[PHP] Add NullCoalesceRector

config/level/php/php70.yml

@@ -1,2 +1,3 @@
 services:
     Rector\Php\Rector\ExceptionHandlerTypehintRector: ~
+    Rector\Php\Rector\TernaryToNullCoalescingRector: ~

packages/Php/src/Rector/ExceptionHandlerTypehintRector.php

@@ -12,7 +12,6 @@ use Rector\RectorDefinition\CodeSample;
 use Rector\RectorDefinition\RectorDefinition;
 
 /**
- * @group php7
  * @source https://wiki.php.net/rfc/typed_properties_v2#proposal
  */
 final class ExceptionHandlerTypehintRector extends AbstractRector

packages/Php/src/Rector/TernaryToNullCoalescingRector.php

@@ -0,0 +1,127 @@
+<?php declare(strict_types=1);
+
+namespace Rector\Php\Rector;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\BinaryOp\Coalesce;
+use PhpParser\Node\Expr\BinaryOp\Identical;
+use PhpParser\Node\Expr\BinaryOp\NotIdentical;
+use PhpParser\Node\Expr\ConstFetch;
+use PhpParser\Node\Expr\Isset_;
+use PhpParser\Node\Expr\Ternary;
+use Rector\Printer\BetterStandardPrinter;
+use Rector\Rector\AbstractRector;
+use Rector\RectorDefinition\CodeSample;
+use Rector\RectorDefinition\RectorDefinition;
+
+final class TernaryToNullCoalescingRector extends AbstractRector
+{
+    /**
+     * @var BetterStandardPrinter
+     */
+    private $betterStandardPrinter;
+
+    public function __construct(BetterStandardPrinter $betterStandardPrinter)
+    {
+        $this->betterStandardPrinter = $betterStandardPrinter;
+    }
+
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition(
+            'Changes unneeded null check to ?? operator',
+            [
+                new CodeSample('$value === null ? 10 : $value;', '$value ?? 10;'),
+                new CodeSample('isset($value) ? $value : 10;', '$value ?? 10;'),
+            ]
+        );
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [Ternary::class];
+    }
+
+    /**
+     * @param Ternary $ternaryNode
+     */
+    public function refactor(Node $ternaryNode): ?Node
+    {
+        if ($ternaryNode->cond instanceof Isset_) {
+            $coalesceNode = $this->processTernaryWithIsset($ternaryNode);
+            if ($coalesceNode) {
+                return $coalesceNode;
+            }
+        }
+
+        if ($ternaryNode->cond instanceof Identical) {
+            [$checkedNode, $fallbackNode] = [$ternaryNode->else, $ternaryNode->if];
+        } elseif ($ternaryNode->cond instanceof NotIdentical) {
+            [$checkedNode, $fallbackNode] = [$ternaryNode->if, $ternaryNode->else];
+        } else {
+            // not a match
+            return $ternaryNode;
+        }
+
+        /** @var Identical|NotIdentical $ternaryCompareNode */
+        $ternaryCompareNode = $ternaryNode->cond;
+
+        if ($this->isNullMatch($ternaryCompareNode->left, $ternaryCompareNode->right, $checkedNode)) {
+            return new Coalesce($checkedNode, $fallbackNode);
+        }
+
+        if ($this->isNullMatch($ternaryCompareNode->right, $ternaryCompareNode->left, $checkedNode)) {
+            return new Coalesce($checkedNode, $fallbackNode);
+        }
+
+        return $ternaryNode;
+    }
+
+    private function processTernaryWithIsset(Ternary $ternaryNode): ?Coalesce
+    {
+        /** @var Isset_ $issetNode */
+        $issetNode = $ternaryNode->cond;
+
+        // none or multiple isset values cannot be handled here
+        if (! isset($issetNode->vars[0]) || count($issetNode->vars) > 1) {
+            return null;
+        }
+
+        if ($ternaryNode->if === null) {
+            return null;
+        }
+
+        $ifContent = $this->betterStandardPrinter->prettyPrint([$ternaryNode->if]);
+        $varNodeContent = $this->betterStandardPrinter->prettyPrint([$issetNode->vars[0]]);
+
+        if ($ifContent === $varNodeContent) {
+            return new Coalesce($ternaryNode->if, $ternaryNode->else);
+        }
+
+        return null;
+    }
+
+    private function isNullMatch(Node $possibleNullNode, Node $firstNode, Node $secondNode): bool
+    {
+        if (! $this->isNullConstant($possibleNullNode)) {
+            return false;
+        }
+
+        $firstNodeContent = $this->betterStandardPrinter->prettyPrint([$firstNode]);
+        $secondNodeContent = $this->betterStandardPrinter->prettyPrint([$secondNode]);
+
+        return $firstNodeContent === $secondNodeContent;
+    }
+
+    private function isNullConstant(Node $node): bool
+    {
+        if (! $node instanceof ConstFetch) {
+            return false;
+        }
+
+        return $node->name->toLowerString() === 'null';
+    }
+}

packages/Php/tests/Rector/TernaryToNullCoalescingRector/Correct/correct.php.inc

@@ -0,0 +1,15 @@
+<?php declare(strict_types=1);
+
+$x = $a ?? null;
+
+$x = $a[0] ?? 1;
+
+$x=$a ?? null;
+
+$x = $a[ $b[ "c"  ]] ?? null;
+
+$x = $a ?? $b[func(1, true)];
+
+$x = ($a ?? isset($b)) ? $b : "";
+
+$x = $a ?? isset($b) ? $b : isset($c) ? $c : "";

packages/Php/tests/Rector/TernaryToNullCoalescingRector/Correct/correct2.php.inc

@@ -0,0 +1,7 @@
+<?php declare(strict_types=1);
+
+$x = $a ?? 1;
+$y = isset($b) ? "b" : 2;
+$x = $c ?? 3;
+
+$x = $a ?? $b ?? "";

packages/Php/tests/Rector/TernaryToNullCoalescingRector/Correct/correct3.php.inc

@@ -0,0 +1,5 @@
+<?php declare(strict_types=1);
+
+$f = $g ?? 'g';
+
+$ff = $gg ?? 'gg';

packages/Php/tests/Rector/TernaryToNullCoalescingRector/Correct/correct4.php.inc

@@ -0,0 +1,25 @@
+<?php declare(strict_types=1);
+
+$d = $e ?? 'e';
+
+$dd = $ee ?? 'ee';
+
+$i = $this->${'a'}[0]->$$b[1][2]::$c[3][4][5]->xxx->{" $d"} ?? 0;
+
+$j = $this->${'a'}[0]->$$b[1][2]::$c[3][4][5]->xxx->{" $d"} ?? false;
+
+$k = $this
+    ->${'a'}[0]
+    ->$$b[1][2]
+    ::$c[3][4][5]
+    ->{" $d"} ?? true;
+
+$l = \Whatever\Something::$anything ?? 1;
+
+$m = $object->anything ?? 0;
+
+$n = ($something ?? false);
+
+$o[$something ?? true] = true;
+
+$p = doSomething()() ?? false;

packages/Php/tests/Rector/TernaryToNullCoalescingRector/TernaryToNullCoalescingRectorTest.php

@@ -0,0 +1,37 @@
+<?php declare(strict_types=1);
+
+namespace Rector\Php\Tests\Rector\TernaryToNullCoalescingRector;
+
+use Iterator;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+/**
+ * @covers \Rector\Php\Rector\TernaryToNullCoalescingRector
+ *
+ * Some tests copied from:
+ * https://github.com/FriendsOfPHP/PHP-CS-Fixer/commit/0db4f91088a3888a7c8b26e5a36fba53c0d9507c#diff-02f477b178d0dc5b25ac05ab3b59e7c7
+ * https://github.com/slevomat/coding-standard/blob/master/tests/Sniffs/ControlStructures/data/requireNullCoalesceOperatorErrors.fixed.php
+ */
+final class TernaryToNullCoalescingRectorTest 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'];
+        yield [__DIR__ . '/Wrong/wrong4.php.inc', __DIR__ . '/Correct/correct4.php.inc'];
+    }
+
+    protected function provideConfig(): string
+    {
+        return __DIR__ . '/config.yml';
+    }
+}

packages/Php/tests/Rector/TernaryToNullCoalescingRector/Wrong/wrong.php.inc

@@ -0,0 +1,15 @@
+<?php declare(strict_types=1);
+
+$x = isset($a) ? $a : null;
+
+$x = isset($a[0]) ? $a[0] : 1;
+
+$x=isset($a)?$a:null;
+
+$x = isset   (  $a[$b["c"]]) ?$a[ $b[ "c"  ]]   : null;
+
+$x = isset($a) ? $a : $b[func(1, true)];
+
+$x = (isset($a) ? $a : isset($b)) ? $b : "";
+
+$x = isset($a) ? $a : isset($b) ? $b : isset($c) ? $c : "";

packages/Php/tests/Rector/TernaryToNullCoalescingRector/Wrong/wrong2.php.inc

@@ -0,0 +1,7 @@
+<?php declare(strict_types=1);
+
+$x = isset($a) ? $a : 1;
+$y = isset($b) ? "b" : 2;
+$x = isset($c) ? $c : 3;
+
+$x = isset($a) ? $a : (isset($b) ? $b : "");

packages/Php/tests/Rector/TernaryToNullCoalescingRector/Wrong/wrong3.php.inc

@@ -0,0 +1,5 @@
+<?php declare(strict_types=1);
+
+$f = $g === null ? 'g' : $g;
+
+$ff = null === $gg ? 'gg' : $gg;

packages/Php/tests/Rector/TernaryToNullCoalescingRector/Wrong/wrong4.php.inc

@@ -0,0 +1,29 @@
+<?php declare(strict_types=1);
+
+$d = $e !== null ? $e : 'e';
+
+$dd = null !== $ee ? $ee : 'ee';
+
+$i = $this->${'a'}[0]->$$b[1][2]::$c[3][4][5]->xxx->{" $d"} !== null ? $this->${'a'}[0]->$$b[1][2]::$c[3][4][5]->xxx->{" $d"} : 0;
+
+$j = $this->${'a'}[0]->$$b[1][2]::$c[3][4][5]->xxx->{" $d"} === null ? false : $this->${'a'}[0]->$$b[1][2]::$c[3][4][5]->xxx->{" $d"};
+
+$k = $this
+    ->${'a'}[0]->$$b[1][2]
+    ::$c[3][4][5]->{" $d"} !== null
+    ? $this
+        ->${'a'}[0]
+        ->$$b[1][2]
+        ::$c[3][4][5]
+        ->{" $d"}
+    : true;
+
+$l = \Whatever\Something::$anything !== null ? \Whatever\Something::$anything : 1;
+
+$m = $object->anything === null ? 0 : $object->anything;
+
+$n = ($something === null ? false : $something);
+
+$o[$something === null ? true : $something] = true;
+
+$p = doSomething()() === null ? false : doSomething()();

packages/Php/tests/Rector/TernaryToNullCoalescingRector/config.yml

@@ -0,0 +1,2 @@
+services:
+    Rector\Php\Rector\TernaryToNullCoalescingRector: ~