add --staged flag

app/Commands/DefaultCommand.php

@@ -42,6 +42,7 @@ protected function configure()
                     new InputOption('bail', '', InputOption::VALUE_NONE, 'Test for code style errors without fixing them and stop on first error'),
                     new InputOption('repair', '', InputOption::VALUE_NONE, 'Fix code style errors but exit with status 1 if there were any changes made'),
                     new InputOption('dirty', '', InputOption::VALUE_NONE, 'Only fix files that have uncommitted changes'),
+                    new InputOption('staged', 's', InputOption::VALUE_NONE, 'Only fix files that have staged changes'),
                     new InputOption('format', '', InputOption::VALUE_REQUIRED, 'The output format that should be used'),
                     new InputOption('cache-file', '', InputArgument::OPTIONAL, 'The path to the cache file'),
                 ]

app/Contracts/PathsRepository.php

@@ -10,4 +10,12 @@ interface PathsRepository
      * @return array<int, string>
      */
     public function dirty();
+
+
+    /**
+     * Determine the "staged" files.
+     *
+     * @return array<int, string>
+     */
+    public function staged();
 }

app/Project.php

@@ -18,6 +18,10 @@ public static function paths($input)
             return static::resolveDirtyPaths();
         }
 
+        if ($input->getOption('staged')) {
+           return static::resolveStagedPaths();
+        }
+
         return $input->getArgument('path');
     }
 
@@ -46,4 +50,20 @@ public static function resolveDirtyPaths()
 
         return $files;
     }
+
+    /**
+     * Resolves the staged paths, if any.
+     *
+     * @return array<int, string>
+     */
+    public static function resolveStagedPaths()
+    {
+        $files = app(PathsRepository::class)->staged();
+
+        if (empty($files)) {
+            abort(0, 'No staged files found.');
+        }
+
+        return $files;
+    }
 }

app/Repositories/GitPathsRepository.php

@@ -60,4 +60,36 @@ public function dirty()
 
         return array_values(array_intersect($files, $dirtyFiles));
     }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function staged()
+    {
+        $process = tap(new Process(['git', 'diff', '--cached', '--name-only', '--diff-filter=ACM', '--', '**.php']))->run();
+
+       if (! $process->isSuccessful()) {
+            abort(1, 'The [--staged] option is only available when using Git.');
+       }
+
+       $stagedFiles = collect(preg_split('/\R+/', $process->getOutput(), flags: PREG_SPLIT_NO_EMPTY))
+            ->map(function ($file) {
+                if (PHP_OS_FAMILY === 'Windows') {
+                    $file = str_replace('/', DIRECTORY_SEPARATOR, $file);
+                }
+
+                return $this->path . DIRECTORY_SEPARATOR . $file;
+            })
+            ->values()
+            ->all();
+
+       $files = array_values(array_map(function ($splFile) {
+            return $splFile->getPathname();
+        }, iterator_to_array(ConfigurationFactory::finder()
+            ->in($this->path)
+            ->files()
+        )));
+
+        return array_values(array_intersect($files, $stagedFiles));
+    }
 }

tests/Feature/StagedTest.php

@@ -0,0 +1,63 @@
+<?php
+
+use App\Contracts\PathsRepository;
+
+it('determines staged files', function () {
+    $paths = Mockery::mock(PathsRepository::class);
+
+    $paths
+        ->shouldReceive('staged')
+        ->once()
+        ->andReturn([
+           base_path('tests/Fixtures/without-issues-laravel/file.php'),
+        ]);
+
+    $this->swap(PathsRepository::class, $paths);
+
+    [$statusCode, $output] = run('default', ['--staged' => true]);
+
+    expect($statusCode)->toBe(0)
+        ->and($output)
+        ->toContain('── Laravel', ' 1 file');
+});
+
+it('ignores the path argument', function () {
+    $paths = Mockery::mock(PathsRepository::class);
+
+    $paths
+        ->shouldReceive('staged')
+        ->once()
+        ->andReturn([
+            base_path('tests/Fixtures/without-issues-laravel/file.php'),
+        ]);
+
+    $this->swap(PathsRepository::class, $paths);
+
+    [$statusCode, $output] = run('default', [
+        '-s' => true,
+        'path' => base_path(),
+    ]);
+
+    expect($statusCode)->toBe(0)
+        ->and($output)
+        ->toContain('── Laravel', ' 1 file');
+});
+
+it('does not abort when there are no staged files', function () {
+    $paths = Mockery::mock(PathsRepository::class);
+
+    $paths
+        ->shouldReceive('staged')
+        ->once()
+        ->andReturn([]);
+
+    $this->swap(PathsRepository::class, $paths);
+
+    [$statusCode, $output] = run('default', [
+        '--staged' => true,
+    ]);
+
+    expect($statusCode)->toBe(0)
+        ->and($output)
+        ->toContain('── Laravel', ' 0 files');
+});