preg_split sometimes returns array of arrays

[spaze]

When PREG_SPLIT_OFFSET_CAPTURE flag is given

preg_split('/-/', 'a-b-c', -1, PREG_SPLIT_OFFSET_CAPTURE);

See https://3v4l.org/B4Qf5

Then "this changes the return value in an array where every element is an array consisting of the matched string at offset 0 and its string offset into subject at offset 1."

[dktapps]

Wouldn't a dynamic return type extension be better for this?

[ondrejmirtes]

Thank you, but yes, dynamic return type extension would be better so that the user doesn't have to check against values that cannot occur in their situation :)

@spaze I'm sure you won't have any problems writing one as you've already written some custom PHPStan rules :) Here are some pointers:

* Basic info: https://phpstan.org/developing-extensions/dynamic-return-type-extensions

• This is a similar extension that also reads various constants (although it's probably much more complicated than one needed for preg_split: https://github.com/phpstan/phpstan-src/blob/master/src/Type/Php/FilterVarDynamicReturnTypeExtension.php
• This is a useful method:

  phpstan-src/src/Type/Php/FilterVarDynamicReturnTypeExtension.php

  Lines 75 to 84 in 4f152b2

  	private function getConstant(string $constantName): int
  	{
  	$constant = $this->reflectionProvider->getConstant(new Node\Name($constantName), null);
  	$valueType = $constant->getValueType();
  	if (!$valueType instanceof ConstantIntegerType) {
  	throw new \PHPStan\ShouldNotHappenException(sprintf('Constant %s does not have integer type.', $constantName));
  	}
  	return $valueType->getValue();
  	}

  (feel free to copy it to your extension as well)
• I'm not sure if preg_split flags can be combined using bitwise operators, if yes then the extension has to account for it.
• Test the implementation by adding a new data provider to NodeScopeResolverTest::testFileAsserts, call assertType in the test file and test various inputs :)

[spaze]

Thanks, I've vaguely remembered there was a better way of doing things like this but...

I've now changed this PR to use a dynamic type extension for that.

And thanks @ondrejmirtes for those hints, helped a lot!

[ondrejmirtes]

Perfect, thank you :)

[spaze]

Thanks for the release @ondrejmirtes! :-)