fix(mobile): editing a bus, car, taxi or ferry on the phone keeps its price (#2233)

Editing a transport without metadata of its own (bus, car, taxi, ferry
without a transit itinerary) in the phone sheet wiped the expense price
shown on the booking card. The phone built the payload with
emptyMetadataAsNull and sent metadata: null, which the reservations
service reads as "clear the column", so keepMirroredPrice had nothing to
carry price and priceCurrency into. The desktop and both booking forms
send an empty object, which keeps the price.

The option only existed to keep the phone's null, so it is gone and both
views now send the rebuilt metadata object as is.

Red test: FE-MOB-TRFRM-060 in
client/tests/unit/mobile/trip/MTransportFormSheet.test.tsx failed with
"AssertionError: expected null to deeply equal {}".
RESV-SVC-043 in server/tests/unit/nest/reservations.service.test.ts shows
the server side: {} keeps the stored price, null drops it.

Changed assertions (they asserted the null):
- MTransportFormSheet.test.tsx FE-MOB-TRFRM-006: payload metadata null
  is now {}.
- MTransportFormSheet.test.tsx FE-MOB-TRFRM-011: metadata toBeNull is now
  toEqual({}).
- MTransportFormSheet.test.tsx FE-MOB-TRFRM-027: metadata toBeNull is now
  toEqual({}).
- transportEndpoints.test.ts FE-PLANNER-TRANSPORTEP-014: phone metadata
  toBeNull is now toEqual({}) (title updated to match), and the
  emptyMetadataAsNull field is dropped from DESKTOP_SAVE and PHONE_SAVE.
- useTransportForm.test.ts FE-PLANNER-TRANSPORTFORM-007: metadata: null
  is now metadata: {}.

client/src/components/Planner/TransportModal.tsx

@@ -137,7 +137,7 @@ export function TransportModal({ isOpen, onClose, onSave, reservation, days, sel
     setIsSaving(true)
     try {
       const saved = await onSave(payload(days, {
-        reservation, prefill, budgetEnabled: isBudgetEnabled, anchorOnStations: false, emptyMetadataAsNull: false, url: form.url,
+        reservation, prefill, budgetEnabled: isBudgetEnabled, anchorOnStations: false, url: form.url,
       }))
       // Persist the traveler assignment once we have the reservation id (create → save
       // result, edit → existing reservation), and only when it actually changed (#1517).

client/src/components/Planner/transportEndpoints.test.ts

@@ -82,7 +82,6 @@ const DESKTOP_SAVE: TransportPayloadOptions = {
   prefill: null,
   budgetEnabled: false,
   anchorOnStations: false,
-  emptyMetadataAsNull: false,
   url: '',
 };
 const PHONE_SAVE: TransportPayloadOptions = {
@@ -90,7 +89,6 @@ const PHONE_SAVE: TransportPayloadOptions = {
   prefill: null,
   budgetEnabled: false,
   anchorOnStations: true,
-  emptyMetadataAsNull: true,
 };
 
 describe('transport types and endpoints', () => {
@@ -392,10 +390,10 @@ describe('buildTransportPayload', () => {
     });
   });
 
-  it('FE-PLANNER-TRANSPORTEP-014: the phone sends no url and an empty metadata as null; a url is sent when given', () => {
+  it('FE-PLANNER-TRANSPORTEP-014: the phone sends no url and an empty metadata as an empty object; a url is sent when given', () => {
     const phone = buildTransportPayload(draft(), days, PHONE_SAVE);
     expect(phone).not.toHaveProperty('url');
-    expect(phone.metadata).toBeNull();
+    expect(phone.metadata).toEqual({});
     expect(buildTransportPayload(draft(), days, { ...DESKTOP_SAVE, url: 'https://x.test' }).url).toBe('https://x.test');
   });
 

client/src/components/Planner/transportEndpoints.ts

@@ -497,8 +497,6 @@ export interface TransportPayloadOptions {
    * first and last rows.
    */
   anchorOnStations: boolean;
-  /** The phone sends a booking without metadata as null; the desktop sends an empty object (#2233). */
-  emptyMetadataAsNull: boolean;
   /** The desktop's link field; the phone has none and sends no url. */
   url?: string;
 }
@@ -731,7 +729,9 @@ export function buildTransportPayload(
     confirmation_number: form.confirmation_number || null,
     notes: form.notes || null,
     ...(opts.url !== undefined ? { url: opts.url || null } : {}),
-    metadata: opts.emptyMetadataAsNull && Object.keys(metadata).length === 0 ? null : metadata,
+    // Always an object, never null: the server reads null as "clear the column" and
+    // would drop the expense price mirrored into metadata (#2233).
+    metadata,
     endpoints,
     needs_review: false,
   };

client/src/components/Planner/useTransportForm.test.ts

@@ -150,9 +150,8 @@ describe('useTransportForm', () => {
       prefill: null,
       budgetEnabled: false,
       anchorOnStations: true,
-      emptyMetadataAsNull: true,
     });
-    expect(payload).toMatchObject({ title: 'Coach', type: 'bus', day_id: 1, metadata: null });
+    expect(payload).toMatchObject({ title: 'Coach', type: 'bus', day_id: 1, metadata: {} });
     expect(payload.endpoints).toEqual([
       expect.objectContaining({ role: 'to', name: 'B', sequence: 1, local_date: '2026-05-01' }),
     ]);

client/src/mobile/screens/trip/sheets/MTransportFormSheet.tsx

@@ -128,7 +128,7 @@ export default function MTransportFormSheet({ planner, onOpenExpense }: MTranspo
     setIsSaving(true)
     try {
       const saved = await saveTransport(buildPayload(days, {
-        reservation: res, prefill, budgetEnabled: isBudgetEnabled, anchorOnStations: true, emptyMetadataAsNull: true,
+        reservation: res, prefill, budgetEnabled: isBudgetEnabled, anchorOnStations: true,
       }))
       // Persist the traveler assignment once we have the reservation id (from the
       // save result on create, or the edited reservation) — only when it changed.

client/tests/unit/mobile/trip/MTransportFormSheet.test.tsx

@@ -248,7 +248,7 @@ describe('MTransportFormSheet', () => {
       location: null,
       confirmation_number: 'BUS-4711',
       notes: 'Seat 4 reserved',
-      metadata: null,
+      metadata: {},
       endpoints: [
         { role: 'from', sequence: 0, name: 'Osaka Station', code: null, lat: 34.7, lng: 135.5, timezone: null, local_date: '2026-05-01', local_time: '08:15' },
         { role: 'to', sequence: 1, name: 'Kyoto Station', code: null, lat: 34.98, lng: 135.75, timezone: null, local_date: '2026-05-02', local_time: '11:00' },
@@ -395,7 +395,7 @@ describe('MTransportFormSheet', () => {
     await submit()
 
     const payload = handleSaveTransport.mock.calls[0][0]
-    expect(payload.metadata).toBeNull()
+    expect(payload.metadata).toEqual({})
     expect(payload.endpoints).toEqual([])
     expect(payload.day_id).toBeNull()
   })
@@ -791,7 +791,7 @@ describe('MTransportFormSheet', () => {
 
     await submit('common.update')
     const payload = handleSaveTransport.mock.calls[0][0]
-    expect(payload.metadata).toBeNull()
+    expect(payload.metadata).toEqual({})
     expect(payload.endpoints).toEqual([
       expect.objectContaining({ role: 'from', name: 'Osaka Station' }),
       expect.objectContaining({ role: 'to', sequence: 1, name: 'Nara Station' }),
@@ -1142,4 +1142,19 @@ describe('MTransportFormSheet', () => {
     expect(handleSaveTransport).toHaveBeenCalled()
     expect(addFile).not.toHaveBeenCalled()
   })
+
+  it('FE-MOB-TRFRM-060: editing a bus with a stored price sends an empty metadata object, not null, so the price survives (#2233)', async () => {
+    const handleSaveTransport = makeSave()
+    const editingTransport = {
+      id: 62, trip_id: 1, type: 'bus', title: 'Airport shuttle', status: 'confirmed', day_id: 12,
+      metadata: { price: '45', priceCurrency: 'EUR' }, endpoints: [],
+    } as unknown as Reservation
+    renderSheet(makePlanner({ editingTransport, handleSaveTransport }))
+    typeTitle('Airport shuttle (late)')
+
+    await submit('common.update')
+    // The server reads null as "clear the column" and only carries the expense
+    // price over into an object, so null here would wipe price / priceCurrency.
+    expect(handleSaveTransport.mock.calls[0][0].metadata).toEqual({})
+  })
 })

server/tests/unit/nest/reservations.service.test.ts

@@ -263,6 +263,23 @@ describe('ReservationsService (DI-native, real SQL)', () => {
       expect(reservation.metadata).toBeNull();
     });
 
+    it('RESV-SVC-043: a bus edit with an empty metadata object keeps the price, the same edit with null drops it (#2233)', async () => {
+      // A bus, car, taxi or ferry has no metadata of its own, so the booking form
+      // rebuilds it as {}. The phone used to send null instead, which this
+      // service rightly reads as "clear the column", and the price went with it.
+      const { trip } = ownerTrip();
+      const res = createReservation(testDb, trip.id, { title: 'Shuttle', type: 'bus' });
+      await updateRows(orm, Reservations, { id: res.id }, { metadata: JSON.stringify({ price: '45', priceCurrency: 'EUR' }) });
+
+      let current = (await svc.getReservation(String(res.id), String(trip.id)))!;
+      let { reservation } = await svc.update(String(res.id), String(trip.id), { metadata: {} }, current);
+      expect(JSON.parse(reservation.metadata as string)).toEqual({ price: '45', priceCurrency: 'EUR' });
+
+      current = (await svc.getReservation(String(res.id), String(trip.id)))!;
+      ({ reservation } = await svc.update(String(res.id), String(trip.id), { metadata: null }, current));
+      expect(reservation.metadata).toBeNull();
+    });
+
     it('RESV-SVC-010: endpoints [] wipes stored endpoints; an absent field leaves them alone', async () => {
       const { trip } = ownerTrip();
       const res = createReservation(testDb, trip.id, { title: 'Bus' });