chore: fixes tia when not running on root

src/Configuration.php

@@ -122,9 +122,9 @@ final readonly class Configuration
     /**
      * Gets the evals configuration.
      */
-    public function evals(): Evals\Configuration
+    public function evals(): Evals\Configuration // @phpstan-ignore-line
     {
-        return new Evals\Configuration;
+        return new Evals\Configuration; // @phpstan-ignore-line
     }
 
     /**

src/Exceptions/TiaRequiresRepositoryRoot.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pest\Exceptions;
+
+use NunoMaduro\Collision\Contracts\RenderlessEditor;
+use NunoMaduro\Collision\Contracts\RenderlessTrace;
+use Pest\Contracts\Panicable;
+use RuntimeException;
+use Symfony\Component\Console\Exception\ExceptionInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+/**
+ * @internal
+ */
+final class TiaRequiresRepositoryRoot extends RuntimeException implements ExceptionInterface, Panicable, RenderlessEditor, RenderlessTrace
+{
+    public function __construct(private readonly string $subdirectoryPrefix)
+    {
+        parent::__construct(sprintf(
+            'Tia mode requires the project root to be the git repository root, but it sits in the subdirectory [%s] of a larger repo.',
+            $this->subdirectoryPrefix,
+        ));
+    }
+
+    public function render(OutputInterface $output): void
+    {
+        $output->writeln([
+            '',
+            '  <fg=white;options=bold;bg=red> ERROR </> Tia mode requires the git repository root.',
+            '',
+            sprintf('  This project sits in a subdirectory of a larger repo <fg=yellow>%s</>.', $this->subdirectoryPrefix),
+            '',
+            '  Give the project its own git repository to use Tia.',
+            '',
+        ]);
+    }
+
+    public function exitCode(): int
+    {
+        return 1;
+    }
+}

src/Expectations/HigherOrderExpectation.php

@@ -112,7 +112,7 @@ final class HigherOrderExpectation
      * Dynamically calls methods on the class with the given arguments.
      *
      * @param  array<int, mixed>  $arguments
-     * @return self<TOriginalValue, mixed>|self<TOriginalValue, TValue>
+     * @return self<TOriginalValue, mixed>
      */
     public function __call(string $name, array $arguments): self
     {
@@ -127,7 +127,7 @@ final class HigherOrderExpectation
     /**
      * Accesses properties in the value or in the expectation.
      *
-     * @return self<TOriginalValue, mixed>|self<TOriginalValue, TValue>
+     * @return self<TOriginalValue, mixed>
      */
     public function __get(string $name): self
     {

src/Plugins/Tia.php

@@ -9,6 +9,7 @@ use Pest\Contracts\Plugins\AddsOutput;
 use Pest\Contracts\Plugins\HandlesArguments;
 use Pest\Contracts\Plugins\Terminable;
 use Pest\Exceptions\NoAffectedTestsFound;
+use Pest\Exceptions\TiaRequiresRepositoryRoot;
 use Pest\Panic;
 use Pest\Plugins\Concerns\HandleArguments;
 use Pest\Plugins\Tia\BaselineSync;
@@ -627,6 +628,13 @@ final class Tia implements AddsOutput, HandlesArguments, Terminable
     private function handleParent(array $arguments, string $projectRoot, bool $forceRebuild): array
     {
         $this->watchPatterns->useDefaults($projectRoot);
+
+        $subdirectoryPrefix = $this->gitSubdirectoryPrefix($projectRoot);
+
+        if ($subdirectoryPrefix !== null) {
+            Panic::with(new TiaRequiresRepositoryRoot($subdirectoryPrefix));
+        }
+
         $this->branch = new ChangedFiles($projectRoot)->currentBranch() ?? 'main';
 
         $fingerprint = Fingerprint::compute($projectRoot);
@@ -1643,6 +1651,27 @@ final class Tia implements AddsOutput, HandlesArguments, Terminable
         return implode(', ', array_keys($seen));
     }
 
+    /**
+     * The path from the git repository root down to $projectRoot (e.g.
+     * `laravel-app`) when the project is nested inside a larger repo, or `null`
+     * when the project root is itself the repo root (or git is unavailable).
+     * TIA requires the two to coincide: git reports and addresses paths
+     * relative to the repo root, while the dependency graph is project-relative.
+     */
+    private function gitSubdirectoryPrefix(string $projectRoot): ?string
+    {
+        $process = new Process(['git', 'rev-parse', '--show-prefix'], $projectRoot);
+        $process->run();
+
+        if (! $process->isSuccessful()) {
+            return null;
+        }
+
+        $prefix = trim($process->getOutput());
+
+        return $prefix === '' ? null : rtrim(str_replace(DIRECTORY_SEPARATOR, '/', $prefix), '/');
+    }
+
     private function composerLockDelta(string $projectRoot, string $sha): string
     {
         $current = @file_get_contents($projectRoot.'/composer.lock');