RegexArrayShapeMatcher - Support 'n' modifier

Author: staabm

src/Php/PhpVersion.php

@@ -316,6 +316,12 @@ public function supportsPregUnmatchedAsNull(): bool
 		return $this->versionId >= 70400;
 	}
 
+	public function supportsPregCaptureOnlyNamedGroups(): bool
+	{
+		// https://php.watch/versions/8.2/preg-n-no-capture-modifier
+		return $this->versionId >= 80200;
+	}
+
 	public function hasDateTimeExceptions(): bool
 	{
 		return $this->versionId >= 80300;

src/Type/Php/RegexArrayShapeMatcher.php

@@ -33,6 +33,7 @@
 use function is_string;
 use function rtrim;
 use function sscanf;
+use function str_contains;
 use function str_replace;
 use function strlen;
 use function substr;
@@ -411,6 +412,12 @@ private function parseGroups(string $regex): ?array
 			return null;
 		}
 
+		$captureOnlyNamed = false;
+		if ($this->phpVersion->supportsPregCaptureOnlyNamedGroups()) {
+			$modifiers = $this->regexExpressionHelper->getPatternModifiers($regex);
+			$captureOnlyNamed = str_contains($modifiers ?? '', 'n');
+		}
+
 		$capturingGroups = [];
 		$groupCombinations = [];
 		$alternationId = -1;
@@ -427,6 +434,7 @@ private function parseGroups(string $regex): ?array
 			$capturingGroups,
 			$groupCombinations,
 			$markVerbs,
+			$captureOnlyNamed,
 		);
 
 		return [$capturingGroups, $groupCombinations, $markVerbs];
@@ -448,6 +456,7 @@ private function walkRegexAst(
 		array &$capturingGroups,
 		array &$groupCombinations,
 		array &$markVerbs,
+		bool $captureOnlyNamed,
 	): void
 	{
 		$group = null;
@@ -509,7 +518,10 @@ private function walkRegexAst(
 			return;
 		}
 
-		if ($group instanceof RegexCapturingGroup) {
+		if (
+			$group instanceof RegexCapturingGroup &&
+			(!$captureOnlyNamed || $group->isNamed())
+		) {
 			$capturingGroups[$group->getId()] = $group;
 
 			if (!array_key_exists($alternationId, $groupCombinations)) {
@@ -533,6 +545,7 @@ private function walkRegexAst(
 				$capturingGroups,
 				$groupCombinations,
 				$markVerbs,
+				$captureOnlyNamed,
 			);
 
 			if ($ast->getId() !== '#alternation') {

src/Type/Php/RegexExpressionHelper.php

@@ -10,6 +10,7 @@
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
+use function strrpos;
 use function substr;
 
 final class RegexExpressionHelper
@@ -68,6 +69,27 @@ public function resolve(Expr $expr): Type
 		return $this->initializerExprTypeResolver->getConcatType($concat->left, $concat->right, static fn (Expr $expr): Type => $resolver->resolve($expr));
 	}
 
+	public function getPatternModifiers(string $pattern): ?string
+	{
+		$delimiter = $this->getDelimiterFromString(new ConstantStringType($pattern));
+		if ($delimiter === null) {
+			return null;
+		}
+
+		if ($delimiter === '{') {
+			$endDelimiterPos = strrpos($pattern, '}');
+		} else {
+			// same start and end delimiter
+			$endDelimiterPos = strrpos($pattern, $delimiter);
+		}
+
+		if ($endDelimiterPos === false) {
+			return null;
+		}
+
+		return substr($pattern, $endDelimiterPos + 1);
+	}
+
 	/**
 	 * Get delimiters from non-constant patterns, if possible.
 	 *

tests/PHPStan/Analyser/nsrt/preg_match_shapes_php82.php

@@ -8,12 +8,17 @@
 // https://php.watch/versions/8.2/preg-n-no-capture-modifier
 function doNonAutoCapturingFlag(string $s): void {
 	if (preg_match('/(\d+)/n', $s, $matches)) {
-		assertType('array{string, numeric-string}', $matches); // should be 'array{string}'
+		assertType('array{string}', $matches);
 	}
-	assertType('array{}|array{string, numeric-string}', $matches);
+	assertType('array{}|array{string}', $matches);
 
 	if (preg_match('/(\d+)(?P<num>\d+)/n', $s, $matches)) {
-		assertType('array{0: string, 1: numeric-string, num: numeric-string, 2: numeric-string}', $matches);
+		assertType('array{0: string, num: numeric-string, 1: numeric-string}', $matches);
 	}
-	assertType('array{}|array{0: string, 1: numeric-string, num: numeric-string, 2: numeric-string}', $matches);
+	assertType('array{}|array{0: string, num: numeric-string, 1: numeric-string}', $matches);
+
+	if (preg_match('/(\w)-(?P<num>\d+)-(\w)/n', $s, $matches)) {
+		assertType('array{0: string, num: numeric-string, 1: numeric-string}', $matches);
+	}
+	assertType('array{}|array{0: string, num: numeric-string, 1: numeric-string}', $matches);
 }