[TypeDeclaration] Add ReturnTypeFromStrictTernaryRector (#3318)

build/target-repository/docs/rector_rules_overview.md

@@ -1,4 +1,4 @@
-# 421 Rules Overview
+# 422 Rules Overview
 
 <br>
 
@@ -64,7 +64,7 @@
 
 - [Transform](#transform) (34)
 
-- [TypeDeclaration](#typedeclaration) (40)
+- [TypeDeclaration](#typedeclaration) (41)
 
 - [Visibility](#visibility) (3)
 
@@ -9689,6 +9689,25 @@ Add strict return array type based on created empty array and returned
 
 <br>
 
+### ReturnTypeFromStrictTernaryRector
+
+Add method return type based on strict ternary values
+
+- class: [`Rector\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector`](../rules/TypeDeclaration/Rector/Class_/ReturnTypeFromStrictTernaryRector.php)
+
+```diff
+ final class SomeClass
+ {
+-    public function getValue($number)
++    public function getValue($number): int
+     {
+         return $number ? 100 : 500;
+     }
+ }
+```
+
+<br>
+
 ### ReturnTypeFromStrictTypedCallRector
 
 Add return type from strict return type of call

config/set/type-declaration.php

@@ -6,6 +6,7 @@
 use Rector\Config\RectorConfig;
 use Rector\TypeDeclaration\Rector\ArrowFunction\AddArrowFunctionReturnTypeRector;
 use Rector\TypeDeclaration\Rector\Class_\PropertyTypeFromStrictSetterGetterRector;
+use Rector\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector;
 use Rector\TypeDeclaration\Rector\ClassMethod\AddMethodCallBasedStrictParamTypeRector;
 use Rector\TypeDeclaration\Rector\ClassMethod\AddParamTypeBasedOnPHPUnitDataProviderRector;
 use Rector\TypeDeclaration\Rector\ClassMethod\AddParamTypeFromPropertyTypeRector;
@@ -70,5 +71,6 @@
         ReturnNeverTypeRector::class,
         EmptyOnNullableObjectToInstanceOfRector::class,
         PropertyTypeFromStrictSetterGetterRector::class,
+        ReturnTypeFromStrictTernaryRector::class,
     ]);
 };

rules-tests/TypeDeclaration/Rector/Class_/ReturnTypeFromStrictTernaryRector/Fixture/local_constants.php.inc

@@ -0,0 +1,33 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector\Fixture;
+
+final class LocalConstants
+{
+    const FIRST = 'hey';
+    const SECOND = 'hou';
+
+    public function getValue($number)
+    {
+        return $number ? self::FIRST : self::SECOND;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector\Fixture;
+
+final class LocalConstants
+{
+    const FIRST = 'hey';
+    const SECOND = 'hou';
+
+    public function getValue($number): string
+    {
+        return $number ? self::FIRST : self::SECOND;
+    }
+}
+
+?>

rules-tests/TypeDeclaration/Rector/Class_/ReturnTypeFromStrictTernaryRector/Fixture/skip_dynamic_scalar.php.inc

@@ -0,0 +1,11 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector\Fixture;
+
+final class SkipDynamicScalar
+{
+    public function getValue($number)
+    {
+        return $number ? 100 : (500 + $number);
+    }
+}

rules-tests/TypeDeclaration/Rector/Class_/ReturnTypeFromStrictTernaryRector/Fixture/some_class.php.inc

@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector\Fixture;
+
+final class SomeClass
+{
+    public function getValue($number)
+    {
+        return $number ? 100 : 500;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector\Fixture;
+
+final class SomeClass
+{
+    public function getValue($number): int
+    {
+        return $number ? 100 : 500;
+    }
+}
+
+?>

rules-tests/TypeDeclaration/Rector/Class_/ReturnTypeFromStrictTernaryRector/ReturnTypeFromStrictTernaryRectorTest.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector;
+
+use Iterator;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class ReturnTypeFromStrictTernaryRectorTest extends AbstractRectorTestCase
+{
+    /**
+     * @dataProvider provideData()
+     */
+    public function test(string $filePath): void
+    {
+        $this->doTestFile($filePath);
+    }
+
+    /**
+     * @return Iterator<string>
+     */
+    public function provideData(): Iterator
+    {
+        return $this->yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule.php';
+    }
+}

rules-tests/TypeDeclaration/Rector/Class_/ReturnTypeFromStrictTernaryRector/config/configured_rule.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+
+use Rector\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->rule(ReturnTypeFromStrictTernaryRector::class);
+};

rules/TypeDeclaration/Rector/Class_/ReturnTypeFromStrictTernaryRector.php

@@ -0,0 +1,186 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\TypeDeclaration\Rector\Class_;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\ClassConstFetch;
+use PhpParser\Node\Expr\ConstFetch;
+use PhpParser\Node\Expr\Ternary;
+use PhpParser\Node\Scalar;
+use PhpParser\Node\Stmt\Class_;
+use PhpParser\Node\Stmt\Return_;
+use PHPStan\Type\ConstantType;
+use PHPStan\Type\GeneralizePrecision;
+use PHPStan\Type\Type;
+use Rector\Core\Rector\AbstractRector;
+use Rector\Core\ValueObject\PhpVersionFeature;
+use Rector\PHPStanStaticTypeMapper\Enum\TypeKind;
+use Rector\TypeDeclaration\ValueObject\TernaryIfElseTypes;
+use Rector\VendorLocker\ParentClassMethodTypeOverrideGuard;
+use Rector\VersionBonding\Contract\MinPhpVersionInterface;
+use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
+use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
+
+/**
+ * @see \Rector\Tests\TypeDeclaration\Rector\Class_\ReturnTypeFromStrictTernaryRector\ReturnTypeFromStrictTernaryRectorTest
+ */
+final class ReturnTypeFromStrictTernaryRector extends AbstractRector implements MinPhpVersionInterface
+{
+    public function __construct(
+        private readonly ParentClassMethodTypeOverrideGuard $parentClassMethodTypeOverrideGuard
+    ) {
+    }
+
+    public function getRuleDefinition(): RuleDefinition
+    {
+        return new RuleDefinition('Add method return type based on strict ternary values', [
+            new CodeSample(
+                <<<'CODE_SAMPLE'
+final class SomeClass
+{
+    public function getValue($number)
+    {
+        return $number ? 100 : 500;
+    }
+}
+CODE_SAMPLE
+
+                ,
+                <<<'CODE_SAMPLE'
+final class SomeClass
+{
+    public function getValue($number): int
+    {
+        return $number ? 100 : 500;
+    }
+}
+CODE_SAMPLE
+            ),
+        ]);
+    }
+
+    /**
+     * @return array<class-string<Node>>
+     */
+    public function getNodeTypes(): array
+    {
+        return [Class_::class];
+    }
+
+    /**
+     * @param Class_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        $hasChanged = false;
+
+        foreach ($node->getMethods() as $classMethod) {
+            if ($classMethod->returnType instanceof Node) {
+                continue;
+            }
+
+            $onlyStmt = $classMethod->stmts[0] ?? null;
+            if (! $onlyStmt instanceof Return_) {
+                continue;
+            }
+
+            if (! $onlyStmt->expr instanceof Ternary) {
+                continue;
+            }
+
+            $ternary = $onlyStmt->expr;
+
+            // has scalar in if/else of ternary
+            $ternaryIfElseTypes = $this->matchScalarTernaryIfElseTypes($ternary);
+            if (! $ternaryIfElseTypes instanceof TernaryIfElseTypes) {
+                continue;
+            }
+
+            $ifType = $ternaryIfElseTypes->getFirstType();
+            $elseType = $ternaryIfElseTypes->getSecondType();
+
+            if (! $this->areTypesEqual($ifType, $elseType)) {
+                continue;
+            }
+
+            $returnTypeNode = $this->staticTypeMapper->mapPHPStanTypeToPhpParserNode($ifType, TypeKind::RETURN);
+
+            if ($this->parentClassMethodTypeOverrideGuard->shouldSkipReturnTypeChange($classMethod, $ifType)) {
+                continue;
+            }
+
+            if (! $returnTypeNode instanceof Node) {
+                continue;
+            }
+
+            $classMethod->returnType = $returnTypeNode;
+            $hasChanged = true;
+        }
+
+        if ($hasChanged) {
+            return $node;
+        }
+
+        return null;
+    }
+
+    public function provideMinPhpVersion(): int
+    {
+        return PhpVersionFeature::SCALAR_TYPES;
+    }
+
+    private function isAlwaysScalarExpr(?Expr $expr): bool
+    {
+        // check if Scalar node
+        if ($expr instanceof Scalar) {
+            return true;
+        }
+
+        // check if constant
+        if ($expr instanceof ConstFetch) {
+            return true;
+        }
+
+        // check if class constant
+        return $expr instanceof ClassConstFetch;
+    }
+
+    private function areTypesEqual(Type $firstType, Type $secondType): bool
+    {
+        // this is needed to make comparison tolerant to constant values, e.g. 5 and 10 are same only then
+        if ($firstType instanceof ConstantType) {
+            $firstType = $firstType->generalize(GeneralizePrecision::lessSpecific());
+        }
+
+        if ($secondType instanceof ConstantType) {
+            $secondType = $secondType->generalize(GeneralizePrecision::lessSpecific());
+        }
+
+        return $firstType->equals($secondType);
+    }
+
+    private function matchScalarTernaryIfElseTypes(Ternary $ternary): ?TernaryIfElseTypes
+    {
+        if (! $this->isAlwaysScalarExpr($ternary->if)) {
+            return null;
+        }
+
+        if (! $this->isAlwaysScalarExpr($ternary->else)) {
+            return null;
+        }
+
+        /** @var Node\Expr $if */
+        $if = $ternary->if;
+
+        /** @var Node\Expr $else */
+        $else = $ternary->else;
+
+        $ifType = $this->staticTypeMapper->mapPhpParserNodePHPStanType($if);
+        $elseType = $this->staticTypeMapper->mapPhpParserNodePHPStanType($else);
+
+        return new TernaryIfElseTypes($ifType, $elseType);
+    }
+}

rules/TypeDeclaration/ValueObject/TernaryIfElseTypes.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\TypeDeclaration\ValueObject;
+
+use PHPStan\Type\Type;
+
+final class TernaryIfElseTypes
+{
+    public function __construct(
+        private readonly Type $firstType,
+        private readonly Type $secondType,
+    ) {
+    }
+
+    public function getFirstType(): Type
+    {
+        return $this->firstType;
+    }
+
+    public function getSecondType(): Type
+    {
+        return $this->secondType;
+    }
+}