[HttpKernel] [HttpCache] Keep s-maxage=0 from ESI sub-responses

Author: mpdude

HttpCache/ResponseCacheStrategy.php

@@ -81,8 +81,10 @@ public function add(Response $response)
             return;
         }
 
-        $this->storeRelativeAgeDirective('max-age', $response->headers->getCacheControlDirective('max-age'), $age);
-        $this->storeRelativeAgeDirective('s-maxage', $response->headers->getCacheControlDirective('s-maxage') ?: $response->headers->getCacheControlDirective('max-age'), $age);
+        $maxAge = $response->headers->hasCacheControlDirective('max-age') ? (int) $response->headers->getCacheControlDirective('max-age') : null;
+        $this->storeRelativeAgeDirective('max-age', $maxAge, $age);
+        $sharedMaxAge = $response->headers->hasCacheControlDirective('s-maxage') ? (int) $response->headers->getCacheControlDirective('s-maxage') : $maxAge;
+        $this->storeRelativeAgeDirective('s-maxage', $sharedMaxAge, $age);
 
         $expires = $response->getExpires();
         $expires = null !== $expires ? (int) $expires->format('U') - (int) $response->getDate()->format('U') : null;

Tests/HttpCache/ResponseCacheStrategyTest.php

@@ -377,6 +377,22 @@ public function cacheControlMergingProvider()
             ],
         ];
 
+        yield 's-maxage may be set to 0' => [
+            ['public' => true, 's-maxage' => '0', 'max-age' => null],
+            ['public' => true, 's-maxage' => '0'],
+            [
+                ['public' => true, 's-maxage' => '60'],
+            ],
+        ];
+
+        yield 's-maxage may be set to 0, and works independently from maxage' => [
+            ['public' => true, 's-maxage' => '0', 'max-age' => '30'],
+            ['public' => true, 's-maxage' => '0', 'max-age' => '30'],
+            [
+                ['public' => true, 'max-age' => '60'],
+            ],
+        ];
+
         yield 'result is private when combining private responses' => [
             ['no-cache' => false, 'must-revalidate' => false, 'private' => true],
             ['s-maxage' => 60, 'private' => true],