Issue #2352207 by martin107, Berdir: Database cache backend does not treat cid as case sensitive

core/lib/Drupal/Core/Cache/CacheBackendInterface.php

@@ -14,6 +14,8 @@ namespace Drupal\Core\Cache;
  * Drupal\Core\Cache\DatabaseBackend provides the default implementation, which
  * can be consulted as an example.
  *
+ * The cache indentifiers are case sensitive.
+ *
  * @ingroup cache
  */
 interface CacheBackendInterface {

core/lib/Drupal/Core/Cache/DatabaseBackend.php

@@ -564,6 +564,7 @@ class DatabaseBackend implements CacheBackendInterface {
           'length' => 255,
           'not null' => TRUE,
           'default' => '',
+          'binary' => TRUE,
         ),
         'data' => array(
           'description' => 'A collection of data to cache.',

core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php

@@ -213,6 +213,11 @@ abstract class GenericCacheBackendUnitTestBase extends DrupalUnitTestBase {
     $backend->set($cid, 'test');
     $this->assertEqual('test', $backend->get($cid)->data);
 
+    // Check that the cache key is case sensitive.
+    $backend->set('TEST8', 'value');
+    $this->assertEqual('value', $backend->get('TEST8')->data);
+    $this->assertFalse($backend->get('test8'));
+
     // Calling ::set() with invalid cache tags.
     try {
       $backend->set('exception_test', 'value', Cache::PERMANENT, ['node' => [3, 5, 7]]);