ResultSet: improved error message on duplicated names in select statement

Author: Unlink

src/Database/Helpers.php

@@ -267,4 +267,28 @@ public static function toPairs(array $rows, $key = NULL, $value = NULL)
 		return $return;
 	}
 
+
+	/**
+	 * Finds duplicate columns in select statement
+	 * @param \PDOStatement
+	 * @return string
+	 */
+	public static function findDuplicates(\PDOStatement $statement)
+	{
+		$cols = [];
+		for ($i=0; $i<$statement->columnCount(); $i++) {
+			$meta = $statement->getColumnMeta($i);
+			$tableName = isset($meta['table']) ? $meta['table'] : '';
+				$cols[$meta['name']][] = $tableName;
+		}
+		$duplicates = [];
+		foreach ($cols as $name => $tables) {
+			if (count($tables) > 1) {
+				$tableNames = implode(', ', array_unique($tables));
+				$duplicates[] = "'$name'".($tableNames !== '' ? " from $tableNames" : '');
+			}
+		}
+		return implode('; ', $duplicates);
+	}
+
 }

src/Database/ResultSet.php

@@ -266,7 +266,8 @@ public function fetch()
 		}
 
 		if ($this->result === NULL && count($data) !== $this->pdoStatement->columnCount()) {
-			trigger_error('Found duplicate columns in database result set.', E_USER_NOTICE);
+			$duplicates = Helpers::findDuplicates($this->pdoStatement);
+			trigger_error("Found duplicate columns in database result set: $duplicates.", E_USER_NOTICE);
 		}
 
 		$this->resultKey++;

tests/Database/ResultSet.fetch().phpt

@@ -17,7 +17,7 @@ test(function () use ($context) {
 
 	Assert::error(function () use ($res) {
 		$res->fetch();
-	}, E_USER_NOTICE, 'Found duplicate columns in database result set.');
+	}, E_USER_NOTICE);
 
 	$res->fetch();
 });
@@ -35,3 +35,12 @@ test(function () use ($context, $driverName) { // tests closeCursor()
 		foreach ($res as $row) {}
 	}
 });
+
+test(function () use ($context, $driverName) {
+
+	$result = $context->query('SELECT book.id, author.id, author.name, translator.name FROM book JOIN author ON (author.id = book.author_id) JOIN author translator ON (translator.id = book.translator_id)');
+	//Found duplicate columns in database result set: 'id' from book, author; 'name' from author, translator.
+	Assert::error(function() use($result) {
+		iterator_to_array($result);
+	}, E_USER_NOTICE);
+});

tests/Database/Table/Table.join.phpt

@@ -82,7 +82,7 @@ test(function () use ($context) {
 });
 
 
-test(function () use ($connection, $structure) {
+test(function () use ($connection, $structure, $driverName) {
 	$context = new Nette\Database\Context(
 		$connection,
 		$structure,
@@ -92,5 +92,5 @@ test(function () use ($connection, $structure) {
 	$books = $context->table('book')->select('book.*, author.name, translator.name');
 	Assert::error(function() use($books) {
 		iterator_to_array($books);
-	}, E_USER_NOTICE, 'Found duplicate columns in database result set.');
+	}, E_USER_NOTICE);
 });