Issue #3192487 by andypost, murilohp, Gábor Hojtsy, daffie, pobster, apaderno: Warn about upcoming JSON database support requirement in Drupal 9

(cherry picked from commit 206d6ee658)

core/lib/Drupal/Core/Database/Connection.php

@@ -2185,4 +2185,19 @@ abstract class Connection {
     return \Drupal::service('pager.manager');
   }
 
+  /**
+   * Runs a simple query to validate json datatype support.
+   *
+   * @return bool
+   *   Returns the query result.
+   */
+  public function hasJson(): bool {
+    try {
+      return (bool) $this->query('SELECT JSON_TYPE(\'1\')');
+    }
+    catch (\Exception $e) {
+      return FALSE;
+    }
+  }
+
 }

core/modules/pgsql/src/Driver/Database/pgsql/Connection.php

@@ -368,6 +368,18 @@ class Connection extends DatabaseConnection {
     }
   }
 
+  /**
+   * {@inheritDoc}
+   */
+  public function hasJson(): bool {
+    try {
+      return (bool) $this->query('SELECT JSON_TYPEOF(\'1\')');
+    }
+    catch (\Exception $e) {
+      return FALSE;
+    }
+  }
+
 }
 
 /**

core/modules/system/system.install

@@ -487,6 +487,22 @@ function system_requirements($phase) {
     }
   }
 
+  if ($phase == 'runtime') {
+    // Test JSON support. To be required from Drupal 10.0.
+    // @todo remove in https://www.drupal.org/project/drupal/issues/3203193
+    $requirements['database_support_json'] = [
+      'title' => t('Database support for JSON'),
+      'severity' => REQUIREMENT_OK,
+      'value' => t('Available'),
+      'description' => t('Is required in Drupal 10.0.'),
+    ];
+
+    if (!Database::getConnection()->hasJson()) {
+      $requirements['database_support_json']['value'] = t('Not available');
+      $requirements['database_support_json']['severity'] = REQUIREMENT_WARNING;
+    }
+  }
+
   // Test PHP memory_limit
   $memory_limit = ini_get('memory_limit');
   $requirements['php_memory_limit'] = [

core/modules/system/tests/src/Functional/System/StatusTest.php

@@ -91,6 +91,14 @@ class StatusTest extends BrowserTestBase {
     $this->drupalGet('admin/reports/status');
     $this->assertSession()->elementExists('xpath', '//details[contains(@class, "system-status-report__entry")]//div[contains(text(), "Cron has not run recently")]');
     \Drupal::state()->set('system.cron_last', $cron_last_run);
+
+    // Check if JSON database support is enabled.
+    $this->assertSession()->pageTextContains('Database support for JSON');
+    $elements = $this->xpath('//details[@class="system-status-report__entry"]//div[contains(text(), :text)]', [
+      ':text' => 'Is required in Drupal 10.0.',
+    ]);
+    $this->assertCount(1, $elements);
+    $this->assertStringStartsWith('Available', $elements[0]->getParent()->getText());
   }
 
 }