Fix NullToStrictStringFuncCallArgRector with probabilistic check for plural array passed to function where array allowed

Author: TomasVotruba

rules-tests/Php81/Rector/FuncCall/NullToStrictStringFuncCallArgRector/Fixture/skip_preg_replace.php.inc

@@ -0,0 +1,13 @@
+<?php
+
+namespace Rector\Tests\Php81\Rector\FuncCall\NullToStrictStringFuncCallArgRector\Fixture;
+
+final class SkipPregReplace
+{
+    public static function run(&$items)
+    {
+        $pattern = "/(\d+')/";
+        $replacement = '$1';
+        $items = preg_replace($pattern, $replacement, $items);
+    }
+}

rules/Php81/NodeManipulator/NullToStrictStringIntConverter.php

@@ -11,6 +11,7 @@
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\MethodCall;
 use PhpParser\Node\Expr\Ternary;
+use PhpParser\Node\Expr\Variable;
 use PhpParser\Node\Scalar\Int_;
 use PhpParser\Node\Scalar\InterpolatedString;
 use PhpParser\Node\Scalar\String_;
@@ -62,9 +63,9 @@ public function convertIfNull(
             return null;
         }
 
-        $parameter = $parametersAcceptor->getParameters()[$position] ?? null;
-        if ($parameter instanceof ExtendedNativeParameterReflection && $parameter->getType() instanceof UnionType) {
-            $parameterType = $parameter->getType();
+        $parameterReflection = $parametersAcceptor->getParameters()[$position] ?? null;
+        if ($parameterReflection instanceof ExtendedNativeParameterReflection && $parameterReflection->getType() instanceof UnionType) {
+            $parameterType = $parameterReflection->getType();
             if (! $this->isValidUnionType($parameterType)) {
                 return null;
             }
@@ -109,6 +110,10 @@ private function shouldSkipValue(Expr $expr, Scope $scope, bool $isTrait, string
             return true;
         }
 
+        if ($this->isPossibleArrayVariableName($type, $nativeType, $expr)) {
+            return true;
+        }
+
         if ($this->shouldSkipType($type)) {
             return true;
         }
@@ -193,4 +198,27 @@ private function isAnErrorType(Expr $expr, Type $type, Scope $scope): bool
             && ! $type->isExplicitMixed()
             && $type->getSubtractedType() instanceof NullType;
     }
+
+    /**
+     * @see https://github.com/rectorphp/rector/issues/9447 for context
+     */
+    private function isPossibleArrayVariableName(Type $passedType, Type $reflectionParamType, Expr $expr): bool
+    {
+        // could mixed, resp. array, no need to (string) cast array
+        if (! $passedType instanceof MixedType) {
+            return false;
+        }
+
+        if (! $reflectionParamType->isArray()->maybe()) {
+            return false;
+        }
+
+        if ($expr instanceof Variable && is_string($expr->name)) {
+            $variableName = $expr->name;
+            // most likely plural variable
+            return strlen($variableName) > 3 && str_ends_with($variableName, 's');
+        }
+
+        return false;
+    }
 }

rules/Php81/Rector/FuncCall/NullToStrictStringFuncCallArgRector.php

@@ -87,7 +87,7 @@ public function refactor(Node $node): ?Node
         }
 
         $args = $node->getArgs();
-        $positions = $this->resolvePositions($node, $args, $scope);
+        $positions = $this->resolveStringPositions($node, $args, $scope);
 
         if ($positions === []) {
             return null;
@@ -133,9 +133,9 @@ public function provideMinPhpVersion(): int
 
     /**
      * @param Arg[] $args
-     * @return int[]|string[]
+     * @return int[]
      */
-    private function resolvePositions(FuncCall $funcCall, array $args, Scope $scope): array
+    private function resolveStringPositions(FuncCall $funcCall, array $args, Scope $scope): array
     {
         $positions = [];