Row: compatibility with operator ??

Author: dg

src/Database/Row.php

@@ -24,6 +24,12 @@ public function __get($key)
 	}
 
 
+	public function __isset($key)
+	{
+		return isset($this->key);
+	}
+
+
 	/**
 	 * Returns a item.
 	 * @param  string|int  $key  key or index

tests/Database/Row.phpt

@@ -17,12 +17,15 @@ test(function () use ($connection) { // numeric field
 	Assert::same(123, $row->{123});
 	Assert::same(123, $row->{'123'});
 	Assert::true(isset($row->{123}));
+	Assert::same(123, $row->{123} ?? 'default');
 	Assert::false(isset($row->{1}));
+	Assert::same('default', $row->{1} ?? 'default');
+	Assert::same('default', $row->nullcol ?? 'default');
 
 	Assert::same(123, $row[0]);
 	Assert::true(isset($row[0]));
 	Assert::false(isset($row[123]));
-	//Assert::false(isset($row['0'])); // this is buggy since PHP 5.4 (bug #63217)
+	Assert::false(isset($row['0']));
 	Assert::false(isset($row[1])); // null value
 	Assert::false(isset($row[2])); // is not set