CURL progress callback and RemoveUnusedPrivateMethodParameterRector

[jraller]

When using CURL's curl_setopt($resource, CURLOPT_PROGRESSFUNCTION, 'progressCallback'); to have a callback to monitor progress of a CURL call the callback function is supposed to have a signature like:

private function progressCallback($resource, $download_size = 0, $downloaded = 0, $upload_size = 0, $uploaded = 0)
{
    // Handle progress
}

If I'm only utilizing the $download_size and $downloaded portions of that call. The rector rule RemoveUnusedPrivateMethodParameterRector will remove the unused parameters, and then the callback will not match the expected form and an error will be thrown.

By changing from private to protected I avoid those being removed because there isn't a rector rule for RemoveUnusedProtected...

Is there a way to keep the function private and to keep the rule in place and have the rule not act on private callback functions where the signature of the function is controlled by code that you can't change? Or is the correct way to handle this to mark the method as protected?

[samsonasik]

Could you create sample code at https://getrector.com/demo show what expected and what should happen? Thank you

[jraller]

https://getrector.com/demo/9465cef8-d1b3-4bc2-b235-57875ced28cf shows the behavior.

I suspect that rector is doing the correct thing, but I'd like to understand if this is an edge case or just one where the user needs to know to use protected instead of private in order to retain the unused parameters. Alternatively if there is a way I should be using annotation or attributes on that method to indicate that it is matching an external callback signature I'd like to learn about the correct way to do that.

[samsonasik]

I see, I think you can just skip it for this case, since verify callback usage will probably cause performance drawback for rare usage, alternatively, you can make it protected or, make Closure::fromCallable or inner function for it, eg

https://getrector.com/demo/bd86c79b-34f9-4668-b698-f2921e1861e0

[jraller]

Another way to handle it that appears to work would be to write the callback signature like:

function progressCallback(...$params):void {
    list($ignore, $size, $done) = $params;
    echo $done / $size . PHP_EOL;
}

which hides the unused parameters from view.