[CodeQuality] Add SimplifyForeachToCoalescingRector

packages/CodeQuality/src/Rector/Foreach_/SimplifyForeachToCoalescingRector.php

@@ -0,0 +1,190 @@
+<?php declare(strict_types=1);
+
+namespace Rector\CodeQuality\Rector\Foreach_;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\ArrayDimFetch;
+use PhpParser\Node\Expr\Assign;
+use PhpParser\Node\Expr\BinaryOp\Coalesce;
+use PhpParser\Node\Expr\BinaryOp\Identical;
+use PhpParser\Node\Stmt\Expression;
+use PhpParser\Node\Stmt\Foreach_;
+use PhpParser\Node\Stmt\If_;
+use PhpParser\Node\Stmt\Return_;
+use Rector\NodeTypeResolver\Node\Attribute;
+use Rector\Rector\AbstractRector;
+use Rector\RectorDefinition\CodeSample;
+use Rector\RectorDefinition\RectorDefinition;
+
+final class SimplifyForeachToCoalescingRector extends AbstractRector
+{
+    /**
+     * @var Return_|null
+     */
+    private $returnToBeRemoved;
+
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Changes foreach that returns set value to ??', [
+            new CodeSample(
+                <<<'CODE_SAMPLE'
+foreach ($this->oldToNewFunctions as $oldFunction => $newFunction) {
+    if ($currentFunction === $oldFunction) {
+        return $newFunction;
+    }
+}
+
+return null;
+CODE_SAMPLE
+                ,
+                <<<'CODE_SAMPLE'
+return $this->oldToNewFunctions[$currentFunction] ?? null;
+CODE_SAMPLE
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [Foreach_::class, Return_::class];
+    }
+
+    /**
+     * @param Foreach_|Return_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        if ($node instanceof Return_) {
+            if ($node === $this->returnToBeRemoved) {
+                $this->returnToBeRemoved = null;
+                $this->removeNode = true;
+            }
+
+            return null;
+        }
+
+        if ($this->shouldSkip($node)) {
+            return null;
+        }
+
+        return $this->processForeachNode($node);
+    }
+
+    private function shouldSkip(Foreach_ $foreachNode): bool
+    {
+        if (! $foreachNode->keyVar) {
+            return true;
+        }
+
+        if (count($foreachNode->stmts) !== 1) {
+            return true;
+        }
+
+        $insideForeachStmt = $foreachNode->stmts[0];
+        if (! $insideForeachStmt instanceof If_) {
+            return true;
+        }
+
+        if (! $insideForeachStmt->cond instanceof Identical) {
+            return true;
+        }
+
+        if (count($insideForeachStmt->stmts) !== 1) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private function processForeachNode(Foreach_ $node): ?Node
+    {
+        /** @var If_ $insideForeachStmt */
+        $insideForeachStmt = $node->stmts[0];
+
+        $returnOrAssignNode = $insideForeachStmt->stmts[0];
+
+        /** @var Return_|Assign|null $insideReturnOrAssignNode */
+        $insideReturnOrAssignNode = $returnOrAssignNode instanceof Expression ? $returnOrAssignNode->expr : $returnOrAssignNode;
+        if ($insideReturnOrAssignNode === null) {
+            return null;
+        }
+
+        // return $newValue;
+        // we don't return the node value
+        if (! $this->areNodesEqual($node->valueVar, $insideReturnOrAssignNode->expr)) {
+            return null;
+        }
+
+        if ($insideReturnOrAssignNode instanceof Return_) {
+            return $this->processForeachNodeWithReturnInside($node, $insideReturnOrAssignNode);
+        }
+
+        if ($insideReturnOrAssignNode instanceof Assign) {
+            return $this->processForeachNodeWithAssignInside($node, $insideReturnOrAssignNode);
+        }
+    }
+
+    private function processForeachNodeWithReturnInside(Foreach_ $foreachNode, Return_ $returnNode): ?Node
+    {
+        if (! $this->areNodesEqual($foreachNode->valueVar, $returnNode->expr)) {
+            return null;
+        }
+
+        /** @var If_ $ifNode */
+        $ifNode = $foreachNode->stmts[0];
+
+        /** @var Identical $identicalNode */
+        $identicalNode = $ifNode->cond;
+
+        if ($this->areNodesEqual($identicalNode->left, $foreachNode->keyVar)) {
+            $checkedNode = $identicalNode->right;
+        } elseif ($this->areNodesEqual($identicalNode->right, $foreachNode->keyVar)) {
+            $checkedNode = $identicalNode->left;
+        } else {
+            return null;
+        }
+
+        // is next node Return?
+        if ($foreachNode->getAttribute(Attribute::NEXT_NODE) instanceof Return_) {
+            $this->returnToBeRemoved = $foreachNode->getAttribute(Attribute::NEXT_NODE);
+        }
+
+        $coalesceNode = new Coalesce(new ArrayDimFetch(
+            $foreachNode->expr,
+            $checkedNode
+        ), $this->returnToBeRemoved ? $this->returnToBeRemoved->expr : $checkedNode);
+
+        if ($this->returnToBeRemoved) {
+            return new Return_($coalesceNode);
+        }
+
+        return null;
+    }
+
+    private function processForeachNodeWithAssignInside(Foreach_ $foreachNode, Assign $assignNode): ?Node
+    {
+        /** @var If_ $ifNode */
+        $ifNode = $foreachNode->stmts[0];
+
+        /** @var Identical $identicalNode */
+        $identicalNode = $ifNode->cond;
+
+        if ($this->areNodesEqual($identicalNode->left, $foreachNode->keyVar)) {
+            $checkedNode = $assignNode->var;
+        } elseif ($this->areNodesEqual($identicalNode->right, $foreachNode->keyVar)) {
+            $checkedNode = $assignNode->var;
+        } else {
+            return null;
+        }
+
+        $assignNode = new Assign($checkedNode, new Coalesce(new ArrayDimFetch(
+            $foreachNode->expr,
+            $foreachNode->valueVar
+        ), $checkedNode));
+
+        return new Expression($assignNode);
+    }
+}

packages/CodeQuality/tests/Rector/Foreach_/SimplifyForeachToCoalescingRector/Correct/correct.php.inc

@@ -0,0 +1,9 @@
+<?php
+
+return $this->oldToNewFunctions[$currentFunction] ?? 45;
+foreach ($this->oldToNewFunctions as $oldFunction => $newFunction) {
+    if ($currentFunction === $oldFunction) {
+        return 15;
+    }
+}
+return 0;

packages/CodeQuality/tests/Rector/Foreach_/SimplifyForeachToCoalescingRector/Correct/correct2.php.inc

@@ -0,0 +1,3 @@
+<?php
+
+return $this->oldToNewFunctions[$currentFunction] ?? 45;

packages/CodeQuality/tests/Rector/Foreach_/SimplifyForeachToCoalescingRector/Correct/correct3.php.inc

@@ -0,0 +1,6 @@
+<?php
+
+$newValue = null;
+$values = [];
+
+$newValue = $values[$value] ?? $newValue;

packages/CodeQuality/tests/Rector/Foreach_/SimplifyForeachToCoalescingRector/SimplifyForeachToCoalescingRectorTest.php

@@ -0,0 +1,32 @@
+<?php declare(strict_types=1);
+
+namespace Rector\CodeQuality\Tests\Rector\Foreach_\SimplifyForeachToCoalescingRector;
+
+use Iterator;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+/**
+ * @covers \Rector\CodeQuality\Rector\Foreach_\SimplifyForeachToCoalescingRector
+ */
+final class SimplifyForeachToCoalescingRectorTest extends AbstractRectorTestCase
+{
+    /**
+     * @dataProvider provideWrongToFixedFiles()
+     */
+    public function test(string $wrong, string $fixed): void
+    {
+        $this->doTestFileMatchesExpectedContent($wrong, $fixed);
+    }
+
+    public function provideWrongToFixedFiles(): Iterator
+    {
+        yield [__DIR__ . '/Wrong/wrong.php.inc', __DIR__ . '/Correct/correct.php.inc'];
+        yield [__DIR__ . '/Wrong/wrong2.php.inc', __DIR__ . '/Correct/correct2.php.inc'];
+        yield [__DIR__ . '/Wrong/wrong3.php.inc', __DIR__ . '/Correct/correct3.php.inc'];
+    }
+
+    protected function provideConfig(): string
+    {
+        return __DIR__ . '/config.yml';
+    }
+}

packages/CodeQuality/tests/Rector/Foreach_/SimplifyForeachToCoalescingRector/Wrong/wrong.php.inc

@@ -0,0 +1,16 @@
+<?php
+
+foreach ($this->oldToNewFunctions as $oldFunction => $newFunction) {
+    if ($currentFunction === $oldFunction) {
+        return $newFunction;
+    }
+}
+
+return 45;
+
+foreach ($this->oldToNewFunctions as $oldFunction => $newFunction) {
+    if ($currentFunction === $oldFunction) {
+        return 15;
+    }
+}
+return 0;

packages/CodeQuality/tests/Rector/Foreach_/SimplifyForeachToCoalescingRector/Wrong/wrong2.php.inc

@@ -0,0 +1,9 @@
+<?php
+
+foreach ($this->oldToNewFunctions as $oldFunction => $newFunction) {
+    if ($oldFunction === $currentFunction) {
+        return $newFunction;
+    }
+}
+
+return 45;

packages/CodeQuality/tests/Rector/Foreach_/SimplifyForeachToCoalescingRector/Wrong/wrong3.php.inc

@@ -0,0 +1,10 @@
+<?php
+
+$newValue = null;
+$values = [];
+
+foreach ($values as $key => $value) {
+    if ($key === $input) {
+        $newValue = $value;
+    }
+}

packages/CodeQuality/tests/Rector/Foreach_/SimplifyForeachToCoalescingRector/config.yml

@@ -0,0 +1,2 @@
+services:
+    Rector\CodeQuality\Rector\Foreach_\SimplifyForeachToCoalescingRector: ~