session_start(): Failed to read session data: user (path: )

[ZhangRuiMingZRM]

• Phalcon version: 4.0.0
• PHP Version: 7.3.6
• Operating System: ubuntu
• Installation type: Compiling from source
• Server: php web server

use Phalcon\Session\Manager;
use Phalcon\Session\Adapter\Redis;
use Phalcon\Storage\AdapterFactory;

try {
    $session = new Manager();
    $adapterFactory = new AdapterFactory();
    $handler = new Redis(
        $adapterFactory,
        [
            "host" => "127.0.0.1",
            "port" => 6379
        ]
    );
    $session->setHandler($handler);
    $session->start();
} 
...

I got this

PHP Warning:  session_start(): Failed to read session data: user (path: ) in .....

That is because SessionHandlerInterface::read expect string as return value but actually return null

cphalcon/phalcon/Session/Adapter/AbstractAdapter.zep

Lines 54 to 57 in 3d76cda

	public function read(var id) -> string
	{
	return this->adapter->get(id);
	}

Phalcon\Session\Adapter\Redis::get() may return null

cphalcon/phalcon/Storage/Adapter/Redis.zep

Lines 96 to 102 in 3d76cda

	public function get(string! key, var defaultValue = null) -> var
	{
	return this->getUnserializedData(
	this->getAdapter()->get(key),
	defaultValue
	);
	}

This is a solution

in Phalcon/Session/Adapter/AbstractAdapter::read()

    public function read(var id) -> string
    {
      var data;
        let data = this->adapter->get(id);

        return is_null(data) ? "" : data;
    }

And in test unit Phalcon\Test\Integration\Session\Adapter\Redis\ReadCest::sessionAdapterRedisRead()
should add test for another possible situation (if session_id(key) does not exist in redis)

cphalcon/tests/integration/Session/Adapter/Redis/ReadCest.php

Lines 36 to 48 in 3d76cda

	public function sessionAdapterRedisRead(IntegrationTester $I)
	{
	$I->wantToTest('Session\Adapter\Redis - write()');
	$adapter = $this->getSessionRedis();
	$value = uniqid();
	$I->haveInRedis('string', 'sess-reds-test1', $value);
	$expected = $value;
	$actual = $adapter->read('test1');
	$I->assertEquals($expected, $actual);
	$I->sendCommandToRedis('del', 'sess-reds-test1');
	}

Test if session_id(key) does not exist in redis

public function sessionAdapterRedisRead(IntegrationTester $I)
{
    .
    .
    . 
   $I->sendCommandToRedis('del', 'sess-reds-test1');
   $I->assertNotNull(
           $adapter->read('test1')
   );
}

So do as Phalcon\Session\Adapter\Libmemcached::get()

[ruudboon]

Thank for reporting. Do you have time to open a pull for this? Otherwise I can do this.

[ZhangRuiMingZRM]

Thank for reporting. Do you have time to open a pull for this? Otherwise I can do this.

Very pleased to do it

[ruudboon]

Thnx!

[sergeyklay]

Fixed in the 4.0.x branch. Feel free to open a new issue if the problem appears again. Thank you for the bug report.