I think most of those changes are BC. I've done already a lot of work to clean filters for ZF3 (#5097), maybe you could directly do PR to my branch so that those changes are also included in the refactor branch? What do you think?

@bakura10 most of the changes are definetly no BC breaks.

The only difference is, that there is now always a check of the filtered values, before filtering and no error is triggered.
If a Filter has been used currently right, there will be no BC break.

For me both ways are okay. ZF2 or ZF3....someone else shall decide 😄

Speaking of the behavior of filters, keep this in mind.

That's an interesting thing @texdc . In fact, hydrator filters are... well... filters. They don't hydrate/extract unwanting filter. In fact, what you would want would be to rename Filter component to Sanitizer component? I'm not against this idea, however I'm wondering if it would be a good thing to do. People are accustomed to using the Zend\Filter component since... many many many years. Changing this now would indeed confuse a lot of people. Again, the tradeoff between correctness, usage and simplicity is not an easy task.

@samsonasik coding standards should be fine now. (i hope i didn't missed a spot...is there also a automatically fixer?)
@weierophinney the phunit.xml which is reverted

About the notes for the "null" check. It's the same behaviour....null is not a scalar, so it return itself (which is null)

/* original */
if (null === $value) {
    return null;
}
if (!is_scalar($value)) {
    return $value;
}

/* new */
//the same, if the value is null -> it will return null...
if (!is_scalar($value)) {
    return $value;
}

_Missing_
foreach / data provider for unittests....don't know when i have time....:-/

@weierophinney all should be fine now....

about null check again: it's also tested here:

https://github.com/ThaDafinser/zf2/blob/d98e6d6aaeff9a9f907e503736389b4c950be1af/tests/ZendTest/Filter/BaseNameTest.php#L40

In my second last commit, i fixed the call in invoke.

I don't understand why null have to be passed, but i let now pass null again in my last commit.

namespace ZendTest\Filter;

use Zend\Filter\Decompress as DecompressFilter;

/**
 * @group      Zend_Filter
 */
class DecompressTest extends \PHPUnit_Framework_TestCase
    public function testCompressToFile()
    {
        $filter   = new DecompressFilter('bz2');
        $archive = __DIR__ . '/../_files/compressed.bz2';
        $filter->setArchive($archive);

        $content = $filter->compress('compress me');
        $this->assertTrue($content);

        $filter2  = new DecompressFilter('bz2');
        $content2 = $filter2($archive);
        $this->assertEquals('compress me', $content2);

        $filter3 = new DecompressFilter('bz2');
        $filter3->setArchive($archive);
        $content3 = $filter3(null);
        $this->assertEquals('compress me', $content3);
    }

@weierophinney everything fine or not?

@ThaDafinser Yes, I think so -- need to review again. (Been busy getting Apigility ready for beta...)

This would be good to have since currently adding filters in apigility causes breakage if the inputs come in as something the filters cannot deal with.

Merged to develop for release with 2.3.0.

Yiiiha :-) finally

@ThaDafinser Thanks for doing this, it solves a big problem I was having