Issue #3291949 by alexpott, daffie: Improve the MySQL transaction isolation warning

(cherry picked from commit 90f0da7b)

core/modules/mysql/mysql.install

@@ -28,16 +28,14 @@ function mysql_requirements($phase) {
 
       $isolation_level = $connection->query($query)->fetchField();
 
-      if ($isolation_level !== 'READ-COMMITTED') {
-        $requirements['mysql_transaction_level'] = [
-          'title' => t('Database Isolation Level'),
-          'severity' => REQUIREMENT_WARNING,
-          'value' => t('Transaction Isolation Level: @value', ['@value' => $isolation_level]),
-          'description' => t('For the best performance and to minimize locking issues, the READ-COMMITTED transaction isolation level is <a href=":performance_doc">recommended</a>.', [
-            ':performance_doc' => 'https://www.drupal.org/docs/system-requirements/setting-the-mysql-transaction-isolation-level',
-          ]),
-        ];
-      }
+      $requirements['mysql_transaction_level'] = [
+        'title' => t('Database Isolation Level'),
+        'severity' => $isolation_level === 'READ-COMMITTED' ? REQUIREMENT_OK : REQUIREMENT_WARNING,
+        'value' => $isolation_level,
+        'description' => t('For the best performance and to minimize locking issues, the READ-COMMITTED transaction isolation level is recommended. See the <a href=":performance_doc">setting MySQL transaction isolation level</a> page for more information.', [
+          ':performance_doc' => 'https://www.drupal.org/docs/system-requirements/setting-the-mysql-transaction-isolation-level',
+        ]),
+      ];
     }
   }
 

core/modules/mysql/tests/src/Functional/RequirementsTest.php

@@ -45,28 +45,31 @@ public function testIsolationLevelWarningNotDisplaying() {
     ]);
     $this->drupalLogin($admin_user);
 
-    // Change the isolation level to force the warning message.
+    // Set the isolation level to a level that produces a warning.
     $this->writeIsolationLevelSettings('REPEATABLE READ');
 
-    // Check if the warning message is being displayed.
+    // Check the message is not a warning.
     $this->drupalGet('admin/reports/status');
     $elements = $this->xpath('//details[@class="system-status-report__entry"]//div[contains(text(), :text)]', [
       ':text' => 'For the best performance and to minimize locking issues, the READ-COMMITTED',
     ]);
     $this->assertCount(1, $elements);
-    $this->assertStringStartsWith('Transaction Isolation Level', $elements[0]->getParent()->getText());
+    $this->assertStringStartsWith('REPEATABLE-READ', $elements[0]->getParent()->getText());
+    // Ensure it is a warning.
+    $this->assertStringContainsString('warning', $elements[0]->getParent()->getParent()->find('css', 'summary')->getAttribute('class'));
 
     // Rollback the isolation level to read committed.
     $this->writeIsolationLevelSettings('READ COMMITTED');
 
-    // Check if the warning message is gone.
+    // Check the message is not a warning.
     $this->drupalGet('admin/reports/status');
-    $this->assertSession()->pageTextNotContains('Database Isolation Level');
     $elements = $this->xpath('//details[@class="system-status-report__entry"]//div[contains(text(), :text)]', [
       ':text' => 'For the best performance and to minimize locking issues, the READ-COMMITTED',
     ]);
-
-    $this->assertCount(0, $elements);
+    $this->assertCount(1, $elements);
+    $this->assertStringStartsWith('READ-COMMITTED', $elements[0]->getParent()->getText());
+    // Ensure it is a not a warning.
+    $this->assertStringNotContainsString('warning', $elements[0]->getParent()->getParent()->find('css', 'summary')->getAttribute('class'));
   }
 
   /**