Do not report non-existent function after function_exists() check

phpstan · Nov 6, 2021 · 28e8c11 · 28e8c11
1 parent 6bb0fd6
commit 28e8c11
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Showing 7 changed files with 158 additions and 0 deletions.
diff --git a/conf/config.neon b/conf/config.neon
@@ -1306,6 +1306,11 @@ services:
 		tags:
 			- phpstan.typeSpecifier.functionTypeSpecifyingExtension
 
+	-
+		class: PHPStan\Type\Php\FunctionExistsFunctionTypeSpecifyingExtension
+		tags:
+			- phpstan.typeSpecifier.functionTypeSpecifyingExtension
+
 	-
 		class: PHPStan\Type\Php\InArrayFunctionTypeSpecifyingExtension
 		tags:

diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
@@ -2765,6 +2765,16 @@ public function isInClassExists(string $className): bool
 		return (new ConstantBooleanType(true))->isSuperTypeOf($this->getType($expr))->yes();
 	}
 
+	/** @api */
+	public function isInFunctionExists(string $functionName): bool
+	{
+		$expr = new FuncCall(new FullyQualified('function_exists'), [
+			new Arg(new String_(ltrim($functionName, '\\'))),
+		]);
+
+		return (new ConstantBooleanType(true))->isSuperTypeOf($this->getType($expr))->yes();
+	}
+
 	/** @api */
 	public function enterClass(ClassReflection $classReflection): self
 	{

diff --git a/src/Analyser/Scope.php b/src/Analyser/Scope.php
@@ -89,6 +89,8 @@ public function isSpecified(Expr $node): bool;
 
 	public function isInClassExists(string $className): bool;
 
+	public function isInFunctionExists(string $functionName): bool;
+
 	public function isInClosureBind(): bool;
 
 	public function isParameterValueNullable(Param $parameter): bool;

diff --git a/src/Rules/Functions/CallToNonExistentFunctionRule.php b/src/Rules/Functions/CallToNonExistentFunctionRule.php
@@ -39,6 +39,10 @@ public function processNode(Node $node, Scope $scope): array
 		}
 
 		if (!$this->reflectionProvider->hasFunction($node->name, $scope)) {
+			if ($scope->isInFunctionExists($node->name->toString())) {
+				return [];
+			}
+
 			return [
 				RuleErrorBuilder::message(sprintf('Function %s not found.', (string) $node->name))->discoveringSymbolsTip()->build(),
 			];

diff --git a/src/Type/Php/FunctionExistsFunctionTypeSpecifyingExtension.php b/src/Type/Php/FunctionExistsFunctionTypeSpecifyingExtension.php
@@ -0,0 +1,56 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Arg;
+use PhpParser\Node\Expr\FuncCall;
+use PhpParser\Node\Name\FullyQualified;
+use PhpParser\Node\Scalar\String_;
+use PHPStan\Analyser\Scope;
+use PHPStan\Analyser\SpecifiedTypes;
+use PHPStan\Analyser\TypeSpecifier;
+use PHPStan\Analyser\TypeSpecifierAwareExtension;
+use PHPStan\Analyser\TypeSpecifierContext;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\Constant\ConstantBooleanType;
+use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\FunctionTypeSpecifyingExtension;
+
+class FunctionExistsFunctionTypeSpecifyingExtension implements FunctionTypeSpecifyingExtension, TypeSpecifierAwareExtension
+{
+
+	private TypeSpecifier $typeSpecifier;
+
+	public function isFunctionSupported(
+		FunctionReflection $functionReflection,
+		FuncCall $node,
+		TypeSpecifierContext $context
+	): bool
+	{
+		return $functionReflection->getName() === 'function_exists' && isset($node->getArgs()[0]) && $context->truthy();
+	}
+
+	public function specifyTypes(FunctionReflection $functionReflection, FuncCall $node, Scope $scope, TypeSpecifierContext $context): SpecifiedTypes
+	{
+		$argType = $scope->getType($node->getArgs()[0]->value);
+		if ($argType instanceof ConstantStringType) {
+			return $this->typeSpecifier->create(
+				new FuncCall(new FullyQualified('function_exists'), [
+					new Arg(new String_(ltrim($argType->getValue(), '\\'))),
+				]),
+				new ConstantBooleanType(true),
+				$context,
+				false,
+				$scope
+			);
+		}
+
+		return new SpecifiedTypes();
+	}
+
+	public function setTypeSpecifier(TypeSpecifier $typeSpecifier): void
+	{
+		$this->typeSpecifier = $typeSpecifier;
+	}
+
+}
diff --git a/tests/PHPStan/Rules/Functions/CallToNonExistentFunctionRuleTest.php b/tests/PHPStan/Rules/Functions/CallToNonExistentFunctionRuleTest.php
@@ -121,4 +121,40 @@ public function testCreateFunctionPhp7(): void
 		$this->analyse([__DIR__ . '/data/create_function.php'], []);
 	}
 
+	public function testBug3576(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-3576.php'], [
+			[
+				'Function bug3576 not found.',
+				14,
+				'Learn more at https://phpstan.org/user-guide/discovering-symbols',
+			],
+			[
+				'Function bug3576 not found.',
+				17,
+				'Learn more at https://phpstan.org/user-guide/discovering-symbols',
+			],
+			[
+				'Function bug3576 not found.',
+				26,
+				'Learn more at https://phpstan.org/user-guide/discovering-symbols',
+			],
+			[
+				'Function bug3576 not found.',
+				29,
+				'Learn more at https://phpstan.org/user-guide/discovering-symbols',
+			],
+			[
+				'Function bug3576 not found.',
+				38,
+				'Learn more at https://phpstan.org/user-guide/discovering-symbols',
+			],
+			[
+				'Function bug3576 not found.',
+				41,
+				'Learn more at https://phpstan.org/user-guide/discovering-symbols',
+			],
+		]);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Functions/data/bug-3576.php b/tests/PHPStan/Rules/Functions/data/bug-3576.php
@@ -0,0 +1,45 @@
+<?php
+
+namespace Bug3576;
+
+class Foo
+{
+
+	public function doFoo(): void
+	{
+		if (\function_exists('bug3576')) {
+			bug3576();
+			\bug3576();
+		} else {
+			bug3576();
+		}
+
+		bug3576();
+	}
+
+	public function doBar(): void
+	{
+		if (function_exists('bug3576')) {
+			bug3576();
+			\bug3576();
+		} else {
+			bug3576();
+		}
+
+		bug3576();
+	}
+
+	public function doBaz(): void
+	{
+		if (function_exists('\bug3576')) {
+			bug3576();
+			\bug3576();
+		} else {
+			bug3576();
+		}
+
+		bug3576();
+	}
+
+}
+