Fix pathinfo() return type for union type flags

Author: staabm

src/Type/Php/PathinfoFunctionDynamicReturnTypeExtension.php

@@ -54,12 +54,24 @@ public function getTypeFromFunctionCall(
 		}
 
 		$flagsType = $scope->getType($functionCall->getArgs()[1]->value);
-		if ($flagsType instanceof ConstantIntegerType) {
-			if ($flagsType->getValue() === $this->getConstant('PATHINFO_ALL')) {
-				return $arrayType;
+
+		$scalarValues = $flagsType->getConstantScalarValues();
+		if ($scalarValues !== []) {
+			$pathInfoAll = $this->getConstant('PATHINFO_ALL');
+			if ($pathInfoAll === null) {
+				return null;
+			}
+
+			$result = [];
+			foreach ($scalarValues as $scalarValue) {
+				if ($scalarValue === $pathInfoAll) {
+					$result[] = $arrayType;
+				} else {
+					$result[] = new StringType();
+				}
 			}
 
-			return new StringType();
+			return TypeCombinator::union(...$result);
 		}
 
 		return TypeCombinator::union($arrayType, new StringType());

tests/PHPStan/Analyser/nsrt/pathinfo.php

@@ -4,12 +4,23 @@
 
 use function PHPStan\Testing\assertType;
 
-function doFoo(string $s,  int $i) {
+/**
+ * @param PATHINFO_BASENAME|PATHINFO_EXTENSION $flag
+ */
+function doFoo(string $s, int $i, $flag) {
 	assertType('array{dirname?: string, basename: string, extension?: string, filename: string}|string', pathinfo($s,  $i));
 	assertType('array{dirname?: string, basename: string, extension?: string, filename: string}', pathinfo($s));
 
 	assertType('string', pathinfo($s, PATHINFO_DIRNAME));
 	assertType('string', pathinfo($s, PATHINFO_BASENAME));
 	assertType('string', pathinfo($s, PATHINFO_EXTENSION));
 	assertType('string', pathinfo($s, PATHINFO_FILENAME));
+
+	assertType('string', pathinfo($s, $flag));
+	if ($i === PATHINFO_ALL) {
+		assertType('array{dirname?: string, basename: string, extension?: string, filename: string}', pathinfo($s, $i));
+	}
+	if ($i === PATHINFO_ALL || $i === PATHINFO_DIRNAME) {
+		assertType('array{dirname?: string, basename: string, extension?: string, filename: string}|string', pathinfo($s, $i));
+	}
 }