fix(entity): explicitly set userId to null in OAuthAccessToken constructor

[dq042000]

When using grant_type=client_credentials, the userIdentifier is null.
This caused an error in OAuthAccessToken::getUserIdentifier():

Typed property Core\Security\Entity\OAuthAccessToken::$userId must not be accessed before initialization

To fix this, I updated OAuthAccessToken.php by explicitly initializing $userId to null in the __construct() method.

[Copilot]

Pull Request Overview

This PR fixes a PHP error that occurs when using OAuth2 client credentials grant where no user is associated with the access token. The error was caused by accessing an uninitialized typed property.

• Explicitly initializes the $userId property to null in the OAuthAccessToken constructor
• Prevents "Typed property must not be accessed before initialization" errors when getUserIdentifier() is called on tokens created via client credentials grant

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[alexmerlin]

Hey @dq042000

Commit was not correctly signed off.
Click on DCO on see the DCO page for instructions on how to fix it.

[dq042000]

Hi @alexmerlin

Thanks! I’ve updated the commits with the proper Signed-off-by and the DCO check is now passing.

[alexmerlin]

@dq042000 Could you move the initialization from the constructor to the property itself?
It should work the same and the initialization would align better with the rest of the code, since we already declare the property as nullable.

So:

private ?string $userId = null;

instead of:

private ?string $userId;

[dq042000]

@alexmerlin

Thanks for pointing that out! You’re right — initializing the property directly makes the code cleaner and more consistent. I’ve updated the commit accordingly.

[alexmerlin]

Thanks @dq042000