From 7b619fbbddcf73511730942e08fbe88db2c2c83d Mon Sep 17 00:00:00 2001
From: "Sharad." <sharadvc@users.noreply.github.com>
Date: Sat, 12 Sep 2026 14:30:48 +0000
Subject: [PATCH] fix: reject non-finite scorer weights in suite validation

Fixes #29

Co-authored-by: Sharad. <sharadvc@users.noreply.github.com>
---
 src/scorers/util.ts |  3 ++-
 src/suite.ts        |  4 ++--
 tests/suite.test.ts | 18 ++++++++++++++++++
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/src/scorers/util.ts b/src/scorers/util.ts
index 4a82776..6d9c4de 100644
--- a/src/scorers/util.ts
+++ b/src/scorers/util.ts
@@ -9,7 +9,8 @@ export function clamp01(n: number): number {
 /** Read the weight from a spec, defaulting to 1 and rejecting negatives. */
 export function specWeight(spec: ScorerSpec): number {
   const w = typeof spec.weight === "number" ? spec.weight : 1;
-  return w < 0 ? 0 : w;
+  if (!Number.isFinite(w) || w < 0) return 0;
+  return w;
 }
 
 /** Convenience builder that fills in the boilerplate of a {@link ScoreResult}. */
diff --git a/src/suite.ts b/src/suite.ts
index 214c139..1439e08 100644
--- a/src/suite.ts
+++ b/src/suite.ts
@@ -137,8 +137,8 @@ function validateScorer(data: unknown, caseId: string, index: number): ScorerSpe
   );
   if (s.weight !== undefined) {
     assert(
-      typeof s.weight === "number" && s.weight >= 0,
-      `case "${caseId}" scorers[${index}].weight must be a non-negative number`,
+      typeof s.weight === "number" && Number.isFinite(s.weight) && s.weight >= 0,
+      `case "${caseId}" scorers[${index}].weight must be a finite non-negative number`,
     );
   }
   return s as ScorerSpec;
diff --git a/tests/suite.test.ts b/tests/suite.test.ts
index 70dcc91..e9cba7a 100644
--- a/tests/suite.test.ts
+++ b/tests/suite.test.ts
@@ -72,6 +72,24 @@ cases:
     ).toThrow(/at least one scorer/);
   });
 
+  it.each([Number.POSITIVE_INFINITY, Number.NEGATIVE_INFINITY, Number.NaN])(
+    "rejects non-finite scorer weight (%s)",
+    (weight) => {
+      expect(() =>
+        validateSuite({
+          name: "d",
+          cases: [
+            {
+              id: "x",
+              input: { prompt: "a" },
+              scorers: [{ type: "regex", weight }],
+            },
+          ],
+        }),
+      ).toThrow(/scorers\[0\]\.weight/);
+    },
+  );
+
   it("rejects an out-of-range threshold", () => {
     expect(() =>
       validateSuite({