Why not set the default to empty array as you originally suggested?

Because I found a solution not breaking B/C.

Is it a B/C break? Passing NULL would have resulted in a crash?

Seems I'm confused a bit. Let's see what we have.

Initial method (from master branch):

And if I call getIterations without params I'll get TypeError as this method must return array:

$myConfig = RunnerConfig::create();
$myConfig->getIterations(); // Uncaught TypeError: PhpBench\Benchmark\RunnerConfig::getIterations(): Return value must be of type array, null returned

In #1069 I suggested this solution:

    public function getIterations(array $default = []): array
    {
        return $this->iterations ?: $default;
    }

But it's breaks B/C as some user can have the following code:

$myConfig = RunnerConfig::create();
$myConfig->getIterations(null); // Uncaught TypeError: PhpBench\Benchmark\RunnerConfig::getIterations(): Argument #1 ($default) must be of type array, null given

So to keep B/C we must not change method signature. In this PR we just check the value of $default param. And if $default === null we set it to an empty array:

As you see the signature is not changed in comparing with master branch.

And this code will keep start working:

$myConfig = RunnerConfig::create();
$myConfig->getIterations();
$myConfig->getIterations(null);

On the other hand, users couldn't have the code like this as they would get TypeError. So in theory we can consider this case as a bug and use the solution from #1069. What do you think?

yes, I think B/C is only if they could depend on this behavor, in theory they could depend on the runtime error, but that would be truly horrifying (insert XKCD here). It's a bug fix 👍

Fixed:)

thanks!