fix: keep the booking room assignment when restoring an edit draft

src/Service/BookingEditDraftMerger.php

@@ -18,8 +18,9 @@ use App\Form\Model\ParticipantDto;
  *
  * Service selections are gated by travel-level mutability flags (additionalServicesMutable,
  * transportationServicesMutable, pickupsMutable). Insurance is always applied regardless
- * of mutability. Merge strategy (only apply if resolves to a valid service) is used for
- * single-select fields; overwrite strategy is used for multi-select and boolean fields.
+ * of mutability. Merge strategy (only apply if it resolves against the travel data) is used
+ * for single-select fields, room assignment included; overwrite strategy is used for
+ * multi-select, boolean and free-text fields.
  */
 class BookingEditDraftMerger
 {
@@ -52,7 +53,7 @@ class BookingEditDraftMerger
 
         // Room assignment
         if (true === isset($data['roomAssignment']) && true === is_array($data['roomAssignment'])) {
-            $this->applyRoomAssignment($participant, $data['roomAssignment']);
+            $this->applyRoomAssignment($participant, $data['roomAssignment'], $travel);
         }
 
         // License plate
@@ -156,12 +157,27 @@ class BookingEditDraftMerger
         }
     }
 
-    /** @param array<string, mixed> $data */
-    private function applyRoomAssignment(ParticipantDto $participant, array $data): void
+    /**
+     * Applies the drafted room assignment to the participant.
+     *
+     * The room id uses the same merge strategy as single-select services: it is only
+     * applied when it resolves to a room of the current travel. A draft may therefore move
+     * a participant to another room, but never unassign one. Edit mode renders the room as
+     * static text and never submits assignedRoomId, so a null in the draft is only ever an
+     * artefact of a snapshot taken before BusPro reported the assignment - replaying it
+     * would drop the participant's room, both in the UI and in the outbound zuordnung.
+     *
+     * remarksRoom keeps overwrite semantics: it is free text the user can deliberately clear.
+     *
+     * @param array<string, mixed> $data
+     */
+    private function applyRoomAssignment(ParticipantDto $participant, array $data, Travel $travel): void
     {
-        if (true === array_key_exists('assignedRoomId', $data)) {
-            $participant->assignedRoomId = $data['assignedRoomId'];
+        $assignedRoomId = $data['assignedRoomId'] ?? null;
+        if (null !== $assignedRoomId && null !== $travel->getRoomById((int) $assignedRoomId)) {
+            $participant->assignedRoomId = (int) $assignedRoomId;
         }
+
         if (true === array_key_exists('remarksRoom', $data)) {
             $participant->remarksRoom = $data['remarksRoom'];
         }

tests/Service/BookingEditDraftMergerRoomAssignmentTest.php

@@ -0,0 +1,115 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Service;
+
+use App\BusProNet\Model\Room;
+use App\BusProNet\Model\Travel;
+use App\Form\Model\BookingDto;
+use App\Form\Model\ParticipantDto;
+use App\Service\BookingEditDraftMerger;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Tests that draft restoration never unassigns a room.
+ *
+ * Edit mode renders the room as static text and never submits assignedRoomId, so a null in
+ * the draft payload is always an artefact of a snapshot taken before BusPro reported the
+ * assignment - typically for seats added to a group booking shortly before the draft was
+ * saved. Replaying such a null would strip the room from the UI and from the outbound
+ * zuordnung, so the room id uses the same merge strategy as single-select services.
+ */
+class BookingEditDraftMergerRoomAssignmentTest extends TestCase
+{
+    private BookingEditDraftMerger $merger;
+
+    protected function setUp(): void
+    {
+        $this->merger = new BookingEditDraftMerger();
+    }
+
+    public function testDraftDoesNotUnassignRoomWhenDraftValueIsNull(): void
+    {
+        $participant = new ParticipantDto();
+        $participant->mutable = true;
+        $participant->assignedRoomId = 74;
+
+        $travel = $this->createTravel([74 => $this->createRoom(74, 'Bett im Mehrbettzimmer')]);
+
+        $this->apply($travel, $participant, ['assignedRoomId' => null]);
+
+        $this->assertSame(74, $participant->assignedRoomId);
+    }
+
+    public function testDraftAppliesRoomThatResolvesAgainstTravel(): void
+    {
+        $participant = new ParticipantDto();
+        $participant->mutable = true;
+        $participant->assignedRoomId = 74;
+
+        $travel = $this->createTravel([
+            74 => $this->createRoom(74, 'Bett im Mehrbettzimmer'),
+            75 => $this->createRoom(75, 'Doppelzimmer'),
+        ]);
+
+        $this->apply($travel, $participant, ['assignedRoomId' => 75]);
+
+        $this->assertSame(75, $participant->assignedRoomId);
+    }
+
+    public function testDraftSkipsRoomThatIsUnknownToTravel(): void
+    {
+        $participant = new ParticipantDto();
+        $participant->mutable = true;
+        $participant->assignedRoomId = 74;
+
+        $travel = $this->createTravel([74 => $this->createRoom(74, 'Bett im Mehrbettzimmer')]);
+
+        $this->apply($travel, $participant, ['assignedRoomId' => 999]);
+
+        $this->assertSame(74, $participant->assignedRoomId);
+    }
+
+    public function testDraftClearsRoomRemarks(): void
+    {
+        $participant = new ParticipantDto();
+        $participant->mutable = true;
+        $participant->assignedRoomId = 74;
+        $participant->remarksRoom = 'Bitte mit Lisa';
+
+        $travel = $this->createTravel([74 => $this->createRoom(74, 'Bett im Mehrbettzimmer')]);
+
+        $this->apply($travel, $participant, ['assignedRoomId' => null, 'remarksRoom' => null]);
+
+        $this->assertNull($participant->remarksRoom);
+        $this->assertSame(74, $participant->assignedRoomId);
+    }
+
+    /** @param array<string, mixed> $roomAssignment */
+    private function apply(Travel $travel, ParticipantDto $participant, array $roomAssignment): void
+    {
+        $dto = new BookingDto($travel, 1);
+        $dto->participants = [1 => $participant];
+
+        $this->merger->apply($dto, 1, $participant, ['roomAssignment' => $roomAssignment], $travel);
+    }
+
+    /** @param array<int, Room> $rooms */
+    private function createTravel(array $rooms): Travel
+    {
+        $travel = new Travel();
+        $travel->rooms = $rooms;
+
+        return $travel;
+    }
+
+    private function createRoom(int $id, string $label): Room
+    {
+        $room = new Room();
+        $room->id = $id;
+        $room->label = $label;
+
+        return $room;
+    }
+}