[TASK] Attribute CodeFormatRule to YAML files a rule rewrites

- On a file a rule changes, use the re-dumped original as the diff baseline so
  the reported diff shows only the rule's change, and attribute the extra
  reformatting (indentation, comments the YAML dumper cannot keep) to the
  virtual CodeFormatRule
- Leave files no rule touches byte-exact: never re-dump for formatting alone, so
  comment-only files are not rewritten project-wide
- Cover the behaviour with a YamlProcessResult test (rule only, rule plus
  reformat, and a commented file left untouched)

Author: chrissonntag

packages/fractor-yaml/src/YamlFileProcessor.php

@@ -52,13 +52,17 @@ public function handle(File $file, iterable $appliedRules): void
             }
         }
 
-        // Nothing has changed.
+        // Never re-dump for formatting alone: the dumper drops comments, so
+        // untouched files stay byte-exact.
         if ($newYaml === $yaml) {
             $this->changedFilesDetector->addCachableFile($file->getFilePath());
             return;
         }
 
-        $file->changeFileContent($this->yamlDumper->dump($newYaml, $indent));
+        // Re-dumped original as baseline: the diff shows only the rule's change,
+        // any extra reformatting is attributed to CodeFormatRule by the runner.
+        $file->changeOriginalContent(rtrim($this->yamlDumper->dump($yaml, $indent)) . "\n");
+        $file->changeFileContent(rtrim($this->yamlDumper->dump($newYaml, $indent)) . "\n");
     }
 
     /**

packages/fractor-yaml/tests/YamlProcessResult/Fixtures/rule-and-reformat.yaml.fixture

@@ -0,0 +1,13 @@
+# this comment is lost when the file is re-dumped
+Form:
+  renderingOptions:
+    translation:
+      translationFile:
+        10: 'EXT:form/Resources/Private/Language/locallang.xlf'
+        20: 'EXT:myextension/Resources/Private/Language/locallang.xlf'
+-----
+Form:
+  renderingOptions:
+    translation:
+      translationFiles:
+        20: 'EXT:myextension/Resources/Private/Language/locallang.xlf'

packages/fractor-yaml/tests/YamlProcessResult/Fixtures/rule-only.yaml.fixture

@@ -0,0 +1,12 @@
+Form:
+  renderingOptions:
+    translation:
+      translationFile:
+        10: 'EXT:form/Resources/Private/Language/locallang.xlf'
+        20: 'EXT:myextension/Resources/Private/Language/locallang.xlf'
+-----
+Form:
+  renderingOptions:
+    translation:
+      translationFiles:
+        20: 'EXT:myextension/Resources/Private/Language/locallang.xlf'

packages/fractor-yaml/tests/YamlProcessResult/Fixtures/untouched-with-comment.yaml.fixture

@@ -0,0 +1,4 @@
+# this comment survives because no rule rewrites the file
+Form:
+  renderingOptions:
+    skinning: true

packages/fractor-yaml/tests/YamlProcessResult/YamlProcessResultTest.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace a9f\FractorYaml\Tests\YamlProcessResult;
+
+use a9f\Fractor\Application\ValueObject\AppliedRule;
+use a9f\Fractor\Testing\PHPUnit\AbstractFractorTestCase;
+use a9f\FractorYaml\Tests\Fixtures\DummyYamlFractorRule;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+/**
+ * The YAML dumper cannot preserve comments, so the processor only re-dumps files
+ * a rule already rewrites — never for formatting alone. On such a file the rule
+ * stays attributed to itself, and any reformatting that rides along (indentation,
+ * lost comments) is additionally attributed to the virtual CodeFormatRule. A file
+ * no rule touches is left byte-exact, even when it carries comments.
+ */
+final class YamlProcessResultTest extends AbstractFractorTestCase
+{
+    /**
+     * @param list<string> $expectedAppliedRules
+     */
+    #[DataProvider('provideData')]
+    public function test(string $fixture, array $expectedAppliedRules): void
+    {
+        $fractorTestResult = $this->doTestFile(__DIR__ . '/Fixtures/' . $fixture);
+
+        self::assertSame($expectedAppliedRules, $fractorTestResult->getAppliedFractorRules());
+    }
+
+    /**
+     * @return \Iterator<string, array{string, list<string>}>
+     */
+    public static function provideData(): \Iterator
+    {
+        yield 'rule change on canonical input is attributed to the real rule' => [
+            'rule-only.yaml.fixture',
+            [DummyYamlFractorRule::class],
+        ];
+        yield 'reformatting that rides along a rule is also attributed to the code-format rule' => [
+            'rule-and-reformat.yaml.fixture',
+            [AppliedRule::CODE_FORMAT_RULE, DummyYamlFractorRule::class],
+        ];
+        yield 'a file no rule touches is left byte-exact' => ['untouched-with-comment.yaml.fixture', []];
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/fractor.php';
+    }
+}

packages/fractor-yaml/tests/YamlProcessResult/config/fractor.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+use a9f\Fractor\Configuration\FractorConfiguration;
+use a9f\FractorYaml\Tests\Fixtures\DummyYamlFractorRule;
+
+return FractorConfiguration::configure()
+    ->withRules([DummyYamlFractorRule::class]);