MC-35778: Integration failures on Magento 2.3-develop with MariaDB 10.2

Author: fascinosum

lib/internal/Magento/Framework/Setup/Declaration/Schema/Db/DefinitionAggregator.php

@@ -6,8 +6,7 @@
 
 namespace Magento\Framework\Setup\Declaration\Schema\Db;
 
-use Magento\Framework\DB\Adapter\ConnectionException;
-use Magento\Framework\DB\Adapter\SqlVersionProvider;
+use Magento\Framework\App\ResourceConnection;
 use Magento\Framework\Setup\Declaration\Schema\Dto\ElementInterface;
 
 /**
@@ -21,20 +20,25 @@ class DefinitionAggregator implements DbDefinitionProcessorInterface
     private $definitionProcessors;
 
     /**
-     * @var SqlVersionProvider
+     * @var ResourceConnection
      */
-    private $sqlVersionProvider;
+    private $resourceConnection;
 
     /**
-     * @param SqlVersionProvider $sqlVersionProvider
+     * @var string
+     */
+    private $dbVersion;
+
+    /**
+     * @param ResourceConnection $resourceConnection
      * @param DbDefinitionProcessorInterface[] $definitionProcessors
      */
     public function __construct(
-        SqlVersionProvider $sqlVersionProvider,
+        ResourceConnection $resourceConnection,
         array $definitionProcessors
     ) {
         $this->definitionProcessors = $definitionProcessors;
-        $this->sqlVersionProvider = $sqlVersionProvider;
+        $this->resourceConnection = $resourceConnection;
     }
 
     /**
@@ -73,6 +77,21 @@ public function fromDefinition(array $data)
         return $definitionProcessor->fromDefinition($data);
     }
 
+    /**
+     * Get DB version
+     *
+     * @return string
+     */
+    private function getDatabaseVersion(): string
+    {
+        if (!$this->dbVersion) {
+            $this->dbVersion = $this->resourceConnection->getConnection('default')
+                ->fetchPairs("SHOW variables LIKE 'version'")['version'];
+        }
+
+        return $this->dbVersion;
+    }
+
     /**
      * Processes `$value` to be compatible with MySQL.
      *
@@ -88,7 +107,7 @@ protected function processDefaultValue(array $data)
         if ($defaultValue === "'NULL'") {
             return "NULL";
         }
-        if ($defaultValue === "NULL" && $this->isMariaDbSqlConnection()) {
+        if ($defaultValue === "NULL" && strpos($this->getDatabaseVersion(), 'MariaDB') !== false) {
             return null;
         }
         /*
@@ -108,18 +127,4 @@ protected function processDefaultValue(array $data)
 
         return $defaultValue;
     }
-
-    /**
-     * Checks if MariaDB used as SQL engine
-     *
-     * @return bool
-     * @throws ConnectionException
-     */
-    private function isMariaDbSqlConnection(): bool
-    {
-        return strpos(
-            $this->sqlVersionProvider->getSqlVersion(),
-            SqlVersionProvider::MARIA_DB_10_VERSION
-        ) === 0;
-    }
 }