[DeadCode] RemoveUnusedElseForReturnedValueRector

abz/UnderElse.php

@@ -0,0 +1,14 @@
+<?php declare(strict_types=1);
+
+
+final class UnderElse
+{
+    public function run($value)
+    {
+        if ($value) {
+            return 5;
+        } else {
+            return 10;
+        }
+    }
+}

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

@@ -30,3 +30,4 @@ services:
     Rector\DeadCode\Rector\Stmt\RemoveUnreachableStatementRector: ~
     Rector\DeadCode\Rector\If_\SimplifyIfElseWithSameContentRector: ~
     Rector\DeadCode\Rector\Ternary\TernaryToBooleanOrFalseToBooleanAndRector: ~
+    Rector\DeadCode\Rector\FunctionLike\RemoveUnusedElseForReturnedValueRector: ~

packages/DeadCode/src/Rector/FunctionLike/RemoveUnusedElseForReturnedValueRector.php

@@ -0,0 +1,97 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\DeadCode\Rector\FunctionLike;
+
+use PhpParser\Node;
+use PhpParser\Node\FunctionLike;
+use PhpParser\Node\Stmt\If_;
+use Rector\PhpParser\Node\Manipulator\IfManipulator;
+use Rector\Rector\AbstractRector;
+use Rector\RectorDefinition\CodeSample;
+use Rector\RectorDefinition\RectorDefinition;
+
+/**
+ * @see \Rector\DeadCode\Tests\Rector\FunctionLike\RemoveUnusedElseForReturnedValueRector\RemoveUnusedElseForReturnedValueRectorTest
+ */
+final class RemoveUnusedElseForReturnedValueRector extends AbstractRector
+{
+    /**
+     * @var IfManipulator
+     */
+    private $ifManipulator;
+
+    public function __construct(IfManipulator $ifManipulator)
+    {
+        $this->ifManipulator = $ifManipulator;
+    }
+
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Remove if for last else, if previous values were awlways returned', [
+            new CodeSample(
+                <<<'PHP'
+class SomeClass
+{
+    public function run($value)
+    {
+        if ($value) {
+            return 5;
+        } else {
+            return 10;
+        }
+    }
+}
+PHP
+,
+                <<<'PHP'
+class SomeClass
+{
+    public function run($value)
+    {
+        if ($value) {
+            return 5;
+        }
+
+        return 10;
+    }
+}
+PHP
+
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [FunctionLike::class];
+    }
+
+    /**
+     * @param FunctionLike $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        $this->traverseNodesWithCallable((array) $node->getStmts(), function (Node $node) {
+            if (! $node instanceof If_) {
+                return null;
+            }
+
+            if (! $this->ifManipulator->isWithElseAlwaysReturnValue($node)) {
+                return null;
+            }
+
+            foreach ($node->else->stmts as $elseStmt) {
+                $this->addNodeAfterNode($elseStmt, $node);
+            }
+
+            $node->else = null;
+        });
+
+        return $node;
+    }
+}

packages/DeadCode/tests/Rector/FunctionLike/RemoveUnusedElseForReturnedValueRector/Fixture/fixture.php.inc

@@ -0,0 +1,34 @@
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\FunctionLike\RemoveUnusedElseForReturnedValueRector\Fixture;
+
+class SomeClass
+{
+    public function run($value)
+    {
+        if ($value) {
+            return 5;
+        } else {
+            return 10;
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\FunctionLike\RemoveUnusedElseForReturnedValueRector\Fixture;
+
+class SomeClass
+{
+    public function run($value)
+    {
+        if ($value) {
+            return 5;
+        }
+        return 10;
+    }
+}
+
+?>

packages/DeadCode/tests/Rector/FunctionLike/RemoveUnusedElseForReturnedValueRector/Fixture/skip_non_first_level.php.inc

@@ -0,0 +1,19 @@
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\FunctionLike\RemoveUnusedElseForReturnedValueRector\Fixture;
+
+use PhpParser\Node\Expr\BinaryOp\Equal;
+
+class SkipNonFirstLevel
+{
+    public function test($node)
+    {
+        if ($node->cond instanceof Equal) {
+            if ($node->stmts[0]->expr === null) {
+                return null;
+            }
+        } else {
+            return null;
+        }
+    }
+}

packages/DeadCode/tests/Rector/FunctionLike/RemoveUnusedElseForReturnedValueRector/Fixture/skip_not_only_else.php.inc

@@ -0,0 +1,39 @@
+<?php
+
+namespace Rector\DeadCode\Tests\Rector\FunctionLike\RemoveUnusedElseForReturnedValueRector\Fixture;
+
+class SkipNotOnlyElse
+{
+    public function run($value)
+    {
+        if ($value) {
+            return 5;
+        } elseif ($value- 1) {
+            $value = 55;
+            return;
+        } else {
+            return 10;
+        }
+    }
+
+    public function runAgain($value)
+    {
+        if ($value) {
+            return 5;
+        } elseif ($value- 1) {
+            $value = 55;
+            return 10;
+        } else {
+            return;
+        }
+    }
+
+    public function runAgainAndAgain($value)
+    {
+        if ($value) {
+            5 + 10;
+        } else {
+            return $value;
+        }
+    }
+}

packages/DeadCode/tests/Rector/FunctionLike/RemoveUnusedElseForReturnedValueRector/RemoveUnusedElseForReturnedValueRectorTest.php

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

src/PhpParser/Node/Manipulator/IfManipulator.php

@@ -4,11 +4,17 @@ declare(strict_types=1);
 
 namespace Rector\PhpParser\Node\Manipulator;
 
+use PhpParser\Node;
 use PhpParser\Node\Expr;
 use PhpParser\Node\Expr\BinaryOp\Identical;
 use PhpParser\Node\Expr\BinaryOp\NotIdentical;
+use PhpParser\Node\Stmt\Do_;
+use PhpParser\Node\Stmt\Else_;
 use PhpParser\Node\Stmt\If_;
 use PhpParser\Node\Stmt\Return_;
+use PhpParser\Node\Stmt\While_;
+use PhpParser\NodeTraverser;
+use Rector\PhpParser\NodeTraverser\CallableNodeTraverser;
 use Rector\PhpParser\Printer\BetterStandardPrinter;
 
 final class IfManipulator
@@ -23,12 +29,19 @@ final class IfManipulator
      */
     private $constFetchManipulator;
 
+    /**
+     * @var CallableNodeTraverser
+     */
+    private $callableNodeTraverser;
+
     public function __construct(
         BetterStandardPrinter $betterStandardPrinter,
-        ConstFetchManipulator $constFetchManipulator
+        ConstFetchManipulator $constFetchManipulator,
+        CallableNodeTraverser $callableNodeTraverser
     ) {
         $this->betterStandardPrinter = $betterStandardPrinter;
         $this->constFetchManipulator = $constFetchManipulator;
+        $this->callableNodeTraverser = $callableNodeTraverser;
     }
 
     /**
@@ -98,6 +111,25 @@ final class IfManipulator
         return null;
     }
 
+    public function isWithElseAlwaysReturnValue(If_ $if): bool
+    {
+        if (! $this->isAlwaysReturnValue((array) $if->stmts)) {
+            return false;
+        }
+
+        foreach ($if->elseifs as $elseif) {
+            if (! $this->isAlwaysReturnValue((array) $elseif->stmts)) {
+                return false;
+            }
+        }
+
+        if ($if->else === null) {
+            return false;
+        }
+
+        return $this->isAlwaysReturnValue((array) $if->else->stmts);
+    }
+
     private function matchComparedAndReturnedNode(NotIdentical $notIdentical, Return_ $returnNode): ?Expr
     {
         if ($this->betterStandardPrinter->areNodesEqual($notIdentical->left, $returnNode->expr)) {
@@ -114,4 +146,46 @@ final class IfManipulator
 
         return null;
     }
+
+    private function isAlwaysReturnValue(array $stmts): bool
+    {
+        $isAlwaysReturnValue = false;
+
+        $this->callableNodeTraverser->traverseNodesWithCallable($stmts, function (Node $node) use (
+            &$isAlwaysReturnValue
+        ) {
+            if ($this->isScopeChangingNode($node)) {
+                $isAlwaysReturnValue = false;
+
+                return NodeTraverser::STOP_TRAVERSAL;
+            }
+
+            if ($node instanceof Return_) {
+                if ($node->expr === null) {
+                    $isAlwaysReturnValue = false;
+
+                    return NodeTraverser::STOP_TRAVERSAL;
+                }
+
+                $isAlwaysReturnValue = true;
+            }
+        });
+
+        return $isAlwaysReturnValue;
+    }
+
+    private function isScopeChangingNode(Node $node): bool
+    {
+        $scopeChangingNodes = [Do_::class, While_::class, If_::class, Else_::class];
+
+        foreach ($scopeChangingNodes as $scopeChangingNode) {
+            if (! is_a($node, $scopeChangingNode, true)) {
+                continue;
+            }
+
+            return true;
+        }
+
+        return false;
+    }
 }