[CodingStyle] Add ArrayPropertyDefaultValueRector

config/level/coding-style/coding-style.yaml

@@ -20,3 +20,4 @@ services:
     Rector\CodingStyle\Rector\FuncCall\ConsistentPregDelimiterRector: ~
     Rector\CodingStyle\Rector\Include_\FollowRequireByDirRector: ~
     Rector\CodingStyle\Rector\Catch_\CatchExceptionNameMatchingTypeRector: ~
+    Rector\CodingStyle\Rector\Property\ArrayPropertyDefaultValueRector: ~

packages/CodingStyle/src/Rector/Property/ArrayPropertyDefaultValueRector.php

@@ -0,0 +1,97 @@
+<?php declare(strict_types=1);
+
+namespace Rector\CodingStyle\Rector\Property;
+
+use PhpParser\Node;
+use PhpParser\Node\Stmt\PropertyProperty;
+use Rector\NodeTypeResolver\Node\AttributeKey;
+use Rector\NodeTypeResolver\PhpDoc\NodeAnalyzer\DocBlockManipulator;
+use Rector\Rector\AbstractRector;
+use Rector\RectorDefinition\CodeSample;
+use Rector\RectorDefinition\RectorDefinition;
+
+final class ArrayPropertyDefaultValueRector extends AbstractRector
+{
+    /**
+     * @var DocBlockManipulator
+     */
+    private $docBlockManipulator;
+
+    public function __construct(DocBlockManipulator $docBlockManipulator)
+    {
+        $this->docBlockManipulator = $docBlockManipulator;
+    }
+
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Array property should have default value, to prevent undefined array issues', [
+            new CodeSample(
+                <<<'CODE_SAMPLE'
+class SomeClass
+{
+    /**
+     * @var int[]
+     */
+    private $items;
+
+    public function run()
+    {
+        foreach ($items as $item) {
+        }
+    }
+}
+CODE_SAMPLE
+                ,
+                <<<'CODE_SAMPLE'
+class SomeClass
+{
+    /**
+     * @var int[]
+     */
+    private $items = [];
+
+    public function run()
+    {
+        foreach ($items as $item) {
+        }
+    }
+}
+CODE_SAMPLE
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [PropertyProperty::class];
+    }
+
+    /**
+     * @param PropertyProperty $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        if ($node->default) {
+            return null;
+        }
+
+        /** @var Node\Stmt\Property $parentNode */
+        $parentNode = $node->getAttribute(AttributeKey::PARENT_NODE);
+
+        $varTypeInfo = $this->docBlockManipulator->getVarTypeInfo($parentNode);
+        if ($varTypeInfo === null) {
+            return null;
+        }
+
+        if (! $varTypeInfo->isIterable()) {
+            return null;
+        }
+
+        $node->default = new Node\Expr\Array_();
+
+        return $node;
+    }
+}

packages/CodingStyle/tests/Rector/Property/ArrayPropertyDefaultValueRector/ArrayPropertyDefaultValueRectorTest.php

@@ -0,0 +1,23 @@
+<?php declare(strict_types=1);
+
+namespace Rector\CodingStyle\Tests\Rector\Property\ArrayPropertyDefaultValueRector;
+
+use Rector\CodingStyle\Rector\Property\ArrayPropertyDefaultValueRector;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class ArrayPropertyDefaultValueRectorTest extends AbstractRectorTestCase
+{
+    public function test(): void
+    {
+        $this->doTestFiles([
+            __DIR__ . '/Fixture/fixture.php.inc',
+            __DIR__ . '/Fixture/skip.php.inc',
+            __DIR__ . '/Fixture/static_property.php.inc',
+        ]);
+    }
+
+    protected function getRectorClass(): string
+    {
+        return ArrayPropertyDefaultValueRector::class;
+    }
+}

packages/CodingStyle/tests/Rector/Property/ArrayPropertyDefaultValueRector/Fixture/fixture.php.inc

@@ -0,0 +1,59 @@
+<?php
+
+namespace Rector\CodingStyle\Tests\Rector\Property\ArrayPropertyDefaultValueRector\Fixture;
+
+class SomeClass
+{
+    /**
+     * @var int[]
+     */
+    private $items;
+
+    /**
+     * @var array|SomeEntity[]
+     */
+    public $entities;
+
+    /**
+     * @var Bar[]|Foo[]
+     */
+    private $combined;
+
+    public function run()
+    {
+        foreach ($items as $item) {
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\CodingStyle\Tests\Rector\Property\ArrayPropertyDefaultValueRector\Fixture;
+
+class SomeClass
+{
+    /**
+     * @var int[]
+     */
+    private $items = [];
+
+    /**
+     * @var array|SomeEntity[]
+     */
+    public $entities = [];
+
+    /**
+     * @var Bar[]|Foo[]
+     */
+    private $combined = [];
+
+    public function run()
+    {
+        foreach ($items as $item) {
+        }
+    }
+}
+
+?>

packages/CodingStyle/tests/Rector/Property/ArrayPropertyDefaultValueRector/Fixture/skip.php.inc

@@ -0,0 +1,31 @@
+<?php
+
+namespace Rector\CodingStyle\Tests\Rector\Property\ArrayPropertyDefaultValueRector\Fixture;
+
+class Skip
+{
+    /**
+     * @var Collection|Foo[]
+     */
+    private $foo;
+
+    /**
+     * @var ArrayObject|int[]
+     */
+    public $property;
+
+    /**
+     * @var SplObjectStorage|int[]
+     */
+    public $anotherProperty;
+
+    /**
+     * @var \ArrayObject|int[]
+     */
+    public $propertyWithPreslash;
+
+    /**
+     * @var \SplObjectStorage|int[]
+     */
+    public $anotherPropertyWithPreslash;
+}

packages/CodingStyle/tests/Rector/Property/ArrayPropertyDefaultValueRector/Fixture/static_property.php.inc

@@ -0,0 +1,29 @@
+<?php
+
+namespace Rector\CodingStyle\Tests\Rector\Property\ArrayPropertyDefaultValueRector\Fixture;
+
+class StaticProperty
+{
+    /** @var int[] */
+    public static $property;
+
+    /** @var int[][] */
+    public $doubleArray;
+}
+
+?>
+-----
+<?php
+
+namespace Rector\CodingStyle\Tests\Rector\Property\ArrayPropertyDefaultValueRector\Fixture;
+
+class StaticProperty
+{
+    /** @var int[] */
+    public static $property = [];
+
+    /** @var int[][] */
+    public $doubleArray = [];
+}
+
+?>

packages/NodeTypeResolver/src/Php/VarTypeInfo.php

@@ -48,4 +48,19 @@ final class VarTypeInfo extends AbstractTypeInfo
     {
         return $this->fqnTypes[0] ?? null;
     }
+
+    public function isIterable(): bool
+    {
+        if ($this->types === []) {
+            return false;
+        }
+
+        foreach ($this->types as $type) {
+            if ($type !== 'array') {
+                return false;
+            }
+        }
+
+        return true;
+    }
 }