Merge branch 'feature/nextjs-16-upgrade' - TypeScript and test fixes

Merged changes:
- Reverted Next.js 16 upgrade (Payload CMS 3.68.4 incompatible)
- Fixed all TypeScript errors in test files
- ESLint and typecheck now pass

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

next.config.mjs

@@ -16,7 +16,7 @@ const nextConfig = {
     workerThreads: false,
     cpus: 1,
   },
-  // Your Next.js config here
+  // Webpack configuration for TypeScript/ESM compatibility
   webpack: (webpackConfig) => {
     webpackConfig.resolve.extensionAlias = {
       '.cjs': ['.cts', '.cjs'],

package.json

@@ -73,7 +73,7 @@
     "vitest": "4.0.15"
   },
   "engines": {
-    "node": "^18.20.2 || >=20.9.0",
+    "node": ">=20.9.0",
     "pnpm": "^9 || ^10"
   },
   "pnpm": {

tests/helpers/access-control-test-utils.ts

@@ -26,8 +26,10 @@ export interface MockTenant {
   domains?: Array<{ domain: string }>
 }
 
-export interface MockPayloadRequest extends Partial<PayloadRequest> {
+// Note: Not extending PayloadRequest to allow flexible mock types for testing
+export interface MockPayloadRequest {
   user?: MockUser | null
+  // Allow both Headers and plain object for testing different header formats
   headers: Headers | Record<string, string | string[] | undefined>
   payload: {
     find: ReturnType<typeof vi.fn>
@@ -126,10 +128,10 @@ export function createMockPayloadRequest(
     tenants?: MockTenant[]
   } = {},
 ): MockPayloadRequest {
-  const headers: Record<string, string | string[] | undefined> = {}
+  const headers = new Headers()
 
   if (options.host) {
-    headers['host'] = options.host
+    headers.set('host', options.host)
   }
 
   // Mock payload.find to resolve tenant from host
@@ -306,9 +308,11 @@ export async function executeAccess(
     data?: Record<string, unknown>
   } = {},
 ): Promise<AccessResult> {
+  // Convert string ID to number if needed (Payload access functions expect number | undefined)
+  const numericId = typeof options.id === 'string' ? parseInt(options.id, 10) : options.id
   const result = await accessFn({
     req: request as unknown as PayloadRequest,
-    id: options.id,
+    id: numericId,
     data: options.data,
   })
 

tests/int/email.int.spec.ts

@@ -3,12 +3,13 @@ import type { Payload } from 'payload'
 import type { Tenant } from '@/payload-types'
 
 const mockSendMail = vi.fn(async () => ({ messageId: 'mocked-id' }))
-const mockCreateTransport = vi.fn(() => ({ sendMail: mockSendMail }))
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+const mockCreateTransport = vi.fn((_options?: unknown) => ({ sendMail: mockSendMail }))
 
 vi.mock('nodemailer', () => ({
   __esModule: true,
   default: {
-    createTransport: (...args: unknown[]) => mockCreateTransport(...args),
+    createTransport: (options: unknown) => mockCreateTransport(options),
   },
 }))
 

tests/int/i18n.int.spec.ts

@@ -75,8 +75,13 @@ describe('Payload Localization Integration', () => {
   it('payload config has localization enabled', async () => {
     const payloadConfig = await config
     expect(payloadConfig.localization).toBeDefined()
-    expect(payloadConfig.localization?.locales).toBeDefined()
+    expect(payloadConfig.localization).not.toBe(false)
-    expect(payloadConfig.localization?.defaultLocale).toBe('de')
+    // Type guard for localization config
+    const localization = payloadConfig.localization
+    if (localization && typeof localization === 'object') {
+      expect(localization.locales).toBeDefined()
+      expect(localization.defaultLocale).toBe('de')
+    }
   })
 
   it('payload config has i18n enabled', async () => {

tests/int/search.int.spec.ts

@@ -242,10 +242,12 @@ describe('Search API Integration', () => {
     try {
       const post = await payload.create({
         collection: 'posts',
+        draft: false,
         data: {
           title: 'Searchable Test Post Title',
           slug: `searchable-test-post-${Date.now()}`,
           excerpt: 'This is a searchable excerpt for testing',
+          type: 'blog',
           status: 'published',
           publishedAt: new Date().toISOString(),
           tenant: testTenantId,

tests/unit/access-control/collection-access.unit.spec.ts

@@ -9,7 +9,7 @@
  */
 
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
-import type { Access, PayloadRequest } from 'payload'
+import type { Access, PayloadRequest, Where } from 'payload'
 import {
   createSuperAdmin,
   createTenantUser,
@@ -122,7 +122,7 @@ describe('EmailLogs Collection Access', () => {
       const result = await executeAccess(emailLogsAccess.read, request)
 
       expect(hasFilteredAccess(result)).toBe(true)
-      const tenantIds = getTenantIdsFromInFilter(result as Record<string, unknown>)
+      const tenantIds = getTenantIdsFromInFilter(result as Where)
       expect(tenantIds).toContain(1) // porwoll tenant ID
     })
 
@@ -131,7 +131,7 @@ describe('EmailLogs Collection Access', () => {
       const result = await executeAccess(emailLogsAccess.read, request)
 
       expect(hasFilteredAccess(result)).toBe(true)
-      const tenantIds = getTenantIdsFromInFilter(result as Record<string, unknown>)
+      const tenantIds = getTenantIdsFromInFilter(result as Where)
       expect(tenantIds).toEqual(expect.arrayContaining([1, 4, 5]))
     })
 
@@ -141,7 +141,7 @@ describe('EmailLogs Collection Access', () => {
       const result = await executeAccess(emailLogsAccess.read, request)
 
       expect(hasFilteredAccess(result)).toBe(true)
-      const tenantIds = getTenantIdsFromInFilter(result as Record<string, unknown>)
+      const tenantIds = getTenantIdsFromInFilter(result as Where)
       expect(tenantIds).toContain(1)
       expect(tenantIds).toContain(4)
     })
@@ -159,7 +159,7 @@ describe('EmailLogs Collection Access', () => {
       const result = await executeAccess(emailLogsAccess.read, request)
 
       expect(hasFilteredAccess(result)).toBe(true)
-      const tenantIds = getTenantIdsFromInFilter(result as Record<string, unknown>)
+      const tenantIds = getTenantIdsFromInFilter(result as Where)
       expect(tenantIds).toEqual([])
     })
   })
@@ -377,7 +377,7 @@ describe('Access Control Edge Cases', () => {
       const result = await executeAccess(emailLogsAccess.read, request)
 
       expect(hasFilteredAccess(result)).toBe(true)
-      const tenantIds = getTenantIdsFromInFilter(result as Record<string, unknown>)
+      const tenantIds = getTenantIdsFromInFilter(result as Where)
       expect(tenantIds).toHaveLength(0)
     })
 
@@ -428,7 +428,7 @@ describe('Access Control Edge Cases', () => {
       const result = await executeAccess(emailLogsAccess.read, request)
 
       expect(hasFilteredAccess(result)).toBe(true)
-      const tenantIds = getTenantIdsFromInFilter(result as Record<string, unknown>)
+      const tenantIds = getTenantIdsFromInFilter(result as Where)
       expect(tenantIds.sort()).toEqual([1, 2, 3])
     })
   })

tests/unit/access-control/tenant-access.unit.spec.ts

@@ -6,7 +6,7 @@
  */
 
 import { describe, it, expect, vi, beforeEach } from 'vitest'
-import type { PayloadRequest } from 'payload'
+import type { PayloadRequest, Where } from 'payload'
 import {
   createSuperAdmin,
   createTenantUser,
@@ -173,7 +173,7 @@ describe('tenantScopedPublicRead', () => {
       const result = await executeAccess(tenantScopedPublicRead, request)
 
       expect(hasFilteredAccess(result)).toBe(true)
-      expect(getTenantIdFromFilter(result as Record<string, unknown>)).toBe(1)
+      expect(getTenantIdFromFilter(result as Where)).toBe(1)
     })
 
     it('returns different tenant filter for different domain', async () => {
@@ -181,7 +181,7 @@ describe('tenantScopedPublicRead', () => {
       const result = await executeAccess(tenantScopedPublicRead, request)
 
       expect(hasFilteredAccess(result)).toBe(true)
-      expect(getTenantIdFromFilter(result as Record<string, unknown>)).toBe(4)
+      expect(getTenantIdFromFilter(result as Where)).toBe(4)
     })
 
     it('denies access for unknown domain', async () => {
@@ -286,7 +286,7 @@ describe('Access Control Integration Scenarios', () => {
 
       // Should only see porwoll.de posts
       expect(hasFilteredAccess(result)).toBe(true)
-      expect(getTenantIdFromFilter(result as Record<string, unknown>)).toBe(1)
+      expect(getTenantIdFromFilter(result as Where)).toBe(1)
     })
 
     it('admin editing posts from any tenant', async () => {

tests/unit/security/data-masking.unit.spec.ts

@@ -288,7 +288,7 @@ describe('Data Masking', () => {
     it('handles non-Error objects', () => {
       const notAnError = { message: 'password=secret', code: 500 }
 
-      const masked = maskError(notAnError as Error)
+      const masked = maskError(notAnError as unknown as Error)
 
       expect(masked).toBeDefined()
     })

tests/unit/security/rate-limiter.unit.spec.ts

@@ -205,7 +205,7 @@ describe('Rate Limiter', () => {
         resetIn: 45000,
       }
 
-      const headers = rateLimitHeaders(result, 30)
+      const headers = rateLimitHeaders(result, 30) as Record<string, string>
 
       expect(headers['X-RateLimit-Limit']).toBe('30')
       expect(headers['X-RateLimit-Remaining']).toBe('25')
@@ -220,7 +220,7 @@ describe('Rate Limiter', () => {
         retryAfter: 30,
       }
 
-      const headers = rateLimitHeaders(result, 10)
+      const headers = rateLimitHeaders(result, 10) as Record<string, string>
 
       expect(headers['Retry-After']).toBe('30')
       expect(headers['X-RateLimit-Remaining']).toBe('0')
@@ -233,8 +233,8 @@ describe('Rate Limiter', () => {
         resetIn: 60000,
       }
 
-      const headers = rateLimitHeaders(result, 10)
+      const headers = rateLimitHeaders(result, 10) as Record<string, string>
-      const resetValue = headers['X-RateLimit-Reset'] as string
+      const resetValue = headers['X-RateLimit-Reset']
 
       // The reset value should be a number (either timestamp or seconds)
       expect(resetValue).toBeDefined()

tsconfig.json

@@ -30,15 +30,16 @@
         "./src/payload.config.ts"
       ]
     },
-    "target": "ES2022",
+    "target": "ES2022"
   },
   "include": [
     "next-env.d.ts",
     "**/*.ts",
     "**/*.tsx",
-    ".next/types/**/*.ts"
+    ".next/types/**/*.ts",
+    ".next/dev/types/**/*.ts"
   ],
   "exclude": [
     "node_modules"
-  ],
+  ]
 }