feat(tia): adds poc

src/Plugins/Tia/Fingerprint.php

@@ -0,0 +1,95 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pest\Plugins\Tia;
+
+/**
+ * Captures environmental inputs that, when changed, make the TIA graph stale.
+ *
+ * Any drift in PHP version, Composer lock, or Pest/PHPUnit config can change
+ * what a test actually exercises, so the graph must be rebuilt in those cases.
+ *
+ * @internal
+ */
+final readonly class Fingerprint
+{
+    // Bump this whenever the set of inputs or the hash algorithm changes, so
+    // older graphs are invalidated automatically.
+    private const int SCHEMA_VERSION = 2;
+
+    /**
+     * @param  non-empty-string  $projectRoot
+     */
+    public static function compute(string $projectRoot): array
+    {
+        return [
+            'schema' => self::SCHEMA_VERSION,
+            'php' => PHP_VERSION,
+            'pest' => self::readPestVersion($projectRoot),
+            'composer_lock' => self::hashIfExists($projectRoot.'/composer.lock'),
+            'phpunit_xml' => self::hashIfExists($projectRoot.'/phpunit.xml'),
+            'phpunit_xml_dist' => self::hashIfExists($projectRoot.'/phpunit.xml.dist'),
+            'pest_php' => self::hashIfExists($projectRoot.'/tests/Pest.php'),
+            // Pest's generated classes bake the code-generation logic in — if
+            // TestCaseFactory changes (new attribute, different method
+            // signature, etc.) every previously-recorded edge is stale.
+            // Hashing the factory sources makes path-repo / dev-main installs
+            // automatically rebuild their graphs when Pest itself is edited.
+            'pest_factory' => self::hashIfExists(__DIR__.'/../../Factories/TestCaseFactory.php'),
+            'pest_method_factory' => self::hashIfExists(__DIR__.'/../../Factories/TestCaseMethodFactory.php'),
+        ];
+    }
+
+    /**
+     * @param  array<string, mixed>  $a
+     * @param  array<string, mixed>  $b
+     */
+    public static function matches(array $a, array $b): bool
+    {
+        ksort($a);
+        ksort($b);
+
+        return $a === $b;
+    }
+
+    private static function hashIfExists(string $path): ?string
+    {
+        if (! is_file($path)) {
+            return null;
+        }
+
+        $hash = @hash_file('xxh128', $path);
+
+        return $hash === false ? null : $hash;
+    }
+
+    private static function readPestVersion(string $projectRoot): string
+    {
+        $installed = $projectRoot.'/vendor/composer/installed.json';
+
+        if (! is_file($installed)) {
+            return 'unknown';
+        }
+
+        $raw = @file_get_contents($installed);
+
+        if ($raw === false) {
+            return 'unknown';
+        }
+
+        $data = json_decode($raw, true);
+
+        if (! is_array($data) || ! isset($data['packages']) || ! is_array($data['packages'])) {
+            return 'unknown';
+        }
+
+        foreach ($data['packages'] as $package) {
+            if (is_array($package) && ($package['name'] ?? null) === 'pestphp/pest') {
+                return (string) ($package['version'] ?? 'unknown');
+            }
+        }
+
+        return 'unknown';
+    }
+}