[CodeQuality] Handle possibly has '0' value on string on ExplicitBool…

…CompareRector (#709)

* [CodeQuality] Skip explode() on ExplicitBoolCompareRector

* Fixed 🎉

* clean up

* update failing fixture

* Fixed 🎉

* better check

* [ci-review] Rector Rectify

* fix

* naming

* cs fix

* clean up

Co-authored-by: GitHub Action <action@github.com>

rules-tests/CodeQuality/Rector/If_/ExplicitBoolCompareRector/Fixture/explode.php.inc

@@ -0,0 +1,37 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\If_\ExplicitBoolCompareRector\Fixture;
+
+class SomeExplode
+{
+    public function run()
+    {
+        $values = explode('_', 'a_0_b');
+        foreach ($values as $value) {
+            if ($value) {
+                echo $value . PHP_EOL;
+            }
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\If_\ExplicitBoolCompareRector\Fixture;
+
+class SomeExplode
+{
+    public function run()
+    {
+        $values = explode('_', 'a_0_b');
+        foreach ($values as $value) {
+            if ($value !== '' && $value !== '0') {
+                echo $value . PHP_EOL;
+            }
+        }
+    }
+}
+
+?>

rules-tests/CodeQuality/Rector/If_/ExplicitBoolCompareRector/Fixture/string.php.inc

@@ -26,11 +26,11 @@ final class ExplicitString
 {
     public function run(string $item)
     {
-        if ($item === '') {
+        if ($item === '' || $item === '0') {
             return 'empty';
         }
 
-        if ($item !== '') {
+        if ($item !== '' && $item !== '0') {
             return 'not empty';
         }
     }

rules-tests/CodeQuality/Rector/If_/ExplicitBoolCompareRector/Fixture/string_known_value.php.inc

@@ -0,0 +1,53 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\If_\ExplicitBoolCompareRector\Fixture;
+
+final class StringKnownvalue
+{
+    public function run()
+    {
+        $item = 'a value';
+
+        if (!$item) {
+            return 'empty';
+        }
+    }
+
+    public function run2()
+    {
+        $item = 'a value';
+
+        if ($item) {
+            return 'not empty';
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\If_\ExplicitBoolCompareRector\Fixture;
+
+final class StringKnownvalue
+{
+    public function run()
+    {
+        $item = 'a value';
+
+        if ($item === '') {
+            return 'empty';
+        }
+    }
+
+    public function run2()
+    {
+        $item = 'a value';
+
+        if ($item !== '') {
+            return 'not empty';
+        }
+    }
+}
+
+?>

rules-tests/CodeQuality/Rector/If_/ExplicitBoolCompareRector/Fixture/string_known_value2.php.inc

@@ -0,0 +1,53 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\If_\ExplicitBoolCompareRector\Fixture;
+
+final class StringKnownvalue2
+{
+    public function run()
+    {
+        $item = '';
+
+        if (!$item) {
+            return 'empty';
+        }
+    }
+
+    public function run2()
+    {
+        $item = '';
+
+        if ($item) {
+            return 'not empty';
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\If_\ExplicitBoolCompareRector\Fixture;
+
+final class StringKnownvalue2
+{
+    public function run()
+    {
+        $item = '';
+
+        if ($item === '') {
+            return 'empty';
+        }
+    }
+
+    public function run2()
+    {
+        $item = '';
+
+        if ($item !== '') {
+            return 'not empty';
+        }
+    }
+}
+
+?>

rules-tests/CodeQuality/Rector/If_/ExplicitBoolCompareRector/Fixture/string_known_value3.php.inc

@@ -0,0 +1,53 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\If_\ExplicitBoolCompareRector\Fixture;
+
+final class StringSingleChar
+{
+    public function run()
+    {
+        $item = 'a';
+
+        if (!$item) {
+            return 'empty';
+        }
+    }
+
+    public function run2()
+    {
+        $item = 'a';
+
+        if ($item) {
+            return 'not empty';
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\If_\ExplicitBoolCompareRector\Fixture;
+
+final class StringSingleChar
+{
+    public function run()
+    {
+        $item = 'a';
+
+        if ($item === '0') {
+            return 'empty';
+        }
+    }
+
+    public function run2()
+    {
+        $item = 'a';
+
+        if ($item !== '0') {
+            return 'not empty';
+        }
+    }
+}
+
+?>

rules/CodeQuality/Rector/If_/ExplicitBoolCompareRector.php

@@ -8,6 +8,8 @@
 use PhpParser\Node\Expr;
 use PhpParser\Node\Expr\Array_;
 use PhpParser\Node\Expr\BinaryOp;
+use PhpParser\Node\Expr\BinaryOp\BooleanAnd;
+use PhpParser\Node\Expr\BinaryOp\BooleanOr;
 use PhpParser\Node\Expr\BinaryOp\Greater;
 use PhpParser\Node\Expr\BinaryOp\Identical;
 use PhpParser\Node\Expr\BinaryOp\NotIdentical;
@@ -182,16 +184,61 @@ private function resolveArray(bool $isNegated, Expr $expr): ?BinaryOp
         return new NotIdentical($expr, $array);
     }
 
-    private function resolveString(bool $isNegated, Expr $expr): Identical | NotIdentical
+    private function resolveString(bool $isNegated, Expr $expr): Identical | NotIdentical | BooleanAnd | BooleanOr
     {
         $string = new String_('');
 
-        // compare === ''
-        if ($isNegated) {
-            return new Identical($expr, $string);
+        $identical = $this->resolveIdentical($expr, $isNegated, $string);
+
+        $value = $this->valueResolver->getValue($expr);
+
+        // unknown value. may be from parameter
+        if ($value === null) {
+            return $this->resolveZeroIdenticalstring($identical, $isNegated, $expr);
+        }
+
+        $length = strlen($value);
+
+        if ($length === 1) {
+            $string = new String_('0');
+            return $this->resolveIdentical($expr, $isNegated, $string);
         }
 
-        return new NotIdentical($expr, $string);
+        return $identical;
+    }
+
+    private function resolveIdentical(Expr $expr, bool $isNegated, String_ $string): Identical | NotIdentical
+    {
+        /**
+         * // compare === ''
+         *
+         * @var Identical|NotIdentical $identical
+         */
+        $identical = $isNegated
+            ? new Identical($expr, $string)
+            : new NotIdentical($expr, $string);
+
+        return $identical;
+    }
+
+    private function resolveZeroIdenticalstring(
+        Identical | NotIdentical $identical,
+        bool $isNegated,
+        Expr $expr
+    ): BooleanAnd | BooleanOr {
+        $string = new String_('0');
+        $zeroIdentical = $isNegated
+            ? new Identical($expr, $string)
+            : new NotIdentical($expr, $string);
+
+        /**
+         * @var BooleanAnd|BooleanOr $result
+         */
+        $result = $isNegated
+            ? new BooleanOr($identical, $zeroIdentical)
+            : new BooleanAnd($identical, $zeroIdentical);
+
+        return $result;
     }
 
     private function resolveInteger(bool $isNegated, Expr $expr): Identical | NotIdentical