[DeadCode] Do not remove variable that is re-assigned

ecs.yaml

@@ -56,6 +56,8 @@ parameters:
 
     skip:
         Symplify\CodingStandard\Sniffs\Architecture\DuplicatedClassShortNameSniff: ~
+        # skip temporary due to missing "import" feature in PhpStorm
+        SlevomatCodingStandard\Sniffs\Namespaces\ReferenceUsedNamesOnlySniff.PartialUse: ~
 
         # run manually from time to time - performance demanding + not to bother user with it
         Symplify\CodingStandard\Fixer\Order\PropertyOrderByComplexityFixer: ~

packages/DeadCode/src/Rector/Assign/RemoveDoubleAssignRector.php

@@ -77,9 +77,37 @@ CODE_SAMPLE
             return null;
         }
 
+        if ($this->shouldSkipDueToForeachOverride($node, $previousExpression)) {
+            return null;
+        }
+
         // no calls on right, could hide e.g. array_pop()|array_shift()
         $this->removeNode($node);
 
         return $node;
     }
+
+    private function shouldSkipDueToForeachOverride(Assign $assign, Node $node): bool
+    {
+        // is nested in a foreach and the previous expression is not?
+        $nodePreviousForeach = $this->betterNodeFinder->findFirstParentInstanceOf($assign, Node\Stmt\Foreach_::class);
+
+        $previousExpressionPreviousForeach = $this->betterNodeFinder->findFirstParentInstanceOf(
+            $node,
+            Node\Stmt\Foreach_::class
+        );
+
+        if ($nodePreviousForeach !== $previousExpressionPreviousForeach) {
+            if ($nodePreviousForeach instanceof Node\Stmt\Foreach_ && $assign->var instanceof Variable) {
+                // is value changed inside the foreach?
+
+                $variableAssigns = $this->betterNodeFinder->findAssignsOfVariable($nodePreviousForeach, $assign->var);
+
+                // there is probably value override
+                return count($variableAssigns) >= 2;
+            }
+        }
+
+        return false;
+    }
 }

packages/DeadCode/tests/Rector/Assign/RemoveDoubleAssignRector/Fixture/keep_array_reset.php.inc

@@ -0,0 +1,25 @@
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\Assign\RemoveDoubleAssignRector\Fixture;
+
+class KeepArrayReset
+{
+    public function create()
+    {
+        $values = [];
+        $unusedParameters = [];
+
+        foreach ($values as $param) {
+            if (true) {
+                // reset
+                $unusedParameters = [];
+
+                continue;
+            }
+
+            $unusedParameters[] = $param;
+        }
+
+        return $unusedParameters;
+    }
+}

packages/DeadCode/tests/Rector/Assign/RemoveDoubleAssignRector/RemoveDoubleAssignRectorTest.php

@@ -14,6 +14,7 @@ final class RemoveDoubleAssignRectorTest extends AbstractRectorTestCase
             __DIR__ . '/Fixture/calls.php.inc',
             __DIR__ . '/Fixture/keep_dim_assign.php.inc',
             __DIR__ . '/Fixture/property_assign.php.inc',
+            __DIR__ . '/Fixture/keep_array_reset.php.inc',
         ]);
     }
 

src/PhpParser/Node/BetterNodeFinder.php

@@ -7,6 +7,7 @@ use PhpParser\Node\Stmt;
 use PhpParser\Node\Stmt\Expression;
 use PhpParser\NodeFinder;
 use Rector\NodeTypeResolver\Node\Attribute;
+use Rector\PhpParser\Printer\BetterStandardPrinter;
 
 final class BetterNodeFinder
 {
@@ -15,9 +16,31 @@ final class BetterNodeFinder
      */
     private $nodeFinder;
 
-    public function __construct(NodeFinder $nodeFinder)
+    /**
+     * @var BetterStandardPrinter
+     */
+    private $betterStandardPrinter;
+
+    public function __construct(NodeFinder $nodeFinder, BetterStandardPrinter $betterStandardPrinter)
     {
         $this->nodeFinder = $nodeFinder;
+        $this->betterStandardPrinter = $betterStandardPrinter;
+    }
+
+    public function findFirstParentInstanceOf(Node $node, string $type): ?Node
+    {
+        /** @var Node|null $parentNode */
+        $parentNode = $node->getAttribute(Attribute::PARENT_NODE);
+        do {
+            if ($parentNode instanceof $type) {
+                return $parentNode;
+            }
+            if ($parentNode === null) {
+                return null;
+            }
+        } while ($parentNode = $parentNode->getAttribute(Attribute::PARENT_NODE));
+
+        return null;
     }
 
     public function findFirstAncestorInstanceOf(Node $node, string $type): ?Node
@@ -102,4 +125,24 @@ final class BetterNodeFinder
 
         return $this->findFirstPrevious($previousExpression, $filter);
     }
+
+    /**
+     * @return Node\Expr\Assign[]
+     */
+    public function findAssignsOfVariable(Node $node, Node\Expr\Variable $variable): array
+    {
+        $assignNodes = $this->findInstanceOf($node, Node\Expr\Assign::class);
+
+        return array_filter($assignNodes, function (Node\Expr\Assign $assign) use ($variable) {
+            if ($this->betterStandardPrinter->areNodesEqual($assign->var, $variable)) {
+                return true;
+            }
+
+            if ($assign->var instanceof Node\Expr\ArrayDimFetch) {
+                return $this->betterStandardPrinter->areNodesEqual($assign->var->var, $variable);
+            }
+
+            return false;
+        });
+    }
 }

tests/PhpParser/Node/BetterNodeFinder/BetterNodeFinderTest.php

@@ -7,14 +7,14 @@ use PhpParser\Node\Expr\Array_;
 use PhpParser\Node\Expr\Variable;
 use PhpParser\Node\Stmt\Class_;
 use PhpParser\Node\Stmt\ClassLike;
-use PhpParser\NodeFinder;
 use PhpParser\NodeTraverser;
 use PhpParser\ParserFactory;
-use PHPUnit\Framework\TestCase;
+use Rector\HttpKernel\RectorKernel;
 use Rector\NodeTypeResolver\NodeVisitor\ParentAndNextNodeVisitor;
 use Rector\PhpParser\Node\BetterNodeFinder;
+use Symplify\PackageBuilder\Tests\AbstractKernelTestCase;
 
-final class BetterNodeFinderTest extends TestCase
+final class BetterNodeFinderTest extends AbstractKernelTestCase
 {
     /**
      * @var Node[]
@@ -28,7 +28,9 @@ final class BetterNodeFinderTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->betterNodeFinder = new BetterNodeFinder(new NodeFinder());
+        $this->bootKernel(RectorKernel::class);
+
+        $this->betterNodeFinder = self::$container->get(BetterNodeFinder::class);
         $this->nodes = $this->createNodesFromFile(__DIR__ . '/Source/SomeFile.php.inc');
     }