Using Buffer for Resultset::rewind() after Resultset::next() called in Zend\Db

In Zend\Db, there is Resultset which can be used as result of db records as instanceof PHP Iterator. For example, we have the following table structure:

CREATE TABLE test (
    id serial NOT NULL PRIMARY KEY,
    name character varying(255)
);

and we have the following data:

To build resultset, we can use the following code:

include './vendor/autoload.php';

use Zend\Db\Adapter\Adapter;
use Zend\Db\TableGateway\TableGateway;
use Zend\Db\ResultSet\ResultSet;

$adapter = new Adapter([
    'username' => 'developer',
    'password' => '123456',
    'driver'   => 'pdo_pgsql',
    'database' => 'learn',
    'host'     => 'localhost',
]);

$resultSetPrototype = new ResultSet(
    null,
    new ArrayObject([], ArrayObject::ARRAY_AS_PROPS)
);

$tableGateway = new TableGateway(
    'test',
    $adapter,
    null,
    $resultSetPrototype
);

$select    = $tableGateway->getSql()->select();
$resultSet = $tableGateway->selectWith($select);

On getting the data, we can go to specific record position by using next(), for example: we want to get the 2nd record of selected data, we can use the following code:

$resultSet->current();
$resultSet->next();

var_dump($resultSet->current());

and we will get the following data:

class ArrayObject#16 (1) {
  private $storage =>
  array(2) {
    'id' =>
    int(2)
    'name' =>
    string(6) "test 2"
  }
}

However, when we need to back to first position, we can’t just use rewind() as follow:

$resultSet->rewind();
var_dump($resultSet->current());

Above code will result wrong data, which is a next record data:

class ArrayObject#16 (1) {
  private $storage =>
  array(2) {
    'id' =>
    int(3)
    'name' =>
    string(6) "test 3"
  }
}

To make that work, we need to use buffer() method early after result set created, so, the code will need to be:

$select    = $tableGateway->getSql()->select();
$resultSet = $tableGateway->selectWith($select);

$resultSet->buffer();

$resultSet->current();  // ensure hit 1st record first 
$resultSet->next();     // next position

var_dump($resultSet->current()); // get 2nd record 

$resultSet->rewind(); // back to position 0
var_dump($resultSet->current());  // get 1st record again 

That will show the correct data:

# second record by call of next()
class ArrayObject#16 (1) {
  private $storage =>
  array(2) {
    'id' =>
    int(2)
    'name' =>
    string(6) "test 2"
  }
}

# first record after call of rewind() 
class ArrayObject#16 (1) {
  private $storage =>
  array(2) {
    'id' =>
    int(1)
    'name' =>
    string(6) "test 1"
  }
}