handle cases where strlen arg is a Stringable object (#981)

* handle cases where strlen arg is a Stringable object

* handle in processLeftIdentical as well

* fix to use getNativeType

* add test fixtures

* stick on strict comparison by using string cast

* fix return type

* refactor processIdentical

* refactor processEqual

* fix

* separate expr to variable

rules-tests/CodeQuality/Rector/Identical/StrlenZeroToIdenticalEmptyStringRector/Fixture/definitely_string.php.inc

@@ -2,9 +2,9 @@
 
 namespace Rector\Tests\CodeQuality\Rector\Identical\StrlenZeroToIdenticalEmptyStringRector\Fixture;
 
-class Fixture
+class DefinitelyString
 {
-    public function run($value)
+    public function run(string $value)
     {
         $empty = strlen($value) === 0;
 
@@ -18,9 +18,9 @@ class Fixture
 
 namespace Rector\Tests\CodeQuality\Rector\Identical\StrlenZeroToIdenticalEmptyStringRector\Fixture;
 
-class Fixture
+class DefinitelyString
 {
-    public function run($value)
+    public function run(string $value)
     {
         $empty = $value === '';
 

rules-tests/CodeQuality/Rector/Identical/StrlenZeroToIdenticalEmptyStringRector/Fixture/might_not_be_string.php.inc

@@ -0,0 +1,31 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\Identical\StrlenZeroToIdenticalEmptyStringRector\Fixture;
+
+class MightNotBeString
+{
+    public function run($value)
+    {
+        $empty = strlen($value) === 0;
+
+        $empty = 0 === strlen($value);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\Identical\StrlenZeroToIdenticalEmptyStringRector\Fixture;
+
+class MightNotBeString
+{
+    public function run($value)
+    {
+        $empty = (string) $value === '';
+
+        $empty = (string) $value === '';
+    }
+}
+
+?>

rules-tests/CodeQuality/Rector/Identical/StrlenZeroToIdenticalEmptyStringRector/Fixture/non_string_value.php.inc

@@ -0,0 +1,35 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\Identical\StrlenZeroToIdenticalEmptyStringRector\Fixture;
+
+class NonStringValue
+{
+    public function run()
+    {
+        $value = null;
+
+        $empty = strlen($value) === 0;
+
+        $empty = 0 === strlen($value);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\Identical\StrlenZeroToIdenticalEmptyStringRector\Fixture;
+
+class NonStringValue
+{
+    public function run()
+    {
+        $value = null;
+
+        $empty = (string) $value === '';
+
+        $empty = (string) $value === '';
+    }
+}
+
+?>

rules-tests/CodeQuality/Rector/Identical/StrlenZeroToIdenticalEmptyStringRector/Fixture/stringable_object.php.inc

@@ -0,0 +1,51 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\Identical\StrlenZeroToIdenticalEmptyStringRector\Fixture;
+
+class Stringable {
+    private string $string = '';
+
+    public function __toString() : string {
+        return $this->string;
+    }
+}
+
+class StringableObject
+{
+    public function run()
+    {
+        $value = new Stringable();
+
+        $empty = strlen($value) === 0;
+
+        $empty = 0 === strlen($value);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\Identical\StrlenZeroToIdenticalEmptyStringRector\Fixture;
+
+class Stringable {
+    private string $string = '';
+
+    public function __toString() : string {
+        return $this->string;
+    }
+}
+
+class StringableObject
+{
+    public function run()
+    {
+        $value = new Stringable();
+
+        $empty = (string) $value === '';
+
+        $empty = (string) $value === '';
+    }
+}
+
+?>

rules/CodeQuality/Rector/Identical/StrlenZeroToIdenticalEmptyStringRector.php

@@ -11,6 +11,8 @@ use PhpParser\Node\Expr\BinaryOp\Identical;
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Scalar\String_;
 use Rector\Core\NodeAnalyzer\ArgsAnalyzer;
+use PhpParser\Node\Expr\BinaryOp\Equal;
+use PHPStan\Type\StringType;
 use Rector\Core\Rector\AbstractRector;
 use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
 use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
@@ -34,7 +36,7 @@ final class StrlenZeroToIdenticalEmptyStringRector extends AbstractRector
                     <<<'CODE_SAMPLE'
 class SomeClass
 {
-    public function run($value)
+    public function run(string $value)
     {
         $empty = strlen($value) === 0;
     }
@@ -44,7 +46,7 @@ CODE_SAMPLE
                     <<<'CODE_SAMPLE'
 class SomeClass
 {
-    public function run($value)
+    public function run(string $value)
     {
         $empty = $value === '';
     }
@@ -69,23 +71,23 @@ CODE_SAMPLE
     public function refactor(Node $node): ?Node
     {
         if ($node->left instanceof FuncCall) {
-            return $this->processLeftIdentical($node, $node->left);
+            return $this->processIdentical($node->right, $node->left);
         }
 
         if ($node->right instanceof FuncCall) {
-            return $this->processRightIdentical($node, $node->right);
+            return $this->processIdentical($node->left, $node->right);
         }
 
         return null;
     }
 
-    private function processLeftIdentical(Identical $identical, FuncCall $funcCall): ?Identical
+    private function processIdentical(Expr $value, FuncCall $funcCall): ?Identical
     {
         if (! $this->isName($funcCall, 'strlen')) {
             return null;
         }
 
-        if (! $this->valueResolver->isValue($identical->right, 0)) {
+        if (! $this->valueResolver->isValue($value, 0)) {
             return null;
         }
 
@@ -98,28 +100,13 @@ CODE_SAMPLE
         /** @var Expr $variable */
         $variable = $firstArg->value;
 
-        return new Identical($variable, new String_(''));
-    }
-
-    private function processRightIdentical(Identical $identical, FuncCall $funcCall): ?Identical
-    {
-        if (! $this->isName($funcCall, 'strlen')) {
-            return null;
+        // Needs string cast if variable type is not string
+        // see https://github.com/rectorphp/rector/issues/6700
+        $isStringType = $this->nodeTypeResolver->getNativeType($variable) instanceof StringType;
+        if (!$isStringType) {
+            return new Identical(new Expr\Cast\String_($variable), new String_(''));
         }
 
-        if (! $this->valueResolver->isValue($identical->left, 0)) {
-            return null;
-        }
-
-        if (! $this->argsAnalyzer->isArgInstanceInArgsPosition($funcCall->args, 0)) {
-            return null;
-        }
-
-        /** @var Arg $firstArg */
-        $firstArg = $funcCall->args[0];
-        /** @var Expr $variable */
-        $variable = $firstArg->value;
-
         return new Identical($variable, new String_(''));
     }
 }