current symfony returns false not sure if null was returned in older version so I did switch to using ! instead for checking for false or null.

There is a default value that can be set in addOption. Without an explicit value it is null.

https://github.com/symfony/console/blob/5.x/Command/Command.php#L400

It seems to be the same in 4.0 and 3.0.

Seems like its not possible to set a default value for InputOption::VALUE_NONE: https://github.com/symfony/console/blob/356c70659d6b48595f9f275cd7c4de0d5544c49c/Input/InputOption.php#L168

So I could go with:

$input->getOption('complete') === true

$input->getOption('complete') !== false

or the current version.

The value of the input is set here to true:
https://github.com/symfony/console/blob/356c70659d6b48595f9f275cd7c4de0d5544c49c/Input/ArgvInput.php#L248

And default value to false:

https://github.com/symfony/console/blob/356c70659d6b48595f9f275cd7c4de0d5544c49c/Input/InputOption.php#L182

If it's a boolean then your current syntax should fit. You currently let it step into the if-block when the value is false. It also looks like there are no tests yet that covers this class. Can you please create one that covers your changes?

@SenseException created the missing test class hope it matches how tests are created in this repository.