Bleeding edge - Precise array shape for preg_replace_callback() $matches

[staabm]

will do preg_replace_callback_array in a separate PR

[staabm]

//cc @Seldaek @mvorisek

[phpstan-bot]

This pull request has been marked as ready for review.

[ondrejmirtes]

Thank you.

[ondrejmirtes]

Could/should this be improved? https://phpstan.org/r/de0085e1-29c0-4346-849a-79948ec1c385

It's code from phpdoc-parser and copied from PHP-Parser I think, of course I don't understand it at all.

[Seldaek]

Sounds feasible in theory to me, as you have a branch of the match group 1 which is "u", but that'd require a way to have partially static strings where you can look up index 0 and if index0 is known then we return it if not then it's just string or ''. That part you have to say if feasible.

[staabm]

I don't understand the regex either but I hope I got you right:

we would need dependent types, because $matches[2] only always exists after if ($str[0] === 'u') - right?
I think this kind of dependent type is not even possible in the plain PHPStan type-system (a type depending on the offset of a string)?

[ondrejmirtes]

Not dependent types, but something that is called tagged unions. Those are supported: https://phpstan.org/r/90cb0d94-b149-4b37-8c20-e5f7d984a160

Do you think the type here can be expressed like that?

[staabm]

oh I see. I think we do similar things already in

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

Lines 130 to 206 in 4755b37

	$onlyOptionalTopLevelGroup = $this->getOnlyOptionalTopLevelGroup($groupList);
	$onlyTopLevelAlternationId = $this->getOnlyTopLevelAlternationId($groupList);
	if (
	!$matchesAll
	&& $wasMatched->yes()
	&& $onlyOptionalTopLevelGroup !== null
	) {
	// if only one top level capturing optional group exists
	// we build a more precise constant union of a empty-match and a match with the group
	$onlyOptionalTopLevelGroup->forceNonOptional();
	$combiType = $this->buildArrayType(
	$groupList,
	$wasMatched,
	$trailingOptionals,
	$flags ?? 0,
	$markVerbs,
	$matchesAll,
	);
	if (!$this->containsUnmatchedAsNull($flags ?? 0, $matchesAll)) {
	$combiType = TypeCombinator::union(
	new ConstantArrayType([new ConstantIntegerType(0)], [new StringType()], [0], [], true),
	$combiType,
	);
	}
	return $combiType;
	} elseif (
	!$matchesAll
	&& $wasMatched->yes()
	&& $onlyTopLevelAlternationId !== null
	&& array_key_exists($onlyTopLevelAlternationId, $groupCombinations)
	) {
	$combiTypes = [];
	$isOptionalAlternation = false;
	foreach ($groupCombinations[$onlyTopLevelAlternationId] as $groupCombo) {
	$comboList = $groupList;
	$beforeCurrentCombo = true;
	foreach ($comboList as $groupId => $group) {
	if (in_array($groupId, $groupCombo, true)) {
	$isOptionalAlternation = $group->inOptionalAlternation();
	$group->forceNonOptional();
	$beforeCurrentCombo = false;
	} elseif ($beforeCurrentCombo && !$group->resetsGroupCounter()) {
	$group->forceNonOptional();
	} elseif ($group->getAlternationId() === $onlyTopLevelAlternationId && !$this->containsUnmatchedAsNull($flags ?? 0, $matchesAll)) {
	unset($comboList[$groupId]);
	}
	}
	$combiType = $this->buildArrayType(
	$comboList,
	$wasMatched,
	$trailingOptionals,
	$flags ?? 0,
	$markVerbs,
	$matchesAll,
	);
	$combiTypes[] = $combiType;
	foreach ($groupCombo as $groupId) {
	$group = $comboList[$groupId];
	$group->restoreNonOptional();
	}
	}
	if ($isOptionalAlternation && !$this->containsUnmatchedAsNull($flags ?? 0, $matchesAll)) {
	$combiTypes[] = new ConstantArrayType([new ConstantIntegerType(0)], [new StringType()], [0], [], true);
	}
	return TypeCombinator::union(...$combiTypes);
	}

I will have a look