fix: fix cache analysis not rendering when edge cache miss occurs

app/utils/getCacheAnalysis.test.ts

@@ -66,6 +66,39 @@ describe('getCacheAnalysis', () => {
 
     expect(() => getCacheAnalysis(headers, now)).toThrow('Could not determine who served the request')
   })
+
+  it('handles cache miss without function headers (issue reproduction)', () => {
+    // This reproduces the exact headers from the issue where no cache analysis is rendered
+    const headers = {
+      'age': '0',
+      'cache-control': 'public,max-age=0,must-revalidate',
+      'cache-status': '"Netlify Edge"; fwd=miss',
+      'content-encoding': 'br',
+      'content-type': 'text/html; charset=UTF-8',
+      'date': 'Sat, 05 Jul 2025 00:18:32 GMT',
+      'debug-x-bb-deploy-id': '6866a5e3ddbff100081b7ff8',
+      'debug-x-bb-gen': '6866a5e3ddbff100081b7ff8:1751557850611',
+      'debug-x-bb-host-id': 'cdn-glo-aws-cmh-57, cdn-glo-aws-cmh-57',
+      'debug-x-nf-cache-info': 'hit=0,fresh=0,swr=0,cacheable=1,mem=0,rww=0,ort=1,owt=1',
+      'debug-x-nf-cache-result': 'miss',
+      'etag': '"92de5e34923e8d6e08269210e3bae88d-ssl-df"',
+      'vary': 'Accept-Encoding',
+    }
+    const now = Date.now()
+
+    // This should now work correctly instead of throwing an error
+    const result = getCacheAnalysis(headers, now)
+
+    expect(result).toHaveProperty('servedBy')
+    expect(result).toHaveProperty('cacheStatus')
+    expect(result).toHaveProperty('cacheControl')
+    expect(result.servedBy.source).toBe(ServedBySource.CDN)
+    expect(result.servedBy.cdnNodes).toBe('cdn-glo-aws-cmh-57')
+    expect(result.cacheStatus).toHaveLength(1)
+    expect(result.cacheStatus[0]?.cacheName).toBe('Netlify Edge')
+    expect(result.cacheStatus[0]?.parameters.hit).toBe(false)
+    expect(result.cacheStatus[0]?.parameters.fwd).toBe('miss')
+  })
 })
 
 describe('parseCacheStatus', () => {

app/utils/getCacheAnalysis.ts

@@ -1,5 +1,7 @@
-import { getServedBy, type ServedBy } from './getServedBy'
-import { parseCacheControl, type ParsedCacheControl } from './parseCacheControl'
+import { getServedBy } from './getServedBy'
+import type { ServedBy } from './getServedBy'
+import { parseCacheControl } from './parseCacheControl'
+import type { ParsedCacheControl } from './parseCacheControl'
 
 const CACHE_NAMES_SORTED_BY_RFC_9211 = [
   'Next.js',

app/utils/getServedBy.test.ts

@@ -1,6 +1,7 @@
 import { describe, it, expect } from 'vitest'
 
-import { getServedBy, ServedBySource, type ParsedCacheStatusEntry } from './getServedBy'
+import { getServedBy, ServedBySource } from './getServedBy'
+import type { ParsedCacheStatusEntry } from './getServedBy'
 
 describe('getServedBy', () => {
   it('returns CDN when Netlify Edge cache has a hit', () => {
@@ -183,4 +184,26 @@ describe('getServedBy', () => {
 
     expect(result.source).toBe(ServedBySource.DurableCache)
   })
+
+  it('falls back to CDN when no cache hits and no function headers but CDN host is present', () => {
+    const headers = new Headers({
+      'Debug-X-BB-Host-Id': 'cdn-glo-aws-cmh-57, cdn-glo-aws-cmh-57',
+    })
+    const cacheStatus: ParsedCacheStatusEntry[] = [
+      {
+        cacheName: 'Netlify Edge',
+        parameters: {
+          hit: false,
+          fwd: 'miss',
+          stored: false,
+          collapsed: false,
+        },
+      },
+    ]
+
+    const result = getServedBy(headers, cacheStatus)
+
+    expect(result.source).toBe(ServedBySource.CDN)
+    expect(result.cdnNodes).toBe('cdn-glo-aws-cmh-57')
+  })
 })

app/utils/getServedBy.ts

@@ -58,6 +58,11 @@ const getServedBySource = (
   if (cacheHeaders.has('Debug-X-NF-Edge-Functions'))
     return ServedBySource.EdgeFunction
 
+  // If no cache hits and no function headers, but CDN was involved (indicated by Debug-X-BB-Host-Id),
+  // then the CDN served the request (likely a cache miss that was forwarded to origin)
+  if (cacheHeaders.has('Debug-X-BB-Host-Id'))
+    return ServedBySource.CDN
+
   throw new Error(
     `Could not determine who served the request. Cache status: ${cacheStatus}`,
   )