From fcc91091b0a4a3925566c508ce93ca35e42a65b8 Mon Sep 17 00:00:00 2001
From: Tomas Votruba <tomas.vot@gmail.com>
Date: Mon, 27 Oct 2025 21:18:10 +0100
Subject: [PATCH] [type-declaration] Add ReturnIteratorInDataProviderRector

---
 .../Fixture/skip_already_known.php.inc        |  21 +++
 .../Fixture/skip_non_data_provider.php.inc    |  18 +++
 .../Fixture/some_class.php.inc                |  47 +++++++
 ...ReturnIteratorInDataProviderRectorTest.php |  28 ++++
 .../config/configured_rule.php                |  10 ++
 .../ReturnIteratorInDataProviderRector.php    | 123 ++++++++++++++++++
 src/Config/Level/TypeDeclarationLevel.php     |   2 +
 7 files changed, 249 insertions(+)
 create mode 100644 rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/skip_already_known.php.inc
 create mode 100644 rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/skip_non_data_provider.php.inc
 create mode 100644 rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/some_class.php.inc
 create mode 100644 rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/ReturnIteratorInDataProviderRectorTest.php
 create mode 100644 rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/config/configured_rule.php
 create mode 100644 rules/CodeQuality/Rector/Class_/ReturnIteratorInDataProviderRector.php

diff --git a/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/skip_already_known.php.inc b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/skip_already_known.php.inc
new file mode 100644
index 00000000000..d838c90fc8e
--- /dev/null
+++ b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/skip_already_known.php.inc
@@ -0,0 +1,21 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnIteratorInDataProviderRector\Fixture;
+
+use PHPUnit\Framework\TestCase;
+
+final class SkipAlreadyKnown extends TestCase
+{
+    /**
+     * @dataProvider someDataProvider
+     */
+    public function testSomething()
+    {
+    }
+
+    public function someDataProvider(): \Generator
+    {
+        yield ['data1'];
+        yield ['data2'];
+    }
+}
diff --git a/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/skip_non_data_provider.php.inc b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/skip_non_data_provider.php.inc
new file mode 100644
index 00000000000..1fc83e17034
--- /dev/null
+++ b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/skip_non_data_provider.php.inc
@@ -0,0 +1,18 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnIteratorInDataProviderRector\Fixture;
+
+use PHPUnit\Framework\TestCase;
+
+final class SkipNonDataProvider extends TestCase
+{
+    public function testSomething()
+    {
+    }
+
+    public function someDataProvider()
+    {
+        yield ['data1'];
+        yield ['data2'];
+    }
+}
diff --git a/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/some_class.php.inc b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/some_class.php.inc
new file mode 100644
index 00000000000..515433923d0
--- /dev/null
+++ b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/Fixture/some_class.php.inc
@@ -0,0 +1,47 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnIteratorInDataProviderRector\Fixture;
+
+use PHPUnit\Framework\TestCase;
+
+final class SomeClass extends TestCase
+{
+    /**
+     * @dataProvider someDataProvider
+     */
+    public function testSomething()
+    {
+    }
+
+    public function someDataProvider()
+    {
+        yield ['data1'];
+        yield ['data2'];
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnIteratorInDataProviderRector\Fixture;
+
+use PHPUnit\Framework\TestCase;
+
+final class SomeClass extends TestCase
+{
+    /**
+     * @dataProvider someDataProvider
+     */
+    public function testSomething()
+    {
+    }
+
+    public function someDataProvider(): \Iterator
+    {
+        yield ['data1'];
+        yield ['data2'];
+    }
+}
+
+?>
diff --git a/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/ReturnIteratorInDataProviderRectorTest.php b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/ReturnIteratorInDataProviderRectorTest.php
new file mode 100644
index 00000000000..484cf523761
--- /dev/null
+++ b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/ReturnIteratorInDataProviderRectorTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\TypeDeclaration\Rector\Class_\ReturnIteratorInDataProviderRector;
+
+use Iterator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class ReturnIteratorInDataProviderRectorTest extends AbstractRectorTestCase
+{
+    #[DataProvider('provideData')]
+    public function test(string $filePath): void
+    {
+        $this->doTestFile($filePath);
+    }
+
+    public static function provideData(): Iterator
+    {
+        return self::yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule.php';
+    }
+}
diff --git a/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/config/configured_rule.php b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/config/configured_rule.php
new file mode 100644
index 00000000000..81ec5e6cac8
--- /dev/null
+++ b/rules-tests/TypeDeclaration/Rector/Class_/ReturnIteratorInDataProviderRector/config/configured_rule.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\CodeQuality\Rector\Class_\ReturnIteratorInDataProviderRector;
+use Rector\Config\RectorConfig;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->rule(ReturnIteratorInDataProviderRector::class);
+};
diff --git a/rules/CodeQuality/Rector/Class_/ReturnIteratorInDataProviderRector.php b/rules/CodeQuality/Rector/Class_/ReturnIteratorInDataProviderRector.php
new file mode 100644
index 00000000000..2ecba009a54
--- /dev/null
+++ b/rules/CodeQuality/Rector/Class_/ReturnIteratorInDataProviderRector.php
@@ -0,0 +1,123 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\CodeQuality\Rector\Class_;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\Yield_;
+use PhpParser\Node\Name\FullyQualified;
+use PhpParser\Node\Stmt\Class_;
+use PhpParser\Node\Stmt\ClassMethod;
+use Rector\PhpParser\Node\BetterNodeFinder;
+use Rector\PHPUnit\NodeAnalyzer\TestsNodeAnalyzer;
+use Rector\Rector\AbstractRector;
+use Rector\TypeDeclarationDocblocks\NodeFinder\DataProviderMethodsFinder;
+use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
+use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
+
+/**
+ * @see \Rector\Tests\TypeDeclaration\Rector\Class_\ReturnIteratorInDataProviderRector\ReturnIteratorInDataProviderRectorTest
+ */
+final class ReturnIteratorInDataProviderRector extends AbstractRector
+{
+    public function __construct(
+        private readonly TestsNodeAnalyzer $testsNodeAnalyzer,
+        private readonly DataProviderMethodsFinder $dataProviderMethodsFinder,
+        private readonly BetterNodeFinder $betterNodeFinder
+    ) {
+    }
+
+    public function getRuleDefinition(): RuleDefinition
+    {
+        return new RuleDefinition('Add Iterator type on known PHPUnit data providers', [
+            new CodeSample(
+                <<<'CODE_SAMPLE'
+use PHPUnit\Framework\TestCase;
+
+final class SomeTest extends TestCase
+{
+    /**
+     * @dataProvider provideData()
+     */
+    public function testSomething($value)
+    {
+    }
+
+    public function provideData()
+    {
+        yield [5];
+    }
+}
+CODE_SAMPLE
+                ,
+                <<<'CODE_SAMPLE'
+use PHPUnit\Framework\TestCase;
+
+final class SomeTest extends TestCase
+{
+    /**
+     * @dataProvider provideData()
+     */
+    public function testSomething($value)
+    {
+    }
+
+    public function provideData(): \Iterator
+    {
+        yield [5];
+    }
+}
+CODE_SAMPLE
+            ),
+        ]);
+    }
+
+    /**
+     * @return array<class-string<Node>>
+     */
+    public function getNodeTypes(): array
+    {
+        return [Class_::class];
+    }
+
+    /**
+     * @param Class_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        if (! $this->testsNodeAnalyzer->isInTestClass($node)) {
+            return null;
+        }
+
+        $dataProviderClassMethods = $this->dataProviderMethodsFinder->findDataProviderNodesInClass($node);
+
+        $hasChanged = false;
+
+        foreach ($dataProviderClassMethods as $dataProviderClassMethod) {
+            if ($dataProviderClassMethod->returnType instanceof Node) {
+                continue;
+            }
+
+            if (! $this->hasYields($dataProviderClassMethod)) {
+                continue;
+            }
+
+            $dataProviderClassMethod->returnType = new FullyQualified('Iterator');
+            $hasChanged = true;
+        }
+
+        if ($hasChanged) {
+            return $node;
+        }
+
+        return null;
+    }
+
+    private function hasYields(ClassMethod $classMethod): bool
+    {
+        $yields = $this->betterNodeFinder->findInstancesOfScoped((array) $classMethod->stmts, Yield_::class);
+
+        return $yields !== [];
+    }
+}
diff --git a/src/Config/Level/TypeDeclarationLevel.php b/src/Config/Level/TypeDeclarationLevel.php
index 86d9818b931..5a521ba7f7c 100644
--- a/src/Config/Level/TypeDeclarationLevel.php
+++ b/src/Config/Level/TypeDeclarationLevel.php
@@ -4,6 +4,7 @@
 
 namespace Rector\Config\Level;
 
+use Rector\CodeQuality\Rector\Class_\ReturnIteratorInDataProviderRector;
 use Rector\Contract\Rector\RectorInterface;
 use Rector\Symfony\CodeQuality\Rector\ClassMethod\ResponseReturnTypeControllerActionRector;
 use Rector\TypeDeclaration\Rector\ArrowFunction\AddArrowFunctionReturnTypeRector;
@@ -78,6 +79,7 @@ final class TypeDeclarationLevel
         AddClosureVoidReturnTypeWhereNoReturnRector::class,
         AddFunctionVoidReturnTypeWhereNoReturnRector::class,
         AddTestsVoidReturnTypeWhereNoReturnRector::class,
+        ReturnIteratorInDataProviderRector::class,
 
         ReturnTypeFromMockObjectRector::class,
         TypedPropertyFromCreateMockAssignRector::class,