From 67620024a2d27280cdd977ea0e2d2673f8b7395b Mon Sep 17 00:00:00 2001
From: Ephraim Duncan <55143799+ephraimduncan@users.noreply.github.com>
Date: Thu, 10 Sep 2026 10:33:59 +0000
Subject: [PATCH] fix(header-analysis): report the last cache-status member
 (#2681)

---
 .../src/cdn/normalize-cache-status.test.ts    | 19 +++++++++++++++++++
 .../src/cdn/normalize-cache-status.ts         |  6 ++++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/packages/header-analysis/src/cdn/normalize-cache-status.test.ts b/packages/header-analysis/src/cdn/normalize-cache-status.test.ts
index 1e736d9e..f6f3743c 100644
--- a/packages/header-analysis/src/cdn/normalize-cache-status.test.ts
+++ b/packages/header-analysis/src/cdn/normalize-cache-status.test.ts
@@ -47,6 +47,7 @@ describe("cloudfront / fastly / akamai (x-cache)", () => {
     ["RefreshHit from cloudfront", "EXPIRED"],
     ["HIT", "HIT"],
     ["MISS, HIT", "HIT"],
+    ["HIT, MISS", "HIT"],
     [
       "TCP_HIT from a23-45-67-89.deploy.akamaitechnologies.com (AkamaiGHost)",
       "HIT",
@@ -70,13 +71,31 @@ describe("rfc 9211 cache-status", () => {
     ["ExampleCache; fwd=miss; stored", "MISS"],
     ["ExampleCache; fwd=stale", "EXPIRED"],
     ["ExampleCache; fwd=bypass", "BYPASS"],
+    ["OriginCache; hit, EdgeCache; fwd=miss", "MISS"],
+    ["OriginCache; fwd=miss, EdgeCache; hit", "HIT"],
+    ["OriginCache; fwd=bypass, EdgeCache; fwd=stale", "EXPIRED"],
+    ['OriginCache; hit, "Edge, Cache"; fwd=miss', "MISS"],
+    ['OriginCache; hit, EdgeCache; fwd=miss; detail="a,b; hit"', "MISS"],
+    [
+      String.raw`OriginCache; hit, EdgeCache; fwd=miss; detail="a\",b; hit"`,
+      "MISS",
+    ],
+    [String.raw`OriginCache; detail="a\\"; hit, EdgeCache; fwd=miss`, "MISS"],
   ] as const) {
     test(`cache-status: ${raw} -> ${status}`, () => {
       const result = normalizeCacheStatus({ "Cache-Status": raw });
       expect(result.status).toBe(status);
       expect(result.source).toBe("cache-status");
+      expect(result.raw).toBe(raw);
     });
   }
+
+  test("does not use an upstream hit when the last cache has no status", () => {
+    expect(
+      normalizeCacheStatus({ "Cache-Status": "OriginCache; hit, EdgeCache" })
+        .status,
+    ).toBe("UNKNOWN");
+  });
 });
 
 describe("vendor header priority", () => {
diff --git a/packages/header-analysis/src/cdn/normalize-cache-status.ts b/packages/header-analysis/src/cdn/normalize-cache-status.ts
index 54a5c923..cc89cfaf 100644
--- a/packages/header-analysis/src/cdn/normalize-cache-status.ts
+++ b/packages/header-analysis/src/cdn/normalize-cache-status.ts
@@ -38,9 +38,11 @@ function fromToken(value: string): CacheStatus | null {
   return null;
 }
 
-// RFC 9211, e.g. `"Netlify Edge"; hit` or `ExampleCache; fwd=miss; stored`
+// RFC 9211 lists the cache closest to the user last.
 function fromCacheStatusHeader(value: string): CacheStatus | null {
-  const lower = value.toLowerCase();
+  // Quoted strings can contain commas and text that resembles parameters.
+  const unquoted = value.replace(/"(?:[^"\\]|\\.)*"/g, '""');
+  const lower = unquoted.slice(unquoted.lastIndexOf(",") + 1).toLowerCase();
   if (/;\s*hit/.test(lower)) return "HIT";
   const fwd = lower.match(/fwd=([a-z-]+)/)?.[1];
   if (!fwd) return null;
-- 
2.51.2