feat: add the product code to the travel export

docs/api-consumer-guide.md

@@ -172,6 +172,7 @@ an error: it returns `200` with an empty `data` array and the usual `meta`.
     {
       "busProId": 12794,
       "code": "PCJSER261226",
+      "productCode": "PCJSER",
       "product": "Semesterende - Portes du Soleil - Joliment",
       "dateFrom": "2026-12-26",
       "dateTo": "2026-12-30",
@@ -212,6 +213,11 @@ an error: it returns `200` with an empty `data` array and the usual `meta`.
 is always an int and never null; `hotel` is always an object and never null; `pickups` is always an array, possibly
 empty, never null.
 
+**`productCode`** is the code of the travel (product) the date belongs to, e.g. `DKIWE`. Key on it to
+recognise dates of the same product. Do not derive it from the date `code` by cutting off the date: some
+products run dates under a different code (`DWWMP` runs `DWWMW…`), and group travels carry each group's own
+code on the date. It is `null` for the few travels that have no code upstream.
+
 **`meta` describes the whole export, not the page.** `total`, `totalPages`, `skipped`, `pickupsWithoutMasterData`,
 `sourceGeneratedAt` and `generatedAt` are identical on every page, so you can read them once on page 1 and decide whether to walk the
 rest. `total` is the row count **after** skips, and `totalPages` is `ceil(total / perPage)`.

src/Service/TravelExportBuilder.php

@@ -157,9 +157,14 @@ class TravelExportBuilder
             $pickupsWithoutMasterData,
         );
 
+        // The product a date belongs to, from the enclosing <reise>. Not derivable from the
+        // date code: DWWMP runs dates coded DWWMW…, and group travels carry each group's code.
+        $productNode = $node->getNode(0)?->parentNode;
+
         $travel = [
             'busProId' => $travelId,
             'code' => $node->attr('code'),
+            'productCode' => $productNode instanceof \DOMElement ? $this->trimOrNull($productNode->getAttribute('code')) : null,
             'product' => $this->trimOrNull($this->getStringOrNullValue($node->filterXPath('.//text'))),
             'dateFrom' => $dateFrom->format('Y-m-d'),
             'dateTo' => $dateTo->format('Y-m-d'),

tests/Service/TravelExportBuilderTest.php

@@ -42,6 +42,7 @@ class TravelExportBuilderTest extends TestCase
         self::assertSame(900, $row['busProId']);
         self::assertIsInt($row['busProId']);
         self::assertSame('SBW261226', $row['code']);
+        self::assertSame('SBW', $row['productCode']);
         self::assertSame('Semesterende - Portes du Soleil', $row['product'], 'the product label is trimmed');
         self::assertSame('2026-12-26', $row['dateFrom']);
         self::assertSame('2026-12-30', $row['dateTo']);
@@ -56,6 +57,21 @@ class TravelExportBuilderTest extends TestCase
         ], $row['hotel']);
     }
 
+    public function testCarriesTheProductCodeOfTheEnclosingTravelRatherThanTheDateCode(): void
+    {
+        $rows = $this->build('<?xml version="1.0"?><reisen><reise code="DWWMP "><termin idbuspro="1" termin="01.01.2027" bis="02.01.2027" code="DWWMW010127"><hotel idbuspro="1"/></termin></reise></reisen>')->rows;
+
+        self::assertSame('DWWMP', $rows[0]['productCode'], 'taken from <reise>, trimmed');
+        self::assertSame('DWWMW010127', $rows[0]['code']);
+    }
+
+    public function testTheProductCodeIsNullWhenTheTravelCarriesNone(): void
+    {
+        $rows = $this->build('<?xml version="1.0"?><reisen><reise code=""><termin idbuspro="1" termin="01.01.2027" bis="02.01.2027" code="SCE010127"><hotel idbuspro="1"/></termin></reise></reisen>')->rows;
+
+        self::assertNull($rows[0]['productCode']);
+    }
+
     public function testResolvesBothZeitShapesAndRollsAnOvernightPickupOntoTheNextDay(): void
     {
         $pickups = array_column($this->rowFor('900-1')['pickups'], null, 'busProId');