refactor(trips): leaving a trip reaches the journal link through a port, not an import

TripMembersService called TripJournalLinkService directly, which made trip-members and journey depend on each other (lint:boundaries). The roster now declares TRIP_MEMBER_DEPARTURE and calls memberLeft in the transaction that removes the member; the journey domain binds it globally (TripMemberDepartureModule), the way JourneyAccessModule binds the gateway's JOURNEY_ACCESS. Suites that build TripMembersModule alone import MemberDepartureStubModule.

server/src/nest/app.module.ts

@@ -53,6 +53,7 @@ import { DawarichModule } from './integrations/dawarich.module';
 import { JourneyAccessModule } from './journey/journey-access.module';
 import { JourneyModule } from './journey/journey.module';
 import { TripJournalLinkModule } from './journey/trip-journal-link.module';
+import { TripMemberDepartureModule } from './journey/trip-member-departure.module';
 import { LlmParseModule } from './llm-parse/llm-parse.module';
 import { ManagedExtModule } from './managed/managed-ext.module';
 import { MapsModule } from './maps/maps.module';
@@ -168,6 +169,7 @@ import { APP_FILTER, APP_GUARD, APP_INTERCEPTOR, APP_PIPE } from '@nestjs/core';
     DawarichModule,
     JourneyModule,
     TripJournalLinkModule,
+    TripMemberDepartureModule,
     CollectionsModule,
     ShareModule,
     TripInviteModule,

server/src/nest/journey/trip-journal-link.module.ts

@@ -14,11 +14,10 @@ import { Module } from '@nestjs/common';
 
 /**
  * A trip showing one journal from the Journey addon: the link, its routes and
- * its MCP tools. Its own module rather than part of JourneyModule, because the
- * trip roster needs `TripJournalLinkService.dropMember` when someone leaves,
- * and TripMembersModule must not pull in the whole journey surface (uploads,
- * memories, both photo providers) for that. It imports nothing from the trip
- * roster in return, so the edge runs one way.
+ * its MCP tools. Its own module rather than part of JourneyModule, so the
+ * binding of the trip roster's departure port (TripMemberDepartureModule) does
+ * not pull in the whole journey surface (uploads, memories, both photo
+ * providers).
  */
 @Module({
   imports: [

server/src/nest/journey/trip-journal-link.service.ts

@@ -7,6 +7,7 @@ import { forbidden, notFound } from '../common/domain-error';
 import { UnitOfWork } from '../database/unit-of-work';
 import { PermissionsService } from '../permissions/permissions.service';
 import { RealtimeService } from '../realtime/realtime.service';
+import type { TripMemberDeparture } from '../trip-members/trip-member-departure.types';
 import { TripAccessService } from '../trip-membership/trip-access.service';
 import { JourneyDomainService } from './journey-domain.service';
 import { InjectRepository } from '@mikro-orm/nestjs';
@@ -41,7 +42,7 @@ const NOT_LINKED = 'No journal is linked to this trip';
  * alone or the journal's owner alone is enough.
  */
 @Injectable()
-export class TripJournalLinkService {
+export class TripJournalLinkService implements TripMemberDeparture {
   constructor(
     @InjectRepository(TripJournalLinks) private readonly links: TripJournalLinksRepository,
     @InjectRepository(JourneyContributors) private readonly contributors: JourneyContributorsRepository,
@@ -212,7 +213,7 @@ export class TripJournalLinkService {
    * later does not quietly reopen the journal. Their access already ended with
    * the membership; this only tidies the row. Runs in the caller's transaction.
    */
-  async dropMember(tripId: number, userId: number): Promise<void> {
+  async memberLeft(tripId: number, userId: number): Promise<void> {
     await this.links.deleteMember(tripId, userId);
   }
 }

server/src/nest/journey/trip-member-departure.module.ts

@@ -0,0 +1,18 @@
+import { TRIP_MEMBER_DEPARTURE } from '../trip-members/trip-member-departure.types';
+import { TripJournalLinkModule } from './trip-journal-link.module';
+import { TripJournalLinkService } from './trip-journal-link.service';
+import { Global, Module } from '@nestjs/common';
+
+/**
+ * Binds the trip roster's TRIP_MEMBER_DEPARTURE port to TripJournalLinkService,
+ * so someone leaving a trip also leaves its journal link. Global so
+ * TripMembersModule resolves it without importing the journey domain;
+ * AppModule imports it next to the roster.
+ */
+@Global()
+@Module({
+  imports: [TripJournalLinkModule],
+  providers: [{ provide: TRIP_MEMBER_DEPARTURE, useExisting: TripJournalLinkService }],
+  exports: [TRIP_MEMBER_DEPARTURE],
+})
+export class TripMemberDepartureModule {}

server/src/nest/trip-members/trip-member-departure.types.ts

@@ -0,0 +1,15 @@
+/**
+ * What the trip roster tells the rest of the app when someone leaves a trip.
+ *
+ * A port rather than the journal link service itself: the journey domain
+ * already depends on the trip roster through others, so reaching into it from
+ * here closed a cycle. The journey domain binds the token
+ * (TripMemberDepartureModule), and the roster calls it inside the transaction
+ * that removes the member.
+ */
+export const TRIP_MEMBER_DEPARTURE = Symbol('TRIP_MEMBER_DEPARTURE');
+
+export interface TripMemberDeparture {
+  /** `userId` is off the trip now; whatever they held through it goes too. Runs in the caller's transaction. */
+  memberLeft(tripId: number, userId: number): Promise<void>;
+}

server/src/nest/trip-members/trip-members.module.ts

@@ -4,7 +4,6 @@ import { Users } from '../../db/entities/Users.entity';
 import { AuditModule } from '../audit/audit.module';
 import { AuthModule } from '../auth/auth.module';
 import { BudgetModule } from '../budget/budget.module';
-import { TripJournalLinkModule } from '../journey/trip-journal-link.module';
 import { NotificationsModule } from '../notifications/notifications.module';
 import { PermissionsModule } from '../permissions/permissions.module';
 import { RealtimeModule } from '../realtime/realtime.module';
@@ -26,6 +25,9 @@ import { Module } from '@nestjs/common';
  * `DatabaseModule` is gone (Plan 4 Task 4) — `TripMembersService` is fully
  * repository-backed (`getTripForViewer` → `TripsRepository.findForViewer`,
  * `canAccessTrip` → `TripsRepository.findAccessible`).
+ *
+ * Leaving a trip also leaves its journal link, through the TRIP_MEMBER_DEPARTURE
+ * port the journey domain binds globally (TripMemberDepartureModule).
  */
 @Module({
   imports: [
@@ -35,7 +37,6 @@ import { Module } from '@nestjs/common';
     AuditModule,
     AuthModule,
     BudgetModule,
-    TripJournalLinkModule,
     MikroOrmModule.forFeature([Trips, TripMembers, Users]),
   ],
   controllers: [TripMembersController],

server/src/nest/trip-members/trip-members.service.ts

@@ -11,12 +11,12 @@ import { BudgetService } from '../budget/budget.service';
 import { avatarUrl } from '../common/avatarUrl';
 import { NotFoundError, ValidationError } from '../common/domain-errors';
 import { UnitOfWork } from '../database/unit-of-work';
-import { TripJournalLinkService } from '../journey/trip-journal-link.service';
 import { NotificationsService } from '../notifications/notifications.service';
 import { PermissionsService } from '../permissions/permissions.service';
 import { RealtimeService } from '../realtime/realtime.service';
+import { TRIP_MEMBER_DEPARTURE, type TripMemberDeparture } from './trip-member-departure.types';
 import { InjectRepository } from '@mikro-orm/nestjs';
-import { Injectable } from '@nestjs/common';
+import { Inject, Injectable } from '@nestjs/common';
 import type { TrekWsPayload, TrekWsTripEventName } from '@trek/shared';
 
 import { randomUUID } from 'crypto';
@@ -80,7 +80,7 @@ export class TripMembersService {
     private readonly permissions: PermissionsService,
     private readonly realtime: RealtimeService,
     private readonly notifications: NotificationsService,
-    private readonly journalLinks: TripJournalLinkService,
+    @Inject(TRIP_MEMBER_DEPARTURE) private readonly departure: TripMemberDeparture,
     private readonly uow: UnitOfWork,
     @InjectRepository(Trips) private readonly tripsRepo: TripsRepository,
     @InjectRepository(TripMembers) private readonly tripMembersRepo: TripMembersRepository,
@@ -203,7 +203,7 @@ export class TripMembersService {
     // must not quietly reopen it.
     await this.uow.transactional(async () => {
       await this.tripMembersRepo.remove(tripId, targetUserId);
-      await this.journalLinks.dropMember(tripId, targetUserId);
+      await this.departure.memberLeft(tripId, targetUserId);
     });
   }
 

server/tests/helpers/journey-share-repos.ts

@@ -2,8 +2,12 @@ import { JourneyBooks } from '../../src/db/entities/JourneyBooks.entity';
 import { JourneyShareTokens } from '../../src/db/entities/JourneyShareTokens.entity';
 import type { JourneyBooksRepository } from '../../src/db/repositories/JourneyBooks.repository';
 import type { JourneyShareTokensRepository } from '../../src/db/repositories/JourneyShareTokens.repository';
-import type { TripJournalLinkService } from '../../src/nest/journey/trip-journal-link.service';
+import {
+  TRIP_MEMBER_DEPARTURE,
+  type TripMemberDeparture,
+} from '../../src/nest/trip-members/trip-member-departure.types';
 import { sharedTestOrm } from './test-uow';
+import { Global, Module } from '@nestjs/common';
 
 import type Database from 'better-sqlite3';
 
@@ -28,13 +32,19 @@ export function createTestJourneyBooksRepo(db: Database.Database): Promise<Journ
 }
 
 /**
- * TripJournalLinkService for the suites that hand-build TripMembersService:
- * leaving a trip only has to drop the member from a linked journal, and what
- * that does to the journal's access is pinned by the TJL integration tests
- * against the real service.
+ * The trip roster's departure port for the suites that build TripMembersService
+ * without the journey domain: leaving a trip only has to tell the port, and what
+ * that does to a linked journal is pinned by the TJL integration tests against
+ * the real binding.
  */
-export function journalLinksStub(
-  dropMember: TripJournalLinkService['dropMember'] = async () => {},
-): TripJournalLinkService {
-  return { dropMember } as unknown as TripJournalLinkService;
+export function journalLinksStub(memberLeft: TripMemberDeparture['memberLeft'] = async () => {}): TripMemberDeparture {
+  return { memberLeft };
 }
+
+/** The same stub bound globally, for a `createTestModule` that imports TripMembersModule. */
+@Global()
+@Module({
+  providers: [{ provide: TRIP_MEMBER_DEPARTURE, useValue: journalLinksStub() }],
+  exports: [TRIP_MEMBER_DEPARTURE],
+})
+export class MemberDepartureStubModule {}

server/tests/unit/nest/budget.former-members.test.ts

@@ -14,6 +14,7 @@ import { createSnapshotTestDb } from '../../helpers/db-mock';
 import { findRow } from '../../helpers/factories/rows';
 import { addTripMember, makeTrip } from '../../helpers/factories/trips';
 import { makeUser } from '../../helpers/factories/users';
+import { MemberDepartureStubModule } from '../../helpers/journey-share-repos';
 import { createTestModule, type TestModule } from '../../helpers/test-module';
 import { MikroORM } from '@mikro-orm/core';
 
@@ -26,7 +27,7 @@ let membersSvc: TripMembersService;
 const orm = () => t.get(MikroORM);
 
 beforeAll(async () => {
-  t = await createTestModule({ db, imports: [TripMembersModule] });
+  t = await createTestModule({ db, imports: [TripMembersModule, MemberDepartureStubModule] });
   budget = t.get(BudgetService);
   membersSvc = t.get(TripMembersService);
 });

server/tests/unit/nest/trip-members.guest-departure.test.ts

@@ -19,6 +19,7 @@ import { createSnapshotTestDb } from '../../helpers/db-mock';
 import { countRows, findRow, findRows, updateRows } from '../../helpers/factories/rows';
 import { addTripMember, makeTrip } from '../../helpers/factories/trips';
 import { makeUser } from '../../helpers/factories/users';
+import { MemberDepartureStubModule } from '../../helpers/journey-share-repos';
 import { createTestModule, type TestModule } from '../../helpers/test-module';
 import { MikroORM } from '@mikro-orm/core';
 
@@ -31,7 +32,7 @@ let budget: BudgetService;
 const orm = () => t.get(MikroORM);
 
 beforeAll(async () => {
-  t = await createTestModule({ db, imports: [TripMembersModule] });
+  t = await createTestModule({ db, imports: [TripMembersModule, MemberDepartureStubModule] });
   members = t.get(TripMembersService);
   budget = t.get(BudgetService);
 });