Make array_map() accept null as first argument

Author: jlherren

src/Reflection/ParametersAcceptorSelector.php

@@ -12,7 +12,9 @@
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Generic\TemplateTypeMap;
 use PHPStan\Type\MixedType;
+use PHPStan\Type\NullType;
 use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\UnionType;
 
 /** @api */
 class ParametersAcceptorSelector
@@ -80,7 +82,10 @@ public static function selectFromArgs(
 				$parameters[0] = new NativeParameterReflection(
 					$parameters[0]->getName(),
 					$parameters[0]->isOptional(),
-					new CallableType($callbackParameters, new MixedType(), false),
+					new UnionType([
+						new CallableType($callbackParameters, new MixedType(), false),
+						new NullType(),
+					]),
 					$parameters[0]->passedByReference(),
 					$parameters[0]->isVariadic(),
 					$parameters[0]->getDefaultValue()

src/Type/Php/ArrayMapFunctionReturnTypeExtension.php

@@ -9,9 +9,11 @@
 use PHPStan\Type\Accessory\NonEmptyArrayType;
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
+use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\NeverType;
+use PHPStan\Type\NullType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
 use PHPStan\Type\TypeUtils;
@@ -30,23 +32,35 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 			return ParametersAcceptorSelector::selectSingle($functionReflection->getVariants())->getReturnType();
 		}
 
-		$valueType = new MixedType();
+		$singleArrayArgument = !isset($functionCall->getArgs()[2]);
 		$callableType = $scope->getType($functionCall->getArgs()[0]->value);
+		$callableIsNull = (new NullType())->isSuperTypeOf($callableType)->yes();
+
 		if ($callableType->isCallable()->yes()) {
 			$valueType = new NeverType();
 			foreach ($callableType->getCallableParametersAcceptors($scope) as $parametersAcceptor) {
 				$valueType = TypeCombinator::union($valueType, $parametersAcceptor->getReturnType());
 			}
+		} elseif ($callableIsNull) {
+			$arrayBuilder = ConstantArrayTypeBuilder::createEmpty();
+			foreach (array_slice($functionCall->getArgs(), 1) as $index => $arg) {
+				$arrayBuilder->setOffsetValueType(
+					new ConstantIntegerType($index),
+					$scope->getType($arg->value)->getIterableValueType()
+				);
+			}
+			$valueType = $arrayBuilder->getArray();
+		} else {
+			$valueType = new MixedType();
 		}
 
-		$mappedArrayType = new ArrayType(
-			new MixedType(),
-			$valueType
-		);
 		$arrayType = $scope->getType($functionCall->getArgs()[1]->value);
-		$constantArrays = TypeUtils::getConstantArrays($arrayType);
 
-		if (!isset($functionCall->getArgs()[2])) {
+		if ($singleArrayArgument) {
+			if ($callableIsNull) {
+				return $arrayType;
+			}
+			$constantArrays = TypeUtils::getConstantArrays($arrayType);
 			if (count($constantArrays) > 0) {
 				$arrayTypes = [];
 				foreach ($constantArrays as $constantArray) {
@@ -66,6 +80,11 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 					$arrayType->getIterableKeyType(),
 					$valueType
 				), ...TypeUtils::getAccessoryTypes($arrayType));
+			} else {
+				$mappedArrayType = new ArrayType(
+					new MixedType(),
+					$valueType
+				);
 			}
 		} else {
 			$mappedArrayType = TypeCombinator::intersect(new ArrayType(

tests/PHPStan/Analyser/data/array_map_multiple.php

@@ -18,4 +18,19 @@ public function doFoo(int $i, string $s): void
 		assertType('array<int, int|string>&nonEmpty', $result);
 	}
 
+	/**
+	 * @param non-empty-array<string, int> $array
+	 * @param non-empty-array<int, bool> $other
+	 */
+	public function arrayMapNull(array $array, array $other): void
+	{
+		assertType('array()', array_map(null, []));
+		assertType('array(\'foo\' => true)', array_map(null, ['foo' => true]));
+		assertType('array<int, array(1|2|3, 4|5|6)>&nonEmpty', array_map(null, [1, 2, 3], [4, 5, 6]));
+
+		assertType('array<string, int>&nonEmpty', array_map(null, $array));
+		assertType('array<int, array(int, int)>&nonEmpty', array_map(null, $array, $array));
+		assertType('array<int, array(int, bool)>&nonEmpty', array_map(null, $array, $other));
+	}
+
 }

tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php

@@ -796,7 +796,7 @@ public function testArrayMapMultiple(bool $checkExplicitMixed): void
 		$this->checkExplicitMixed = $checkExplicitMixed;
 		$this->analyse([__DIR__ . '/data/array_map_multiple.php'], [
 			[
-				'Parameter #1 $callback of function array_map expects callable(1|2, \'bar\'|\'foo\'): mixed, Closure(int, int): void given.',
+				'Parameter #1 $callback of function array_map expects (callable(1|2, \'bar\'|\'foo\'): mixed)|null, Closure(int, int): void given.',
 				58,
 			],
 		]);
@@ -840,11 +840,11 @@ public function testBug5356(): void
 
 		$this->analyse([__DIR__ . '/data/bug-5356.php'], [
 			[
-				'Parameter #1 $callback of function array_map expects callable(string): mixed, Closure(array): \'a\' given.',
+				'Parameter #1 $callback of function array_map expects (callable(string): mixed)|null, Closure(array): \'a\' given.',
 				13,
 			],
 			[
-				'Parameter #1 $callback of function array_map expects callable(string): mixed, Closure(array): \'a\' given.',
+				'Parameter #1 $callback of function array_map expects (callable(string): mixed)|null, Closure(array): \'a\' given.',
 				21,
 			],
 		]);
@@ -854,7 +854,7 @@ public function testBug1954(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-1954.php'], [
 			[
-				'Parameter #1 $callback of function array_map expects callable(1|stdClass): mixed, Closure(string): string given.',
+				'Parameter #1 $callback of function array_map expects (callable(1|stdClass): mixed)|null, Closure(string): string given.',
 				7,
 			],
 		]);

tests/PHPStan/Rules/Functions/data/array_map_multiple.php

@@ -60,4 +60,9 @@ public function doFoo(): void
 		}, [1, 2], ['foo', 'bar']);
 	}
 
+	public function arrayMapNull(): void
+	{
+		array_map(null, [1, 2], [3, 4]);
+	}
+
 }