From 393a98bab1f0277fc266940fd3614f0f46f6e14b Mon Sep 17 00:00:00 2001
From: "agent:orchestrator" <mechgw@gmail.com>
Date: Wed, 14 Oct 2026 20:14:23 +0200
Subject: [PATCH] fix: generate mutations of mutators requested outside the
 default sets

The mutators applicable to a file were looked up in a map built from the
default sets, so a mutator disabled in its set (NotEmptyStringToEmpty) never
mutated anything, even when requested with --mutator.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 src/Support/MutationGenerator.php    | 10 ++--------
 tests/Unit/MutationGeneratorTest.php | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/Support/MutationGenerator.php b/src/Support/MutationGenerator.php
index cebc859..b80a451 100644
--- a/src/Support/MutationGenerator.php
+++ b/src/Support/MutationGenerator.php
@@ -200,13 +200,7 @@ public function enterNode(Node $node): ?Node
 
         $nodeTypes = array_unique($nodeTypes);
 
-        $mutatorsToUse = [];
-        foreach ($nodeTypes as $nodeType) {
-            foreach (MutatorMap::get()[$nodeType] ?? [] as $mutator) {
-                $mutatorsToUse[] = $mutator;
-            }
-        }
-
-        return array_intersect($mutators, $mutatorsToUse);
+        // a mutator may be requested explicitly although it is not part of any default set
+        return array_filter($mutators, fn (string $mutator): bool => array_intersect($mutator::nodesToHandle(), $nodeTypes) !== []);
     }
 }
diff --git a/tests/Unit/MutationGeneratorTest.php b/tests/Unit/MutationGeneratorTest.php
index 79c67ed..87ed9fc 100644
--- a/tests/Unit/MutationGeneratorTest.php
+++ b/tests/Unit/MutationGeneratorTest.php
@@ -5,6 +5,7 @@
 use Pest\Mutate\Mutators\ControlStructures\IfNegated;
 use Pest\Mutate\Mutators\Equality\GreaterOrEqualToGreater;
 use Pest\Mutate\Mutators\Equality\SmallerToSmallerOrEqual;
+use Pest\Mutate\Mutators\String\NotEmptyStringToEmpty;
 use Pest\Mutate\Support\MutationGenerator;
 use Pest\Mutate\Support\PhpParserFactory;
 use Symfony\Component\Finder\SplFileInfo;
@@ -286,3 +287,19 @@ function test() {
     expect($mutations)
         ->toBeEmpty();
 });
+
+it('generates mutations of a mutator requested outside the default sets', function (): void {
+    $mutations = ($this->generate)(<<<'PHP'
+            <?php
+
+            function greet(): string {
+                return 'Hello';
+            }
+            PHP,
+        [NotEmptyStringToEmpty::class],
+    );
+
+    expect($mutations)
+        ->toHaveCount(1)
+        ->and($mutations[0]->mutator)->toBe(NotEmptyStringToEmpty::class);
+});