Fix phpstan/phpstan#14270: Regression: regex matches after checking non-empty array

src/Type/Php/PregMatchParameterOutTypeExtension.php

@@ -8,8 +8,10 @@
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Reflection\ParameterReflection;
 use PHPStan\TrinaryLogic;
+use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
 use PHPStan\Type\FunctionParameterOutTypeExtension;
 use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
 use function in_array;
 use function strtolower;
 
@@ -49,8 +51,17 @@ public function getParameterOutTypeFromFunctionCall(FunctionReflection $function
 		}
 
 		if ($functionReflection->getName() === 'preg_match') {
-			return $this->regexShapeMatcher->matchExpr($patternArg->value, $flagsType, TrinaryLogic::createMaybe(), $scope);
+			$matchedType = $this->regexShapeMatcher->matchExpr($patternArg->value, $flagsType, TrinaryLogic::createYes(), $scope);
+			if ($matchedType === null) {
+				return null;
+			}
+
+			return TypeCombinator::union(
+				ConstantArrayTypeBuilder::createEmpty()->getArray(),
+				$matchedType,
+			);
 		}
+
 		return $this->regexShapeMatcher->matchAllExpr($patternArg->value, $flagsType, TrinaryLogic::createMaybe(), $scope);
 	}
 

tests/PHPStan/Analyser/data/param-out.php

@@ -494,10 +494,10 @@ function fooMatch(string $input): void {
 	assertType('list<array{string}>', $matches);
 
 	preg_match('/@[a-z\d](?:[a-z\d]|-(?=[a-z\d])){0,38}(?!\w)/', $input, $matches, PREG_UNMATCHED_AS_NULL);
-	assertType("array{0?: string}", $matches);
+	assertType("array{}|array{non-falsy-string}", $matches);
 }
 
 function testMatch() {
 	preg_match('#.*#', 'foo', $matches);
-	assertType('array{0?: string}', $matches);
+	assertType('array{}|array{string}', $matches);
 }

tests/PHPStan/Analyser/nsrt/bug-11293.php

@@ -30,7 +30,7 @@ public function sayHello3(string $s): void
 	public function sayHello4(string $s): void
 	{
 		if (preg_match('/data-(\d{6})\.json$/', $s, $matches) <= 0) {
-			assertType('list{0?: string, 1?: non-falsy-string&numeric-string}', $matches);
+			assertType('array{}|array{non-falsy-string, non-falsy-string&numeric-string}', $matches);
 
 			return;
 		}
@@ -41,7 +41,7 @@ public function sayHello4(string $s): void
 	public function sayHello5(string $s): void
 	{
 		if (preg_match('/data-(\d{6})\.json$/', $s, $matches) < 1) {
-			assertType('list{0?: string, 1?: non-falsy-string&numeric-string}', $matches);
+			assertType('array{}|array{non-falsy-string, non-falsy-string&numeric-string}', $matches);
 
 			return;
 		}
@@ -52,7 +52,7 @@ public function sayHello5(string $s): void
 	public function sayHello6(string $s): void
 	{
 		if (1 > preg_match('/data-(\d{6})\.json$/', $s, $matches)) {
-			assertType('list{0?: string, 1?: non-falsy-string&numeric-string}', $matches);
+			assertType('array{}|array{non-falsy-string, non-falsy-string&numeric-string}', $matches);
 
 			return;
 		}

tests/PHPStan/Analyser/nsrt/bug-11311.php

@@ -191,12 +191,12 @@ function (string $s): void {
 
 function (string $s): void {
 	preg_match('/%a(\d*)/', $s, $matches, PREG_UNMATCHED_AS_NULL);
-	assertType("list{0?: string, 1?: ''|numeric-string|null}", $matches); // could be array{0?: string, 1?: ''|numeric-string}
+	assertType("array{}|array{non-falsy-string, ''|numeric-string}", $matches);
 };
 
 function (string $s): void {
 	preg_match('/%a(\d*)?/', $s, $matches, PREG_UNMATCHED_AS_NULL);
-	assertType("list{0?: string, 1?: ''|numeric-string|null}", $matches); // could be array{0?: string, 1?: ''|numeric-string}
+	assertType("array{}|array{non-falsy-string, ''|numeric-string|null}", $matches);
 };
 
 function (string $s): void {
@@ -222,5 +222,5 @@ function (string $s): void {
 
 function (string $s): void {
 	preg_match('~a|(\d)|(\s)~', $s, $matches, PREG_UNMATCHED_AS_NULL);
-	assertType("list{0?: string, 1?: numeric-string|null, 2?: non-empty-string|null}", $matches);
+	assertType("array{}|array{non-empty-string, numeric-string|null, non-empty-string|null}", $matches);
 };

tests/PHPStan/Analyser/nsrt/bug-11580.php

@@ -26,7 +26,7 @@ public function bad2(string $in): void
 	public function bad3(string $in): void
 	{
 		$result = preg_match('~^/xxx/([\w\-]+)/?([\w\-]+)?/?$~', $in, $matches);
-		assertType('list{0?: string, 1?: non-empty-string, 2?: non-empty-string}', $matches);
+		assertType('array{}|array{0: non-falsy-string, 1: non-empty-string, 2?: non-empty-string}', $matches);
 		if ($result) {
 			assertType('array{0: non-falsy-string, 1: non-empty-string, 2?: non-empty-string}', $matches);
 		}

tests/PHPStan/Analyser/nsrt/count-type.php

@@ -94,7 +94,7 @@ public function constantArrayWhichCanBecomeList(string $h): void
 			return;
 		}
 
-		assertType('array{string, non-empty-string}', $matches);
+		assertType('array{non-falsy-string, non-empty-string}', $matches);
 	}
 
 }

tests/PHPStan/Analyser/nsrt/if.php

@@ -392,7 +392,7 @@ function () {
 							assertVariableCertainty(TrinaryLogic::createYes(), $anotherF);
 							assertType('int<1, max>', $anotherF);
 							assertVariableCertainty(TrinaryLogic::createYes(), $matches);
-							assertType('array{0?: string}', $matches);
+							assertType('array{}|array{string}', $matches);
 							assertVariableCertainty(TrinaryLogic::createYes(), $anotherArray);
 							assertType('array{test: array{\'another\'}}', $anotherArray);
 							assertVariableCertainty(TrinaryLogic::createYes(), $ifVar);
@@ -405,7 +405,7 @@ function () {
 							assertType('1|2|3', $ifNotNestedVar);
 							assertVariableCertainty(TrinaryLogic::createNo(), $variableOnlyInEarlyTerminatingElse);
 							assertVariableCertainty(TrinaryLogic::createMaybe(), $matches2);
-							assertType('array{0?: string}', $matches2);
+							assertType('array{}|array{string}', $matches2);
 							assertVariableCertainty(TrinaryLogic::createYes(), $inTry);
 							assertType('1', $inTry);
 							assertVariableCertainty(TrinaryLogic::createYes(), $matches3);

tests/PHPStan/Analyser/nsrt/preg_match_shapes.php

@@ -525,15 +525,15 @@ function bug11323(string $s): void {
 
 function (string $s): void {
 	preg_match('/%a(\d*)/', $s, $matches);
-	assertType("list{0?: string, 1?: ''|numeric-string}", $matches);
+	assertType("array{}|array{non-falsy-string, ''|numeric-string}", $matches);
 };
 
 class Bug11376
 {
 	public function test(string $str): void
 	{
 		preg_match('~^(?:(\w+)::)?(\w+)$~', $str, $matches);
-		assertType('list{0?: string, 1?: string, 2?: non-empty-string}', $matches);
+		assertType("array{}|array{non-empty-string, string, non-empty-string}", $matches);
 	}
 
 	public function test2(string $str): void
@@ -706,7 +706,7 @@ static public function sayHello(string $source): void
 		//  2 => '1',
 		//)
 
-		assertType("array{0?: string, dateFrom?: ''|numeric-string, 1?: ''|numeric-string, dateTo?: numeric-string, 2?: numeric-string}", $matches);
+		assertType("array{}|array{0: string, dateFrom?: ''|numeric-string, 1?: ''|numeric-string, dateTo?: numeric-string, 2?: numeric-string}", $matches);
 	}
 }
 
@@ -730,7 +730,7 @@ function (string $s): void {
 
 function (string $s): void {
 	preg_match('~a|(\d)|(\s)~', $s, $matches);
-	assertType("list{0?: string, 1?: '', 2?: non-empty-string}|list{0?: string, 1?: numeric-string}", $matches);
+	assertType("array{}|array{0: non-empty-string, 1?: numeric-string}|array{non-empty-string, '', non-empty-string}", $matches);
 };
 
 function bug11490 (string $expression): void {
@@ -1013,7 +1013,7 @@ function bug12749f(string $str): void
 
 function bug12397(string $string): void {
 	$m = preg_match('#\b([A-Z]{2,})-(\d+)#', $string, $match);
-	assertType('list{0?: string, 1?: non-falsy-string, 2?: numeric-string}', $match);
+	assertType("array{}|array{non-falsy-string, non-falsy-string, numeric-string}", $match);
 }
 
 function bug12792(string $string): void {

tests/PHPStan/Rules/Arrays/ArrayDestructuringRuleTest.php

@@ -49,6 +49,11 @@ public function testRule(): void
 		]);
 	}
 
+	public function testBug14270(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-14270.php'], []);
+	}
+
 	#[RequiresPhp('>= 8.0')]
 	public function testRuleWithNullsafeVariant(): void
 	{

tests/PHPStan/Rules/Arrays/data/bug-14270.php

@@ -0,0 +1,14 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14270;
+
+class Foo
+{
+	public function getDuration(string $path): void {
+		preg_match('~^([a-z]+)\:\/\/(.+)~', $path, $matches);
+		$scheme = null;
+		if ($matches !== []) {
+			[, $scheme, $path] = $matches;
+		}
+	}
+}

tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php

@@ -393,4 +393,11 @@ public function testBug12973(): void
 		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-12973.php'], []);
 	}
 
+	public function testBug12397(): void
+	{
+		$this->checkNullables = true;
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-12397.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Functions/data/bug-12397.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Bug12397;
+
+/**
+ * @return list<string>
+ */
+function matchStuff(string $string) : array {
+	$m = preg_match('#\b([A-Z]{2,})-(\d+)#', $string, $match);
+	return $match;
+}