[TASK] Attribute CodeFormatRule to reformatted composer.json files

- Re-print composer.json on every run so a formatting-only change (indentation)
  is reported instead of applied silently; the runner attributes it to the
  virtual CodeFormatRule
- Keep a real rule attributed to itself; JSON has no comments, so the re-print
  round-trip preserves content
- Cover the behaviour with a ComposerJsonProcessResult test (rule change,
  pure reformat, and an already-formatted no-op)

Author: chrissonntag

packages/fractor-composer-json/src/ComposerJsonFileProcessor.php

@@ -36,23 +36,28 @@ public function canHandle(File $file): bool
 
     public function handle(File $file, iterable $appliedRules): void
     {
-        $fileHasChanged = \false;
+        $rawContent = $file->getContent();
         $composerJson = $this->composerJsonFactory->createFromFile($file);
-        $oldComposerJson = $this->composerJsonFactory->createFromFile($file);
 
         foreach ($appliedRules as $rule) {
+            $beforeArray = $composerJson->getJsonArray();
             $rule->refactor($composerJson);
 
-            if ($oldComposerJson->getJsonArray() !== $composerJson->getJsonArray()) {
-                $file->changeFileContent($this->composerJsonPrinter->printToString($this->indent, $composerJson));
+            if ($beforeArray !== $composerJson->getJsonArray()) {
                 $file->addAppliedRule(AppliedRule::fromRule($rule));
-                $fileHasChanged = \true;
             }
         }
 
-        if (! $fileHasChanged) {
+        // Always re-print: a formatting-only change (indentation) is then
+        // attributed to CodeFormatRule by the runner rather than applied silently.
+        $newContent = rtrim($this->composerJsonPrinter->printToString($this->indent, $composerJson)) . "\n";
+
+        if ($newContent === $rawContent) {
             $this->changedFilesDetector->addCachableFile($file->getFilePath());
+            return;
         }
+
+        $file->changeFileContent($newContent);
     }
 
     public function allowedFileExtensions(): array

packages/fractor-composer-json/tests/ComposerJsonProcessResult/ComposerJsonProcessResultTest.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace a9f\FractorComposerJson\Tests\ComposerJsonProcessResult;
+
+use a9f\Fractor\Application\ValueObject\AppliedRule;
+use a9f\Fractor\Testing\PHPUnit\AbstractFractorTestCase;
+use a9f\FractorComposerJson\RemovePackageComposerJsonFractor;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+/**
+ * The composer.json processor re-prints files it touches, so a formatting-only
+ * change (indentation) must be attributed to the virtual CodeFormatRule — so a
+ * re-indentation is reported rather than applied silently — while a real
+ * transformation stays attributed to its own rule.
+ */
+final class ComposerJsonProcessResultTest 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 is attributed to the real rule' => [
+            'rule-change/composer.json.fixture',
+            [RemovePackageComposerJsonFractor::class],
+        ];
+        yield 'pure reformat is attributed to the virtual code-format rule' => [
+            'reformatting/composer.json.fixture',
+            [AppliedRule::CODE_FORMAT_RULE],
+        ];
+        yield 'already formatted file reports no change' => ['already-formatted/composer.json.fixture', []];
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/fractor.php';
+    }
+}

packages/fractor-composer-json/tests/ComposerJsonProcessResult/Fixtures/already-formatted/composer.json.fixture

@@ -0,0 +1,6 @@
+{
+    "name": "acme/demo",
+    "require": {
+        "vendor1/keep": "^2.0"
+    }
+}

packages/fractor-composer-json/tests/ComposerJsonProcessResult/Fixtures/reformatting/composer.json.fixture

@@ -0,0 +1,13 @@
+{
+  "name": "acme/demo",
+  "require": {
+    "vendor1/keep": "^2.0"
+  }
+}
+-----
+{
+    "name": "acme/demo",
+    "require": {
+        "vendor1/keep": "^2.0"
+    }
+}

packages/fractor-composer-json/tests/ComposerJsonProcessResult/Fixtures/rule-change/composer.json.fixture

@@ -0,0 +1,12 @@
+{
+    "require": {
+        "vendor1/legacy": "^1.0",
+        "vendor1/keep": "^2.0"
+    }
+}
+-----
+{
+    "require": {
+        "vendor1/keep": "^2.0"
+    }
+}

packages/fractor-composer-json/tests/ComposerJsonProcessResult/config/fractor.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+use a9f\Fractor\Configuration\FractorConfiguration;
+use a9f\FractorComposerJson\RemovePackageComposerJsonFractor;
+
+return FractorConfiguration::configure()
+    ->import(__DIR__ . '/../../../config/application.php')
+    ->withConfiguredRule(RemovePackageComposerJsonFractor::class, ['vendor1/legacy']);