From 95ead5ae752d0b4c7ec693a2673ac24735609a04 Mon Sep 17 00:00:00 2001
From: Unlink <miso250593@gmail.com>
Date: Thu, 2 Jun 2016 12:46:23 +0200
Subject: [PATCH] ResultSet: improved error message on duplicated names in
 select statement

---
 src/Database/Helpers.php              | 28 +++++++++++++++++++++++++++
 src/Database/ResultSet.php            |  3 ++-
 tests/Database/ResultSet.fetch().phpt | 19 +++++++++++++++++-
 tests/Database/Table/Table.join.phpt  |  4 ++--
 4 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/src/Database/Helpers.php b/src/Database/Helpers.php
index c7e76f32d..7be001b5e 100644
--- a/src/Database/Helpers.php
+++ b/src/Database/Helpers.php
@@ -267,4 +267,32 @@ 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']) ? $meta['table'] : '';
+			if (isset($cols[$meta['name']])) {
+				$cols[$meta['name']][] = $tableName;
+			}
+			else {
+				$cols[$meta['name']] = [$tableName];
+			}
+		}
+		$duplicates = '';
+		foreach ($cols as $name => $tables) {
+			if (count($tables) > 1) {
+				$duplicates .= ($duplicates === '' ? '' : '; ')."'$name'".(($tmp = implode(', ', array_unique($tables))) != '' ? " from $tmp" : '');
+			}
+		}
+		return $duplicates;
+	}
+
 }
diff --git a/src/Database/ResultSet.php b/src/Database/ResultSet.php
index deeeffadb..84a7c11ae 100644
--- a/src/Database/ResultSet.php
+++ b/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);
 		}
 
 		$this->resultKey++;
diff --git a/tests/Database/ResultSet.fetch().phpt b/tests/Database/ResultSet.fetch().phpt
index 1dbac5a36..584490999 100644
--- a/tests/Database/ResultSet.fetch().phpt
+++ b/tests/Database/ResultSet.fetch().phpt
@@ -17,7 +17,7 @@ test(function () use ($context) {
 
 	Assert::error(function () use ($res) {
 		$res->fetch();
-	}, E_USER_NOTICE, 'Found duplicate columns in database result set.');
+	}, E_USER_NOTICE);
 
 	$res->fetch();
 });
@@ -35,3 +35,20 @@ test(function () use ($context, $driverName) { // tests closeCursor()
 		foreach ($res as $row) {}
 	}
 });
+
+test(function () use ($context, $driverName) {
+
+	$result = $context->query('SELECT book.id, author.id, author.name, translator.name FROM book JOIN author ON (author.id = book.author_id) JOIN author translator ON (translator.id = book.translator_id)');
+	if ($driverName == 'mysql') {
+		$errorMsg = "'id' from book, author; 'name' from author, translator";
+	}
+	else if ($driverName == 'sqlite') {
+		$errorMsg = "'id' from book, author; 'name' from author";
+	}
+	else {
+		$errorMsg = "'id'; 'name'";
+	}
+	Assert::error(function() use($result) {
+		iterator_to_array($result);
+	}, E_USER_NOTICE, "Found duplicate columns in database result set: $errorMsg.");
+});
diff --git a/tests/Database/Table/Table.join.phpt b/tests/Database/Table/Table.join.phpt
index cd100ee5c..cf06abd5d 100644
--- a/tests/Database/Table/Table.join.phpt
+++ b/tests/Database/Table/Table.join.phpt
@@ -82,7 +82,7 @@ test(function () use ($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);
 });