Adjust exclude rules filtering to avoid passing null to strlen() to fix PHP 8 deprecation notice

[ocean90]

Fixes #1349.

This fixes a deprecation notice in PHP 8:

PHP Deprecated: strlen(): Passing null to parameter #1 ($string) of type string is deprecated in classes/class-log.php on line 217

The value of my exclude rule was:

Array
(
    [connector] =>
    [context] =>
    [action] =>
    [ip_address] => 127.0.0.1
    [author] =>
    [role] =>
)

The fix is to check for null first.

Checklist

• Project documentation has been updated to reflect the changes in this pull request, if applicable.
• I have tested the changes in the local development environment (see contributing.md).
• I have added phpunit tests.

Release Changelog

• Fix: Avoid deprecation notices in PHP 8.

Release Checklist

• This pull request is to the master branch.
• Release version follows semantic versioning. Does it include breaking changes?
• Update changelog in readme.txt.
• Bump version in stream.php.
• Bump Stable tag in readme.txt.
• Bump version in classes/class-plugin.php.
• Draft a release on GitHub.

Change [ ] to [x] to mark the items as done.

[kasparsd]

Thanks for the pull request @ocean90!

It appears that the proposed change also adjusts the business logic -- could we update it to keep the previous logic, please?

[kasparsd]

This logic now allows null values to be included in the filtered output:

$list = [ 1, 'two', false, null, 0 ];

$rules = array_filter(
    $list,
    function ( $value ) {
        return null === $value || strlen( (string) $value ) > 0;
    }
);

var_dump( $rules );

returns:

array(4) {
  [0]=>
  int(1)
  [1]=>
  string(3) "two"
  [3]=>
  NULL
  [4]=>
  int(0)
}

while we would expect the null value to be removed.

Could we change this to strlen( (string) $value ) > 0?

[ocean90]

I think you're reading the previous logic wrong. Previously null was also allowed which is why I added the specific check for null. Removing that would actually be a change in the logic.