core/lib/Drupal/Core/Cache/Context/QueryArgsCacheContext.php | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/core/lib/Drupal/Core/Cache/Context/QueryArgsCacheContext.php b/core/lib/Drupal/Core/Cache/Context/QueryArgsCacheContext.php
index 9b4eb0d..0926ba6 100644
--- a/core/lib/Drupal/Core/Cache/Context/QueryArgsCacheContext.php
+++ b/core/lib/Drupal/Core/Cache/Context/QueryArgsCacheContext.php
@@ -28,7 +28,13 @@ public function getContext($query_arg = NULL) {
       return $this->requestStack->getCurrentRequest()->getQueryString();
     }
     elseif ($this->requestStack->getCurrentRequest()->query->has($query_arg)) {
-      return $this->requestStack->getCurrentRequest()->query->get($query_arg) ?: '?valueless?';
+      $value = $this->requestStack->getCurrentRequest()->query->get($query_arg);
+      if ($value !== '') {
+        return $value;
+      }
+      else {
+        return '?valueless?';
+      }
     }
     else {
       return NULL;