feat(tia): support projects in git repository subdirectories (monorepos)

src/Plugins/Tia.php

@@ -15,7 +15,6 @@
 use Pest\Exceptions\TiaRequiresCommit;
 use Pest\Exceptions\TiaRequiresDefaultBranch;
 use Pest\Exceptions\TiaRequiresRemote;
-use Pest\Exceptions\TiaRequiresRepositoryRoot;
 use Pest\Panic;
 use Pest\Plugins\Concerns\HandleArguments;
 use Pest\Plugins\Tia\BaselineSync;
@@ -33,7 +32,6 @@
 use Pest\Plugins\Tia\TableExtractor;
 use Pest\Plugins\Tia\WatchPatterns;
 use Pest\Support\Container;
-use Pest\Support\Git;
 use Pest\Support\View;
 use Pest\TestCaseFilters\TiaTestCaseFilter;
 use Pest\TestSuite;
@@ -822,12 +820,6 @@ private function handleParent(array $arguments, string $projectRoot, bool $force
     {
         $this->watchPatterns->useDefaults($projectRoot);
 
-        $subdirectoryPrefix = $this->gitSubdirectoryPrefix($projectRoot);
-
-        if ($subdirectoryPrefix !== null) {
-            Panic::with(new TiaRequiresRepositoryRoot($subdirectoryPrefix));
-        }
-
         try {
             $this->resolveBranch($projectRoot);
         } catch (MissingDependency $missingGit) {
@@ -2154,19 +2146,14 @@ private function formatStructuralDrift(array $drift): string
         return implode(', ', array_keys($seen));
     }
 
-    private function gitSubdirectoryPrefix(string $projectRoot): ?string
-    {
-        return new Git($projectRoot)->subdirectoryPrefix();
-    }
-
     private function composerLockDelta(string $projectRoot, string $sha): string
     {
         $current = @file_get_contents($projectRoot.'/composer.lock');
         if ($current === false) {
             return '';
         }
 
-        $baseline = new Git($projectRoot)->show($sha, 'composer.lock');
+        $baseline = new ChangedFiles($projectRoot)->contentAtSha($sha, 'composer.lock');
 
         if ($baseline === null) {
             return '';

src/Plugins/Tia/BaselineSync.php

@@ -183,9 +183,9 @@ private function isCi(): bool
 
     private function detectGitHubRepo(string $projectRoot): ?string
     {
-        $gitConfig = $projectRoot.DIRECTORY_SEPARATOR.'.git'.DIRECTORY_SEPARATOR.'config';
+        $gitConfig = GitRepository::configPath($projectRoot);
 
-        if (! is_file($gitConfig)) {
+        if ($gitConfig === null) {
             return null;
         }
 

src/Plugins/Tia/ChangedFiles.php

@@ -14,9 +14,17 @@
 {
     private Git $git;
 
+    private string $repoPrefix;
+
     public function __construct(private string $projectRoot)
     {
         $this->git = new Git($projectRoot);
+        $this->repoPrefix = $this->detectRepoPrefix();
+    }
+
+    public function repoPrefix(): string
+    {
+        return $this->repoPrefix;
     }
 
     /**
@@ -158,9 +166,9 @@ private function filterBehaviourallyUnchanged(array $files, string $sha): array
         return $remaining;
     }
 
-    private function contentAtSha(string $sha, string $path): ?string
+    public function contentAtSha(string $sha, string $path): ?string
     {
-        return $this->git->show($sha, $path);
+        return $this->git->show($sha, $this->repoPrefix.$path);
     }
 
     /**
@@ -305,13 +313,15 @@ private function shaIsReachable(string $sha): bool
      */
     private function diffSinceSha(string $sha): array
     {
-        $output = $this->scan()->raw(['diff', '--name-only', '--no-renames', $sha.'..HEAD']);
+        $output = $this->scan()->raw(['diff', '--name-only', '-z', '--no-renames', $sha.'..HEAD']);
 
         if ($output === null) {
             throw new MissingDependency('Tia mode', 'git');
         }
 
-        return $this->splitLines($output);
+        $paths = explode("\x00", rtrim($output, "\x00"));
+
+        return $this->toProjectRelative(array_values(array_filter($paths, static fn (string $path): bool => $path !== '')));
     }
 
     /**
@@ -357,7 +367,7 @@ private function workingTreeChanges(): array
             $files[] = $path;
         }
 
-        return $files;
+        return $this->toProjectRelative($files);
     }
 
     public function currentSha(): ?string
@@ -373,6 +383,44 @@ public function currentSha(): ?string
         return $sha === '' ? null : $sha;
     }
 
+    /**
+     * @param  array<int, string>  $repoRelativePaths
+     * @return array<int, string>
+     */
+    private function toProjectRelative(array $repoRelativePaths): array
+    {
+        if ($this->repoPrefix === '') {
+            return $repoRelativePaths;
+        }
+
+        $projectRelative = [];
+
+        foreach ($repoRelativePaths as $path) {
+            if (str_starts_with($path, $this->repoPrefix)) {
+                $projectRelative[] = substr($path, strlen($this->repoPrefix));
+            }
+        }
+
+        return $projectRelative;
+    }
+
+    private function detectRepoPrefix(): string
+    {
+        static $cache = [];
+
+        if (isset($cache[$this->projectRoot])) {
+            return $cache[$this->projectRoot];
+        }
+
+        $prefix = $this->git->subdirectoryPrefix();
+
+        if ($prefix === null || $prefix === '') {
+            return $cache[$this->projectRoot] = '';
+        }
+
+        return $cache[$this->projectRoot] = $prefix.'/';
+    }
+
     /**
      * @return array<int, string>
      */

src/Plugins/Tia/Fingerprint.php

@@ -275,7 +275,7 @@ private static function isTrackedByGit(string $projectRoot, string $relativePath
             return $cache[$key];
         }
 
-        if (! is_dir($projectRoot.'/.git') && ! is_file($projectRoot.'/.git')) {
+        if (GitRepository::locate($projectRoot) === null) {
             return $cache[$key] = true;
         }
 

src/Plugins/Tia/GitRepository.php

@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pest\Plugins\Tia;
+
+/**
+ * Locates the git repository governing a path, which for projects living in
+ * a subdirectory of a monorepo sits in an ancestor directory rather than the
+ * project root itself. Paths are walked as strings, so callers pass
+ * canonical (realpath'd) roots.
+ *
+ * @internal
+ */
+final class GitRepository
+{
+    /**
+     * The nearest ancestor `.git` entry governing the given path — a
+     * directory for regular repositories, a file for worktrees and
+     * submodules — or `null` when the path is not inside a repository.
+     */
+    public static function locate(string $path): ?string
+    {
+        $dir = $path;
+
+        while (true) {
+            $dotGit = $dir.DIRECTORY_SEPARATOR.'.git';
+
+            if (is_dir($dotGit) || is_file($dotGit)) {
+                return $dotGit;
+            }
+
+            $parent = dirname($dir);
+
+            if ($parent === $dir) {
+                return null;
+            }
+
+            $dir = $parent;
+        }
+    }
+
+    /**
+     * The governing repository's config file, or `null` when there is none
+     * or it cannot be resolved by static inspection.
+     */
+    public static function configPath(string $path): ?string
+    {
+        $dotGit = self::locate($path);
+
+        if ($dotGit === null || ! is_dir($dotGit)) {
+            return null;
+        }
+
+        $config = $dotGit.DIRECTORY_SEPARATOR.'config';
+
+        return is_file($config) ? $config : null;
+    }
+
+    /**
+     * The project's path relative to the governing repository's root, with a
+     * trailing slash (`apps/api/`), or an empty string when the project is
+     * the repository root or sits outside any repository.
+     */
+    public static function subdirectoryPrefix(string $projectRoot): string
+    {
+        $dotGit = self::locate($projectRoot);
+
+        if ($dotGit === null) {
+            return '';
+        }
+
+        $repoRoot = dirname($dotGit);
+        $realRepoRoot = @realpath($repoRoot);
+        $realProjectRoot = @realpath($projectRoot);
+
+        if ($realRepoRoot === false || $realProjectRoot === false || $realRepoRoot === $realProjectRoot) {
+            return '';
+        }
+
+        $prefix = substr($realProjectRoot, strlen(rtrim($realRepoRoot, DIRECTORY_SEPARATOR)) + 1);
+
+        return str_replace(DIRECTORY_SEPARATOR, '/', rtrim($prefix, DIRECTORY_SEPARATOR)).'/';
+    }
+}

src/Plugins/Tia/Storage.php

@@ -85,6 +85,14 @@ private static function projectKey(string $projectRoot): string
     {
         $origin = self::originIdentity($projectRoot);
 
+        if ($origin !== null) {
+            $prefix = GitRepository::subdirectoryPrefix($projectRoot);
+
+            if ($prefix !== '') {
+                $origin .= '#'.$prefix;
+            }
+        }
+
         $realpath = @realpath($projectRoot);
         $input = $origin ?? ($realpath === false ? $projectRoot : $realpath);
 
@@ -117,9 +125,9 @@ private static function originIdentity(string $projectRoot): ?string
 
     private static function rawOriginUrl(string $projectRoot): ?string
     {
-        $config = $projectRoot.DIRECTORY_SEPARATOR.'.git'.DIRECTORY_SEPARATOR.'config';
+        $config = GitRepository::configPath($projectRoot);
 
-        if (! is_file($config)) {
+        if ($config === null) {
             return null;
         }
 

tests/Features/Tia/BranchShapes.php

@@ -155,16 +155,14 @@
         ->and($project->graph()['baselines']['master']['results'])->toHaveCount(Project::TOTAL_TESTS);
 })->skipOnWindows();
 
-test('a project below the git repository root refuses to run and writes nothing', function (array $arguments): void {
+test('a project below the git repository root runs from the subdirectory', function (array $arguments): void {
     $project = Project::make('master');
     $nested = $project->nested();
 
     $result = $project->pestIn($nested, '--tia', ...$arguments);
 
-    expect($result->exitCode)->toBe(1, $result->describe())
-        ->and($result->output)->toContain('Tia mode requires the git repository root')
-        ->and($project->path('.home/.pest'))->not->toBeDirectory()
-        ->and($nested.DIRECTORY_SEPARATOR.'.pest')->not->toBeDirectory();
+    expect($result->exitCode)->toBe(0, $result->describe())
+        ->and($result->tally())->toContain(Project::TOTAL_TESTS.' passed');
 })->with(Project::SEQUENTIAL_AND_PARALLEL)->skipOnWindows();
 
 test('a repository with no commits says so, and leaves plain runs alone', function (): void {