refactor: drop root object from origin and fingerprint

CHANGELOG.md

@@ -6,6 +6,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 
 ## [Unreleased]
 
+### Changed
+
+- `Origin` now accepts `$appDir` and `$vendorDir` parameters directly, instead of `Root` object. This makes
+  application detection more explicit and reliable, without depending on additional packages.
+- `Fingerprint` now accepts an `$appDir` parameter, instead of `Root` object. This makes relative path fingerprinting
+  more explicitly opt-in.
+
 ## [0.1.0] - 2026-10-05
 
 ### Added

docs/problems.md

@@ -70,6 +70,23 @@ followed by extension members in insertion order.
 
 The HTTP problem documents described below will also throw when attempting to overwrite `title` or `status`.
 
+## ProblemMap
+
+`Errata\ProblemMap` maps a class name to a factory `Closure(object): Problem`:
+
+```php
+use Errata\Problem;
+use Errata\ProblemMap;
+
+$map = new ProblemMap([
+    ValidationError::class => new ValidationProblemFactory(),
+]);
+```
+
+Lookup checks the exact class first, then parent classes nearest-first, then implemented interfaces, and returns
+the first factory found. When nothing matches, `get()` returns `null` and the transformer falls back to an
+`InternalServerError`.
+
 ## HTTP problems
 
 The `Errata\Http` namespace ships fixed-status problem documents. `Errata\Http\HttpProblem` is the abstract base;

docs/throwables.md

@@ -22,15 +22,16 @@ and an `ExtensionList` whose extensions enrich the resulting problem.
 
 ## ProblemMap
 
-`Errata\ProblemMap` maps a throwable class name to a factory `Closure(object): Problem`.
+`Errata\ProblemMap` maps a class name to a factory `Closure(object): Problem`. This can be used for throwables:
 
 ```php
 use Errata\Http\Client\UnprocessableContent;
 use Errata\ProblemMap;
 
 $map = new ProblemMap([
-    ValidationFailed::class => static fn(ValidationFailed $e): UnprocessableContent
-        => new UnprocessableContent(detail: $e->getMessage()),
+    ValidationFailed::class => static fn(ValidationFailed $e): UnprocessableContent => new UnprocessableContent(detail: $e->getMessage()),
+    // Or, if you prefer an object with __invoke:
+    ValidationFailed::class => new UnprocessableContentFactory(),
 ]);
 ```
 
@@ -98,17 +99,12 @@ Additional constructor options:
 - `Fingerprint` takes `algo`, which defaults to `xxh64` and accepts any `hash()` algorithm, and a `Root`. The hash
   input joins the throwable class, code, and the file path made relative to the application root, so fingerprints
   are stable across systems.
-- `Origin` and `Fingerprint` both take a `Root`.
+- `Origin` takes `appDir` and `vendorDir` to allow picking an application-specific origin by finding the first
+  `Location` that is inside the `appDir` and *not* inside the `vendorDir`.
+- `Fingerprint` takes `appDir` to make the file path relative for increased fingerprint stability.
 
 ### Trace locations
 
 `Errata\Trace\Location` represents one entry in a throwable's stack trace. A location list starts with the
 throwable's own file and line, followed by the trace frames, skipping entries without a file. Locations serialize
 to JSON as `"file:line"` strings.
-
-## Root
-
-`Errata\Root` identifies the application directory and the vendor directory beneath it. When no directory is
-given, it is detected from Composer. `isApp()` reports whether a path is inside the application but not the vendor
-tree, and `relative()` makes a path relative to the application root while leaving paths outside it untouched.
-`Origin` and `Fingerprint` use both.

src/Extension/Fingerprint.php

@@ -5,34 +5,50 @@
 namespace Errata\Extension;
 
 use Errata\Problem;
-use Errata\Root;
 use Override;
 use Throwable;
 
 use function hash;
+use function Psl\Filesystem\canonicalize;
+use function Psl\Str\Byte\after;
 use function Psl\Str\join;
 
+use const Psl\Filesystem\SEPARATOR;
+
 /**
  * @api
  */
 final readonly class Fingerprint implements Extension
 {
+    /** @var non-empty-string|null */
+    private ?string $appDir;
+
+    /**
+     * @param string|null $appDir
+     */
     public function __construct(
-        private Root $root = new Root(),
         /** @var non-empty-string */
         private string $key = 'fingerprint',
         /** @var non-empty-string */
         private string $algo = 'xxh64',
-    ) {}
+        ?string $appDir = null,
+    ) {
+        $this->appDir = $appDir ? canonicalize($appDir) : null;
+    }
 
     #[Override]
     public function extend(Problem $problem, Throwable $throwable): void
     {
+        $file = $throwable->getFile();
+
+        if ($this->appDir) {
+            $file = after($file, $this->appDir . SEPARATOR) ?? $file;
+        }
+
         $elements = [
             $throwable::class,
             (string) $throwable->getCode(),
-            // File path MUST be made relative for stability across systems.
-            $this->root->relative($throwable->getFile()),
+            $file,
         ];
 
         $problem->extend($this->key, hash($this->algo, join($elements, glue: '|')));

src/Extension/Origin.php

@@ -5,38 +5,73 @@
 namespace Errata\Extension;
 
 use Errata\Problem;
-use Errata\Root;
 use Errata\Trace\Location;
 use Override;
 use Throwable;
 
+use function Psl\Filesystem\canonicalize;
+use function Psl\Str\Byte\starts_with;
+
 /**
  * @api
  */
 final readonly class Origin implements Extension
 {
+    /** @var non-empty-string|null */
+    private ?string $appDir;
+
+    /** @var non-empty-string|null */
+    private ?string $vendorDir;
+
+    /**
+     * @param string|null $appDir
+     * @param string|null $vendorDir
+     */
     public function __construct(
-        private Root $root = new Root(),
         /** @var non-empty-string */
         private string $key = 'origin',
-    ) {}
+        ?string $appDir = null,
+        ?string $vendorDir = null,
+    ) {
+        $this->appDir = $appDir ? canonicalize($appDir) : null;
+        $this->vendorDir = $vendorDir ? canonicalize($vendorDir) : null;
+    }
 
     #[Override]
     public function extend(Problem $problem, Throwable $throwable): void
     {
-        $problem->extend($this->key, $this->findOrigin($throwable));
+        $origin = $this->findOrigin($throwable);
+
+        if ($this->appDir) {
+            $origin = $origin->withoutDirectory($this->appDir);
+        }
+
+        $problem->extend($this->key, $origin);
     }
 
     private function findOrigin(Throwable $throwable): Location
     {
         $locations = Location::trace($throwable);
 
         foreach ($locations as $location) {
-            if ($this->root->isApp($location->file)) {
+            if ($this->isApp($location)) {
                 return $location;
             }
         }
 
         return $locations[0] ?? new Location('(internal)');
     }
+
+    private function isApp(Location $location): bool
+    {
+        if ($this->appDir === null) {
+            return false;
+        }
+
+        if ($this->vendorDir && starts_with($location->file, $this->vendorDir)) {
+            return false;
+        }
+
+        return starts_with($location->file, $this->appDir);
+    }
 }

src/Problem.php

@@ -78,27 +78,13 @@ final public function extend(string $name, mixed $value): self
      **/
     final public function toArray(): array
     {
-        $members = [];
-
-        if ($this->type !== null) {
-            $members['type'] = $this->type;
-        }
-
-        if ($this->title !== null) {
-            $members['title'] = $this->title;
-        }
-
-        if ($this->detail !== null) {
-            $members['detail'] = $this->detail;
-        }
-
-        if ($this->status !== null) {
-            $members['status'] = $this->status;
-        }
-
-        if ($this->instance !== null) {
-            $members['instance'] = $this->instance;
-        }
+        $members = [
+            'type' => $this->type,
+            'title' => $this->title,
+            'detail' => $this->detail,
+            'status' => $this->status,
+            'instance' => $this->instance,
+        ];
 
         return filter_nulls($members + $this->extensions);
     }

src/ProblemMap.php

@@ -4,16 +4,14 @@
 
 namespace Errata;
 
-use Closure;
-
 use function class_implements;
 use function class_parents;
 
 /**
  * @api
  * @template T of object
  * @template Tk of class-string
- * @template Tv of Closure(T):Problem
+ * @template Tv of callable(T):Problem
  */
 final readonly class ProblemMap
 {
@@ -23,9 +21,10 @@ public function __construct(
     ) {}
 
     /**
+     * @param T $instance
      * @return Tv|null
      */
-    public function get(object $instance): ?Closure
+    public function get(object $instance): ?callable
     {
         $classes = [
             $instance::class,

src/Trace/Location.php

@@ -9,6 +9,11 @@
 use Stringable;
 use Throwable;
 
+use function Psl\Str\Byte\after;
+use function Psl\Str\Byte\starts_with;
+
+use const Psl\Filesystem\SEPARATOR;
+
 /**
  * @internal
  */
@@ -47,6 +52,20 @@ public function __construct(
         public int $line = 0,
     ) {}
 
+    /**
+     * @param non-empty-string $dir
+     */
+    public function withoutDirectory(string $dir): self
+    {
+        if (!starts_with($this->file, $dir)) {
+            return $this;
+        }
+
+        // @mago-expect analysis:possibly-invalid-argument
+        // @mago-expect analysis:possibly-null-argument
+        return new self(after($this->file, $dir . SEPARATOR), $this->line);
+    }
+
     public function toString(): string
     {
         if ($this->line < 1) {