fix(api): use PrismaClientKnownRequestError instanceof, add ConflictException for duplicate routes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/api/src/modules/routes/routes.controller.ts

@@ -11,8 +11,8 @@ export class RoutesController {
   }
 
   @Post()
-  create(@Body() body: { sourceGroupId?: string; targetGroupId?: string }) {
-    return this.routesService.create(body.sourceGroupId ?? '', body.targetGroupId ?? '');
+  create(@Body() body: { sourceGroupId: string; targetGroupId: string }) {
+    return this.routesService.create(body.sourceGroupId, body.targetGroupId);
   }
 
   @Delete(':id')

apps/api/src/modules/routes/routes.service.spec.ts

@@ -1,5 +1,6 @@
 import { Test, TestingModule } from '@nestjs/testing';
-import { BadRequestException, NotFoundException } from '@nestjs/common';
+import { BadRequestException, ConflictException, NotFoundException } from '@nestjs/common';
+import { Prisma } from '@prisma/client';
 import { RoutesService } from './routes.service';
 import { PrismaService } from '../../prisma/prisma.service';
 
@@ -77,6 +78,15 @@ describe('RoutesService', () => {
     it('throws BadRequestException when targetGroupId is empty', async () => {
       await expect(service.create('grp_1', '')).rejects.toThrow(BadRequestException);
     });
+
+    it('throws ConflictException when route already exists (Prisma P2002)', async () => {
+      const p2002 = new Prisma.PrismaClientKnownRequestError('Unique constraint', {
+        code: 'P2002',
+        clientVersion: '6.0.0',
+      });
+      mockPrisma.syncRoute.create.mockRejectedValueOnce(p2002);
+      await expect(service.create('grp_1', 'grp_2')).rejects.toThrow(ConflictException);
+    });
   });
 
   describe('remove', () => {
@@ -86,7 +96,11 @@ describe('RoutesService', () => {
     });
 
     it('throws NotFoundException when route does not exist (Prisma P2025)', async () => {
-      mockPrisma.syncRoute.delete.mockRejectedValueOnce({ code: 'P2025' });
+      const p2025 = new Prisma.PrismaClientKnownRequestError('Record not found', {
+        code: 'P2025',
+        clientVersion: '6.0.0',
+      });
+      mockPrisma.syncRoute.delete.mockRejectedValueOnce(p2025);
       await expect(service.remove('bad_id')).rejects.toThrow(NotFoundException);
     });
   });

apps/api/src/modules/routes/routes.service.ts

@@ -1,4 +1,5 @@
-import { BadRequestException, Injectable, NotFoundException } from '@nestjs/common';
+import { BadRequestException, ConflictException, Injectable, NotFoundException } from '@nestjs/common';
+import { Prisma } from '@prisma/client';
 import { PrismaService } from '../../prisma/prisma.service';
 
 const routeInclude = {
@@ -22,17 +23,24 @@ export class RoutesService {
     if (!sourceGroupId || !targetGroupId) {
       throw new BadRequestException('sourceGroupId and targetGroupId are required');
     }
-    return this.prisma.syncRoute.create({
-      data: { sourceGroupId, targetGroupId },
-      include: routeInclude,
-    });
+    try {
+      return await this.prisma.syncRoute.create({
+        data: { sourceGroupId, targetGroupId },
+        include: routeInclude,
+      });
+    } catch (e) {
+      if (e instanceof Prisma.PrismaClientKnownRequestError && e.code === 'P2002') {
+        throw new ConflictException('A route between these groups already exists');
+      }
+      throw e;
+    }
   }
 
   async remove(id: string) {
     try {
       await this.prisma.syncRoute.delete({ where: { id } });
     } catch (e) {
-      if ((e as { code?: string })?.code === 'P2025') {
+      if (e instanceof Prisma.PrismaClientKnownRequestError && e.code === 'P2025') {
         throw new NotFoundException(`Route ${id} not found`);
       }
       throw e;