PHP does not cache is_dir() and similar function values for nonexistent files

ondrejmirtes · ondrejmirtes · commit 1eaef0463d23 · 2021-04-23T22:16:44.000+02:00
diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
@@ -3477,6 +3477,17 @@ public function specifyExpressionType(Expr $expr, Type $type, ?Type $nativeType
 			}
 		}
 
+		if ($expr instanceof FuncCall && $expr->name instanceof Name && $type instanceof ConstantBooleanType && !$type->getValue()) {
+			$functionName = $this->reflectionProvider->resolveFunctionName($expr->name, $this);
+			if ($functionName !== null && in_array(strtolower($functionName), [
+				'is_dir',
+				'is_file',
+				'file_exists',
+			], true)) {
+				return $this;
+			}
+		}
+
 		return $scope->addMoreSpecificTypes([
 			$exprString => $type,
 		]);
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -388,6 +388,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4879.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4820.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4822.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4816.php');
 	}
 
 	/**
diff --git a/tests/PHPStan/Analyser/data/bug-4816.php b/tests/PHPStan/Analyser/data/bug-4816.php
@@ -0,0 +1,47 @@
+<?php
+
+namespace Bug4816;
+
+use function PHPStan\Testing\assertType;
+
+function (): void {
+	if (is_dir('foo')) {
+		assertType('true', is_dir('foo'));
+		assertType('bool', is_dir('bar'));
+
+		clearstatcache();
+
+		assertType('bool', is_dir('foo'));
+		assertType('bool', is_dir('bar'));
+	}
+};
+
+function (): void {
+	if (!is_dir('foo')) {
+		assertType('bool', is_dir('foo'));
+		assertType('bool', is_dir('bar'));
+	}
+};
+
+function (): void {
+	if (!is_dir('foo')) {
+		return;
+	}
+
+	assertType('true', is_dir('foo'));
+	assertType('bool', is_dir('bar'));
+
+	clearstatcache();
+
+	assertType('bool', is_dir('foo'));
+	assertType('bool', is_dir('bar'));
+};
+
+function (): void {
+	if (is_dir('foo')) {
+		return;
+	}
+
+	assertType('bool', is_dir('foo'));
+	assertType('bool', is_dir('bar'));
+};

Original file line number	Diff line number	Diff line change
`@@ -388,6 +388,7 @@ public function dataFileAsserts(): iterable`
`388`	`388`	`yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4879.php');`
`389`	`389`	`yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4820.php');`
`390`	`390`	`yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4822.php');`
	`391`	`+ yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4816.php');`
`391`	`392`	`}`
`392`	`393`
`393`	`394`	`/**`