fix: don't set permanent caching header when res.revalidate() was used (#2810)

* test: api route calling res.revalidate on path returning notFound: true is not cacheable * fix: don't set permanent caching header when res.revalidate() was used * test: adjust added test name, add some context, handle case of header not being set --------- Co-authored-by: Mateusz Bocian <mrstork@users.noreply.github.com>

Author: pieh

src/run/headers.ts

@@ -266,7 +266,8 @@ export const setCacheControlHeaders = (
  ['GET', 'HEAD'].includes(request.method) &&
  !headers.has('cdn-cache-control') &&
  !headers.has('netlify-cdn-cache-control') &&
- requestContext.usedFsReadForNonFallback
+ requestContext.usedFsReadForNonFallback &&
+ !requestContext.didPagesRouterOnDemandRevalidate
  ) {
  // handle CDN Cache Control on static files
  headers.set('cache-control', 'public, max-age=0, must-revalidate')

tests/e2e/page-router.test.ts

@@ -590,6 +590,21 @@ test.describe('Simple Page Router (no basePath, no i18n)', () => {
  'getStaticProps duration should not be longer than 10 seconds',
  ).toBeLessThan(10_000)
  })
+
+ test('API route calling res.revalidate() on page returning notFound: true is not cacheable', async ({
+ page,
+ pageRouter,
+ }) => {
+ // note: known conditions for problematic case is
+ // 1. API route needs to call res.revalidate()
+ // 2. revalidated page's getStaticProps must return notFound: true
+ const response = await page.goto(
+ new URL('/api/revalidate?path=/static/not-found', pageRouter.url).href,
+ )
+
+ expect(response?.status()).toEqual(200)
+ expect(response?.headers()['netlify-cdn-cache-control'] ?? '').not.toMatch(/(s-maxage|max-age)/)
+ })
 })
 
 test.describe('Page Router with basePath and i18n', () => {