[TypeDeclaration] Add false and true in union support on ReturnUnionT…

…ypeRector (#5355)

* [TypeDeclaration] Add false and true in union on ReturnUnionTypeRector

* Fix

* failing fixture

* fixing true and false exists in union

* [ci-review] Rector Rectify

* fix

* fixture fix

* fix namespace

* reduce complexity

* fix phpstan

---------

Co-authored-by: GitHub Action <actions@github.com>

phpstan.neon

@@ -132,6 +132,7 @@ parameters:
                 - src/PhpDocParser/PhpDocParser/PhpDocNodeTraverser.php
                 - rules/Php70/EregToPcreTransformer.php
                 - src/BetterPhpDocParser/PhpDocManipulator/PhpDocClassRenamer.php
+                - src/NodeTypeResolver/PHPStan/Type/TypeFactory.php
 
         # known types
         - '#Parameter (.*?) expects PhpParser\\Node, PhpParser\\Node\|null given#'

rules-tests/TypeDeclaration/Rector/ClassMethod/ReturnUnionTypeRector/Fixture/multi_scalar.php.inc

@@ -22,7 +22,7 @@ namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector\
 
 final class MultiScalar
 {
-    public function run($value): bool|string
+    public function run($value): false|string
     {
         if ($value) {
             return false;

rules-tests/TypeDeclaration/Rector/ClassMethod/ReturnUnionTypeRector/Fixture/true_in_union_become_bool.php.inc

@@ -0,0 +1,41 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector\Fixture;
+
+/**
+ * true|othertype cannot work on <=php 8.1, ref https://3v4l.org/UJqXT
+ */
+final class TrueInUnionBecomeBool
+{
+    public function run($value)
+    {
+        if ($value) {
+            return true;
+        }
+
+        return substr('warning', 1);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector\Fixture;
+
+/**
+ * true|othertype cannot work on <=php 8.1, ref https://3v4l.org/UJqXT
+ */
+final class TrueInUnionBecomeBool
+{
+    public function run($value): bool|string
+    {
+        if ($value) {
+            return true;
+        }
+
+        return substr('warning', 1);
+    }
+}
+
+?>

rules-tests/TypeDeclaration/Rector/ClassMethod/ReturnUnionTypeRector/FixtureTrueInUnion/true_false_in_union.php.inc

@@ -0,0 +1,43 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector\FixtureTrueInUnion;
+
+final class TrueFalseInUnion
+{
+    public function run($value)
+    {
+        if ($value) {
+            return true;
+        }
+
+        if (rand(0, 1)) {
+            return false;
+        }
+
+        return substr('warning', 1);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector\FixtureTrueInUnion;
+
+final class TrueFalseInUnion
+{
+    public function run($value): bool|string
+    {
+        if ($value) {
+            return true;
+        }
+
+        if (rand(0, 1)) {
+            return false;
+        }
+
+        return substr('warning', 1);
+    }
+}
+
+?>

rules-tests/TypeDeclaration/Rector/ClassMethod/ReturnUnionTypeRector/FixtureTrueInUnion/true_in_union.php.inc

@@ -0,0 +1,41 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector\FixtureTrueInUnion;
+
+/**
+ * true|othertype work on >= php 8.2, ref https://3v4l.org/UJqXT
+ */
+final class TrueInUnion
+{
+    public function run($value)
+    {
+        if ($value) {
+            return true;
+        }
+
+        return substr('warning', 1);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector\FixtureTrueInUnion;
+
+/**
+ * true|othertype work on >= php 8.2, ref https://3v4l.org/UJqXT
+ */
+final class TrueInUnion
+{
+    public function run($value): true|string
+    {
+        if ($value) {
+            return true;
+        }
+
+        return substr('warning', 1);
+    }
+}
+
+?>

rules-tests/TypeDeclaration/Rector/ClassMethod/ReturnUnionTypeRector/TrueInUnionTest.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector;
+
+use Iterator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class TrueInUnionTest extends AbstractRectorTestCase
+{
+    #[DataProvider('provideData')]
+    public function test(string $filePath): void
+    {
+        $this->doTestFile($filePath);
+    }
+
+    public static function provideData(): Iterator
+    {
+        return self::yieldFilesFromDirectory(__DIR__ . '/FixtureTrueInUnion');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule_true_in_union.php';
+    }
+}

rules-tests/TypeDeclaration/Rector/ClassMethod/ReturnUnionTypeRector/config/configured_rule.php

@@ -3,8 +3,10 @@
 declare(strict_types=1);
 
 use Rector\Config\RectorConfig;
+use Rector\ValueObject\PhpVersionFeature;
 use Rector\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector;
 
 return static function (RectorConfig $rectorConfig): void {
     $rectorConfig->rule(ReturnUnionTypeRector::class);
+    $rectorConfig->phpVersion(PhpVersionFeature::UNION_TYPES);
 };

rules-tests/TypeDeclaration/Rector/ClassMethod/ReturnUnionTypeRector/config/configured_rule_true_in_union.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+use Rector\ValueObject\PhpVersionFeature;
+use Rector\TypeDeclaration\Rector\ClassMethod\ReturnUnionTypeRector;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->rule(ReturnUnionTypeRector::class);
+    $rectorConfig->phpVersion(PhpVersionFeature::NULL_FALSE_TRUE_STANDALONE_TYPE);
+};

rules/TypeDeclaration/TypeInferer/ReturnTypeInferer/ReturnedNodesReturnTypeInfererTypeInferer.php

@@ -66,7 +66,7 @@ public function inferFunctionLike(FunctionLike $functionLike): Type
             $types[] = new VoidType();
         }
 
-        return $this->typeFactory->createMixedPassedOrUnionType($types);
+        return $this->typeFactory->createMixedPassedOrUnionTypeAndKeepConstant($types);
     }
 
     /**

src/NodeTypeResolver/PHPStan/Type/TypeFactory.php

@@ -62,11 +62,11 @@ public function uniquateTypes(array $types, bool $keepConstant = false): array
         $uniqueTypes = [];
         $totalTypes = count($types);
 
+        $hasFalse = false;
+        $hasTrue = false;
         foreach ($types as $type) {
-            if ($totalTypes > 1 && $type instanceof ObjectWithoutClassTypeWithParentTypes) {
-                $parents = $type->getParentTypes();
-                $type = new ObjectType($parents[0]->getClassName());
-            }
+            $type = $this->normalizeObjectType($totalTypes, $type);
+            $type = $this->normalizeBooleanType($hasFalse, $hasTrue, $type);
 
             $removedConstantType = $this->removeValueFromConstantType($type);
             $removedConstantTypeHash = $this->typeHasher->createTypeHash($removedConstantType);
@@ -92,6 +92,35 @@ public function uniquateTypes(array $types, bool $keepConstant = false): array
         return array_values($uniqueTypes);
     }
 
+    private function normalizeObjectType(int $totalTypes, Type $type): Type
+    {
+        if ($totalTypes > 1 && $type instanceof ObjectWithoutClassTypeWithParentTypes) {
+            $parents = $type->getParentTypes();
+            return new ObjectType($parents[0]->getClassName());
+        }
+
+        return $type;
+    }
+
+    private function normalizeBooleanType(bool &$hasFalse, bool &$hasTrue, Type $type): Type
+    {
+        if ($type instanceof ConstantBooleanType) {
+            if ($type->getValue()) {
+                $hasTrue = true;
+            }
+
+            if ($type->getValue() === false) {
+                $hasFalse = true;
+            }
+        }
+
+        if ($hasFalse && $hasTrue && $type instanceof ConstantBooleanType) {
+            return new BooleanType();
+        }
+
+        return $type;
+    }
+
     /**
      * @param Type[] $types
      * @return Type[]

src/NodeTypeResolver/PHPStan/TypeHasher.php

@@ -46,7 +46,7 @@ public function createTypeHash(Type $type): string
         }
 
         if ($type instanceof ConstantType) {
-            return $type::class . $type->getValue();
+            return $type::class;
         }
 
         if ($type instanceof UnionType) {