fetchSingle returns FALSE

src/Dibi/DataSource.php

@@ -161,7 +161,7 @@ class DataSource implements IDataSource
 
 	/**
 	 * Like fetch(), but returns only first field.
-	 * @return mixed  value on success, null if no next record
+	 * @return mixed  value on success, false if no next record
 	 */
 	public function fetchSingle()
 	{

src/Dibi/Fluent.php

@@ -311,7 +311,7 @@ class Fluent implements IDataSource
 
 	/**
 	 * Like fetch(), but returns only first field.
-	 * @return mixed  value on success, null if no next record
+	 * @return mixed  value on success, false if no next record
 	 */
 	public function fetchSingle()
 	{

src/Dibi/Result.php

@@ -179,13 +179,13 @@ class Result implements IDataSource
 
 	/**
 	 * Like fetch(), but returns only first field.
-	 * @return mixed value on success, null if no next record
+	 * @return mixed value on success, false if no next record
 	 */
 	final public function fetchSingle()
 	{
 		$row = $this->getResultDriver()->fetch(true);
 		if ($row === null) {
-			return null;
+			return false;
 		}
 		$this->fetched = true;
 		$this->normalize($row);

tests/dibi/Connection.fetch.phpt

@@ -18,6 +18,9 @@ $conn->loadFile(__DIR__ . "/data/$config[system].sql");
 // fetch a single value
 $res = $conn->query('SELECT [title] FROM [products] ORDER BY [product_id]');
 Assert::same('Chair', $res->fetchSingle());
+Assert::same('Table', $res->fetchSingle());
+Assert::same('Computer', $res->fetchSingle());
+Assert::false($res->fetchSingle());
 
 
 // fetch complete result set