fix fullTableName duplicate prefix, closes #2355

lib/Cake/Model/Datasource/DboSource.php

@@ -920,7 +920,7 @@ class DboSource extends DataSource {
 		if (is_object($model)) {
 			$schemaName = $model->schemaName;
 			$table = $model->tablePrefix . $model->table;
-		} elseif (isset($this->config['prefix'])) {
+		} elseif (!empty($this->config['prefix']) && strpos($model, $this->config['prefix']) === false) {
 			$table = $this->config['prefix'] . strval($model);
 		} else {
 			$table = strval($model);

lib/Cake/Test/Case/Model/Datasource/Database/MysqlTest.php

@@ -3540,4 +3540,37 @@ class MysqlTest extends CakeTestCase {
 		$this->Dbo->delete($Article, true);
 		$this->Dbo->delete($Article, '2=2');
 	}
+
+/**
+ * Test truncate with a mock.
+ *
+ * @return void
+ */
+	public function testTruncateStatements() {
+		$this->loadFixtures('Article', 'User');
+		$db = ConnectionManager::getDatasource('test');
+		$schema = $db->config['database'];
+		$Article = new Article();
+
+		$this->Dbo = $this->getMock('Mysql', array('execute'), array($db->config));
+
+		$this->Dbo->expects($this->at(0))->method('execute')
+			->with("TRUNCATE TABLE `$schema`.`articles`");
+		$this->Dbo->truncate($Article);
+
+		$this->Dbo->expects($this->at(0))->method('execute')
+			->with("TRUNCATE TABLE `$schema`.`articles`");
+		$this->Dbo->truncate('articles');
+
+		// #2355: prevent duplicate prefix
+		$this->Dbo->config['prefix'] = 'tbl_';
+		$Article->tablePrefix = 'tbl_';
+		$this->Dbo->expects($this->at(0))->method('execute')
+			->with("TRUNCATE TABLE `$schema`.`tbl_articles`");
+		$this->Dbo->truncate($Article);
+
+		$this->Dbo->expects($this->at(0))->method('execute')
+			->with("TRUNCATE TABLE `$schema`.`tbl_articles`");
+		$this->Dbo->truncate('articles');
+	}
 }

lib/Cake/Test/Case/Model/Datasource/Database/PostgresTest.php

@@ -871,4 +871,38 @@ class PostgresTest extends CakeTestCase {
 		$result = $this->Dbo->getEncoding();
 		$this->assertEquals('EUC-JP', $result) ;
 	}
+
+/**
+ * Test truncate with a mock.
+ *
+ * @return void
+ */
+	public function testTruncateStatements() {
+		$this->loadFixtures('Article', 'User');
+		$db = ConnectionManager::getDatasource('test');
+		$schema = $db->config['schema'];
+		$Article = new Article();
+
+		$this->Dbo = $this->getMock('Postgres', array('execute'), array($db->config));
+
+		$this->Dbo->expects($this->at(0))->method('execute')
+			->with("DELETE FROM \"$schema\".\"articles\"");
+		$this->Dbo->truncate($Article);
+
+		$this->Dbo->expects($this->at(0))->method('execute')
+			->with("DELETE FROM \"$schema\".\"articles\"");
+		$this->Dbo->truncate('articles');
+
+		// #2355: prevent duplicate prefix
+		$this->Dbo->config['prefix'] = 'tbl_';
+		$Article->tablePrefix = 'tbl_';
+		$this->Dbo->expects($this->at(0))->method('execute')
+			->with("DELETE FROM \"$schema\".\"tbl_articles\"");
+		$this->Dbo->truncate($Article);
+
+		$this->Dbo->expects($this->at(0))->method('execute')
+			->with("DELETE FROM \"$schema\".\"tbl_articles\"");
+		$this->Dbo->truncate('articles');
+	}
+
 }