[DeadCode] Add RemoveUnusedNonEmptyArrayBeforeForeachRector (#3066)

config/set/dead-code/dead-code.yaml

@@ -36,3 +36,4 @@ services:
     Rector\DeadCode\Rector\Assign\RemoveUnusedVariableAssignRector: null
     Rector\DeadCode\Rector\FunctionLike\RemoveDuplicatedIfReturnRector: null
     Rector\DeadCode\Rector\Function_\RemoveUnusedFunctionRector: null
+    Rector\DeadCode\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector: null

docs/AllRectorsOverview.md

@@ -1,4 +1,4 @@
-# All 468 Rectors Overview
+# All 469 Rectors Overview
 
 - [Projects](#projects)
 - [General](#general)
@@ -3083,6 +3083,32 @@ Remove unused function
 
 <br>
 
+### `RemoveUnusedNonEmptyArrayBeforeForeachRector`
+
+- class: [`Rector\DeadCode\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector`](/../master/rules/dead-code/src/Rector/If_/RemoveUnusedNonEmptyArrayBeforeForeachRector.php)
+- [test fixtures](/../master/rules/dead-code/tests/Rector/If_/RemoveUnusedNonEmptyArrayBeforeForeachRector/Fixture)
+
+Remove unused if check to non-empty array before foreach of the array
+
+```diff
+ class SomeClass
+ {
+     public function run()
+     {
+         $values = [];
+-        if ($values !== []) {
+-            foreach ($values as $value) {
+-                echo $value;
+-            }
++        foreach ($values as $value) {
++            echo $value;
+         }
+     }
+ }
+```
+
+<br>
+
 ### `RemoveUnusedParameterRector`
 
 - class: [`Rector\DeadCode\Rector\ClassMethod\RemoveUnusedParameterRector`](/../master/rules/dead-code/src/Rector/ClassMethod/RemoveUnusedParameterRector.php)

rules/dead-code/src/Rector/If_/RemoveUnusedNonEmptyArrayBeforeForeachRector.php

@@ -0,0 +1,135 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\DeadCode\Rector\If_;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\Array_;
+use PhpParser\Node\Expr\BinaryOp;
+use PhpParser\Node\Expr\BinaryOp\NotEqual;
+use PhpParser\Node\Expr\BinaryOp\NotIdentical;
+use PhpParser\Node\Stmt\Foreach_;
+use PhpParser\Node\Stmt\If_;
+use Rector\Core\PhpParser\Node\Manipulator\IfManipulator;
+use Rector\Core\Rector\AbstractRector;
+use Rector\Core\RectorDefinition\CodeSample;
+use Rector\Core\RectorDefinition\RectorDefinition;
+
+/**
+ * @see \Rector\DeadCode\Tests\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector\RemoveUnusedNonEmptyArrayBeforeForeachRectorTest
+ */
+final class RemoveUnusedNonEmptyArrayBeforeForeachRector extends AbstractRector
+{
+    /**
+     * @var IfManipulator
+     */
+    private $ifManipulator;
+
+    public function __construct(IfManipulator $ifManipulator)
+    {
+        $this->ifManipulator = $ifManipulator;
+    }
+
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Remove unused if check to non-empty array before foreach of the array', [
+            new CodeSample(
+                <<<'PHP'
+class SomeClass
+{
+    public function run()
+    {
+        $values = [];
+        if ($values !== []) {
+            foreach ($values as $value) {
+                echo $value;
+            }
+        }
+    }
+}
+PHP
+,
+                <<<'PHP'
+class SomeClass
+{
+    public function run()
+    {
+        $values = [];
+        foreach ($values as $value) {
+            echo $value;
+        }
+    }
+}
+PHP
+
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [If_::class];
+    }
+
+    /**
+     * @param If_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        if (! $this->ifManipulator->isIfWithOnlyForeach($node)) {
+            return null;
+        }
+
+        /** @var Foreach_ $foreach */
+        $foreach = $node->stmts[0];
+        $foreachExpr = $foreach->expr;
+
+        if (! $node->cond instanceof NotIdentical && ! $node->cond instanceof NotEqual) {
+            return null;
+        }
+
+        /** @var NotIdentical|NotEqual $notIdentical */
+        $notIdentical = $node->cond;
+
+        if (! $this->isMatching($notIdentical, $foreachExpr)) {
+            return null;
+        }
+
+        return $foreach;
+    }
+
+    private function isEmptyArray(Expr $expr): bool
+    {
+        if (! $expr instanceof Array_) {
+            return false;
+        }
+
+        return $expr->items === [];
+    }
+
+    private function isEmptyArrayAndForeachedVariable(Expr $leftExpr, Expr $rightExpr, Expr $foreachExpr): bool
+    {
+        if (! $this->isEmptyArray($leftExpr)) {
+            return false;
+        }
+
+        return $this->areNodesWithoutCommentsEqual($foreachExpr, $rightExpr);
+    }
+
+    /**
+     * @param NotIdentical|NotEqual $binaryOp
+     */
+    private function isMatching(BinaryOp $binaryOp, Expr $foreachExpr): bool
+    {
+        if ($this->isEmptyArrayAndForeachedVariable($binaryOp->left, $binaryOp->right, $foreachExpr)) {
+            return true;
+        }
+
+        return $this->isEmptyArrayAndForeachedVariable($binaryOp->right, $binaryOp->left, $foreachExpr);
+    }
+}

rules/dead-code/tests/Rector/If_/RemoveUnusedNonEmptyArrayBeforeForeachRector/Fixture/fixture.php.inc

@@ -0,0 +1,45 @@
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector\Fixture;
+
+class SomeClass
+{
+    public function run()
+    {
+        $values = [];
+        if ($values !== []) {
+            foreach ($values as $value) {
+                echo $value;
+            }
+        }
+
+        if ([] !== $values) {
+            foreach ($values as $value) {
+                echo $value;
+            }
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector\Fixture;
+
+class SomeClass
+{
+    public function run()
+    {
+        $values = [];
+        foreach ($values as $value) {
+            echo $value;
+        }
+
+        foreach ($values as $value) {
+            echo $value;
+        }
+    }
+}
+
+?>

rules/dead-code/tests/Rector/If_/RemoveUnusedNonEmptyArrayBeforeForeachRector/Fixture/not_equal.php.inc

@@ -0,0 +1,35 @@
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector\Fixture;
+
+class NotEqual
+{
+    public function run()
+    {
+        $values = [];
+        if ($values != []) {
+            foreach ($values as $value) {
+                echo $value;
+            }
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector\Fixture;
+
+class NotEqual
+{
+    public function run()
+    {
+        $values = [];
+        foreach ($values as $value) {
+            echo $value;
+        }
+    }
+}
+
+?>

rules/dead-code/tests/Rector/If_/RemoveUnusedNonEmptyArrayBeforeForeachRector/Fixture/skip_different_foreach.php.inc

@@ -0,0 +1,18 @@
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector\Fixture;
+
+class SkipDifferentForeach
+{
+    public function run()
+    {
+        $values = [];
+        $values2 = [];
+
+        if ($values != []) {
+            foreach ($values2 as $value) {
+                echo $value;
+            }
+        }
+    }
+}

rules/dead-code/tests/Rector/If_/RemoveUnusedNonEmptyArrayBeforeForeachRector/RemoveUnusedNonEmptyArrayBeforeForeachRectorTest.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\DeadCode\Tests\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector;
+
+use Iterator;
+use Rector\Core\Testing\PHPUnit\AbstractRectorTestCase;
+use Rector\DeadCode\Rector\If_\RemoveUnusedNonEmptyArrayBeforeForeachRector;
+
+final class RemoveUnusedNonEmptyArrayBeforeForeachRectorTest extends AbstractRectorTestCase
+{
+    /**
+     * @dataProvider provideData()
+     */
+    public function test(string $file): void
+    {
+        $this->doTestFile($file);
+    }
+
+    public function provideData(): Iterator
+    {
+        return $this->yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    protected function getRectorClass(): string
+    {
+        return RemoveUnusedNonEmptyArrayBeforeForeachRector::class;
+    }
+}

src/PhpParser/Node/Manipulator/IfManipulator.php

@@ -276,6 +276,19 @@ final class IfManipulator
         return $this->hasOnlyStmtOfType($node, Return_::class);
     }
 
+    public function isIfWithOnlyForeach(Node $node): bool
+    {
+        if (! $node instanceof If_) {
+            return false;
+        }
+
+        if (! $this->isIfWithoutElseAndElseIfs($node)) {
+            return false;
+        }
+
+        return $this->hasOnlyStmtOfType($node, Foreach_::class);
+    }
+
     private function matchComparedAndReturnedNode(NotIdentical $notIdentical, Return_ $returnNode): ?Expr
     {
         if ($this->betterStandardPrinter->areNodesEqual(