[code-quality] Add NewArrayItemConcatAssignToAssignRector (#8045)

Author: TomasVotruba

rules-tests/CodeQuality/Rector/AssignOp/NewArrayItemConcatAssignToAssignRector/Fixture/new_array_item.php.inc

@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\AssignOp\NewArrayItemConcatAssignToAssignRector\Fixture;
+
+class NewArrayItem
+{
+    public function run($return_data, $type, $name)
+    {
+        $return_data[$type][] .= $name;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\AssignOp\NewArrayItemConcatAssignToAssignRector\Fixture;
+
+class NewArrayItem
+{
+    public function run($return_data, $type, $name)
+    {
+        $return_data[$type][] = $name;
+    }
+}
+
+?>

rules-tests/CodeQuality/Rector/AssignOp/NewArrayItemConcatAssignToAssignRector/Fixture/skip_existing_key.php.inc

@@ -0,0 +1,11 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\AssignOp\NewArrayItemConcatAssignToAssignRector\Fixture;
+
+class SkipExistingKey
+{
+    public function run($return_data, $type, $name)
+    {
+        $return_data[$type] .= $name;
+    }
+}

rules-tests/CodeQuality/Rector/AssignOp/NewArrayItemConcatAssignToAssignRector/NewArrayItemConcatAssignToAssignRectorTest.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\CodeQuality\Rector\AssignOp\NewArrayItemConcatAssignToAssignRector;
+
+use Iterator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class NewArrayItemConcatAssignToAssignRectorTest 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';
+    }
+}

rules-tests/CodeQuality/Rector/AssignOp/NewArrayItemConcatAssignToAssignRector/config/configured_rule.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\CodeQuality\Rector\AssignOp\NewArrayItemConcatAssignToAssignRector;
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withRules([NewArrayItemConcatAssignToAssignRector::class]);

rules/CodeQuality/Rector/AssignOp/NewArrayItemConcatAssignToAssignRector.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\CodeQuality\Rector\AssignOp;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\ArrayDimFetch;
+use PhpParser\Node\Expr\Assign;
+use PhpParser\Node\Expr\AssignOp\Concat;
+use Rector\Rector\AbstractRector;
+use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
+use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
+
+/**
+ * @see \Rector\Tests\CodeQuality\Rector\AssignOp\NewArrayItemConcatAssignToAssignRector\NewArrayItemConcatAssignToAssignRectorTest
+ */
+final class NewArrayItemConcatAssignToAssignRector extends AbstractRector
+{
+    public function getRuleDefinition(): RuleDefinition
+    {
+        return new RuleDefinition(
+            'Change concat assign on a new array item to plain assign, as the new item is always null',
+            [
+                new CodeSample(
+                    <<<'CODE_SAMPLE'
+$values[] .= $name;
+CODE_SAMPLE
+                    ,
+                    <<<'CODE_SAMPLE'
+$values[] = $name;
+CODE_SAMPLE
+                ),
+            ]
+        );
+    }
+
+    public function getNodeTypes(): array
+    {
+        return [Concat::class];
+    }
+
+    /**
+     * @param Concat $node
+     */
+    public function refactor(Node $node): ?Assign
+    {
+        if (! $node->var instanceof ArrayDimFetch) {
+            return null;
+        }
+
+        if ($node->var->dim instanceof Node) {
+            return null;
+        }
+
+        return new Assign($node->var, $node->expr);
+    }
+}

src/Config/Level/CodeQualityLevel.php

@@ -5,6 +5,7 @@
 namespace Rector\Config\Level;
 
 use Rector\CodeQuality\Rector\Assign\CombinedAssignRector;
+use Rector\CodeQuality\Rector\AssignOp\NewArrayItemConcatAssignToAssignRector;
 use Rector\CodeQuality\Rector\Attribute\SortAttributeNamedArgsRector;
 use Rector\CodeQuality\Rector\BooleanAnd\RemoveUselessIsObjectCheckRector;
 use Rector\CodeQuality\Rector\BooleanAnd\RepeatedAndNotEqualToNotInArrayRector;
@@ -109,6 +110,7 @@ final class CodeQualityLevel
      */
     public const array RULES = [
         CombinedAssignRector::class,
+        NewArrayItemConcatAssignToAssignRector::class,
         SimplifyEmptyArrayCheckRector::class,
         ReplaceMultipleBooleanNotRector::class,
         ReplaceConstantBooleanNotRector::class,