Mixed Enum values should not be accepted

[tuscanicz]

You can now define following Enum as you can see in AbstractEnumTest::testConstructWithMixed():

class EntityStatusEnum extends AbstractEnum
{

    public const NEW_ENTITY = 'new';
    public const MODIFIED_ENTITY = 2;
    public const SAVED_ENTITY = 'saved';

}

This is fully supported and can cause some issues in integrations.

You can also set value to a null, but the Enum will behave very unpredictably with default value. You can see such an example in AbstractEnumTest ::testConstructWithNullAndMixed().

class EntityStatusMixedTypeWithNullEnum extends AbstractEnum
{

    public const NEW_ENTITY = null;
    public const MODIFIED_ENTITY = 2;
    public const SAVED_ENTITY = 'saved';
    public const DEFAULT_ENTITY_STATUS = 'default-value';

    protected static $defaultValue = self::DEFAULT_ENTITY_STATUS;

}

The goal is to avoid:

• mixed values of Enums, which will bring even more stricter behavior from which a developer can benefit
• null values and default values must not be used anymore, because they cause confusion