From 22eb1dd9a335a3b64ce7a7c1472f80ed35e1b199 Mon Sep 17 00:00:00 2001
From: Tomas Votruba <tomas.vot@gmail.com>
Date: Fri, 4 Sep 2026 18:29:11 +0200
Subject: [PATCH] [Php80] Skip empty string needle in StrContainsRector

strpos()/strstr() with empty needle returned false on PHP < 8, while
str_contains() with empty needle returns true, so the conversion changed
behavior. Skip when the needle is an empty string literal.

Claude-Session: https://claude.ai/code/session_01Hczn76uiK4bDwdHM4rTMui
---
 .../Fixture/skip_empty_needle_strpos.php.inc      | 11 +++++++++++
 .../Fixture/skip_empty_needle_strstr.php.inc      | 11 +++++++++++
 .../Rector/NotIdentical/StrContainsRector.php     | 15 +++++++++++++++
 3 files changed, 37 insertions(+)
 create mode 100644 rules-tests/Php80/Rector/NotIdentical/StrContainsRector/Fixture/skip_empty_needle_strpos.php.inc
 create mode 100644 rules-tests/Php80/Rector/NotIdentical/StrContainsRector/Fixture/skip_empty_needle_strstr.php.inc

diff --git a/rules-tests/Php80/Rector/NotIdentical/StrContainsRector/Fixture/skip_empty_needle_strpos.php.inc b/rules-tests/Php80/Rector/NotIdentical/StrContainsRector/Fixture/skip_empty_needle_strpos.php.inc
new file mode 100644
index 00000000000..479799cdccd
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/StrContainsRector/Fixture/skip_empty_needle_strpos.php.inc
@@ -0,0 +1,11 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\StrContainsRector\Fixture;
+
+class SkipEmptyNeedleStrpos
+{
+    public function run()
+    {
+        return strpos('abc', '') !== false;
+    }
+}
diff --git a/rules-tests/Php80/Rector/NotIdentical/StrContainsRector/Fixture/skip_empty_needle_strstr.php.inc b/rules-tests/Php80/Rector/NotIdentical/StrContainsRector/Fixture/skip_empty_needle_strstr.php.inc
new file mode 100644
index 00000000000..1ff0abf9c7c
--- /dev/null
+++ b/rules-tests/Php80/Rector/NotIdentical/StrContainsRector/Fixture/skip_empty_needle_strstr.php.inc
@@ -0,0 +1,11 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\NotIdentical\StrContainsRector\Fixture;
+
+class SkipEmptyNeedleStrstr
+{
+    public function run()
+    {
+        return strstr('abc', '') !== false;
+    }
+}
diff --git a/rules/Php80/Rector/NotIdentical/StrContainsRector.php b/rules/Php80/Rector/NotIdentical/StrContainsRector.php
index 11d2bb7b708..8eea1be2831 100644
--- a/rules/Php80/Rector/NotIdentical/StrContainsRector.php
+++ b/rules/Php80/Rector/NotIdentical/StrContainsRector.php
@@ -15,6 +15,7 @@
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Name;
 use PhpParser\Node\Scalar\Int_;
+use PhpParser\Node\Scalar\String_;
 use Rector\Php80\NodeResolver\StrFalseComparisonResolver;
 use Rector\Rector\AbstractRector;
 use Rector\ValueObject\PhpVersionFeature;
@@ -97,6 +98,11 @@ public function refactor(Node $node): ?Node
             return null;
         }
 
+        $args = $funcCall->getArgs();
+        if (isset($args[1]) && $this->isEmptyStringNeedle($args[1]->value)) {
+            return null;
+        }
+
         if (isset($funcCall->getArgs()[2])) {
             $secondArg = $funcCall->getArgs()[2];
 
@@ -132,4 +138,13 @@ private function isIntegerZero(Expr $expr): bool
 
         return $expr->value === 0;
     }
+
+    private function isEmptyStringNeedle(Expr $expr): bool
+    {
+        if (! $expr instanceof String_) {
+            return false;
+        }
+
+        return $expr->value === '';
+    }
 }