symfony
diff --git a/‎src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
+3-1Lines changed: 3 additions & 1 deletion b/‎src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
+3-1Lines changed: 3 additions & 1 deletion
diff --git a/‎src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php
+1Lines changed: 1 addition & 0 deletions b/‎src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php
+1Lines changed: 1 addition & 0 deletions
@@ -352,7 +352,9 @@ protected function validate(Request $request, Response $entry, $catch = false)
         }
 
         // add our cached last-modified validator
-        $subRequest->headers->set('if_modified_since', $entry->headers->get('Last-Modified'));
+        if ($entry->headers->has('Last-Modified')) {
+            $subRequest->headers->set('if_modified_since', $entry->headers->get('Last-Modified'));
+        }
 
         // Add our cached etag validator to the environment.
         // We keep the etags from the client to handle the case when the client
 
@@ -859,6 +859,7 @@ public function testValidatesCachedResponsesUseSameHttpMethod()
     public function testValidatesCachedResponsesWithETagAndNoFreshnessInformation()
     {
         $this->setNextResponse(200, [], 'Hello World', function ($request, $response) {
+            $this->assertFalse($request->headers->has('If-Modified-Since'));
             $response->headers->set('Cache-Control', 'public');
             $response->headers->set('ETag', '"12345"');
             if ($response->getETag() == $request->headers->get('IF_NONE_MATCH')) {
Original file line number	Diff line number	Diff line change
`@@ -859,6 +859,7 @@ public function testValidatesCachedResponsesUseSameHttpMethod()`
`859`	`859`	`public function testValidatesCachedResponsesWithETagAndNoFreshnessInformation()`
`860`	`860`	`{`
`861`	`861`	`$this->setNextResponse(200, [], 'Hello World', function ($request, $response) {`
	`862`	`+ $this->assertFalse($request->headers->has('If-Modified-Since'));`
`862`	`863`	`$response->headers->set('Cache-Control', 'public');`
`863`	`864`	`$response->headers->set('ETag', '"12345"');`
`864`	`865`	`if ($response->getETag() == $request->headers->get('IF_NONE_MATCH')) {`