackAllocatingListCall computes costs as a function of the size of the result list with a baseline cost
 // for the call dispatch and the associated list allocation.
 func trackAllocatingListCall(costFactor float64, size uint64) *uint64 {
+	if costFactor < 0.0 {
+		costFactor = 1.0
+	}
 	cost := safeAdd(uint64(float64(size)*costFactor), callCost, common.ListCreateBaseCost)
 	return &cost
 }