PR #14502: fix: potential error spam during hmr, when using next.js 16 and turbopack

• Repository: payloadcms/payload
• Author: AlessioGr
• State: closed | merged: False
• Link: https://github.com/payloadcms/payload/pull/14502

Description (problem / solution / changelog)

Fixes https://github.com/payloadcms/payload/issues/14419.

In a live-preview enabled page, both the admin panel and the frontend initialize their own getPayload instances, each subscribing to HMR updates. In Next.js 16 with Turbopack, this setup can cause the server console to be flooded with errors like:

Error: Could not find the module "[project]/node_modules/.pnpm/[path-to-importmap-entry]" in the React Client Manifest. This is probably a bug in the React Server Components bundler.

These errors occur when an fs call tries to access the import map during the reload process.

Fix

The import map generation is now deferred using setTimeout and is no longer awaited. This prevents the problematic awaited fs access during HMR reloads.

Video that showcases this issue and the solution on the website template:

https://github.com/user-attachments/assets/afd5e6cf-09ac-4cda-bbdc-88dc4d1e7108

Additional Improvements

Additionally, this PR prevents multiple reload operations from overlapping by skipping new reloads while one is already in progress.

This reduces redundant reload triggers when multiple getPayload instances are subscribed to the same HMR websocket, reducing the chance of something going wrong.

Changed files

• packages/payload/src/index.ts (modified, +28/-11)

PR #14456: feat: next.js 16 support

• Repository: payloadcms/payload
• Author: AlessioGr
• State: closed | merged: True
• Link: https://github.com/payloadcms/payload/pull/14456

Description (problem / solution / changelog)

This PR:

• updates this monorepo to use Next.js 16. Running our test suites against Next.js 16 is required to guarantee support.
• updates all peerDependencies to support the latest Next.js canary.

Individual Next.js 16–related fixes were made in separate, smaller PRs (listed below). As a result, the majority of the changes in this PR are focused on getting the test suite to pass.

Templates will be updated in a separate PR once Next.js 16.2.0 is released.

Current Status / Known Issues

You can use Next.js 16 with Payload, as long as you're using the latest Payload version and Next.js >16.1.1-canary.35 or, if released, 16.2.0.

List of Next.js 16-related PRs that were extracted from this branch

• https://github.com/payloadcms/payload/pull/15270
• https://github.com/payloadcms/payload/pull/14845
• https://github.com/payloadcms/payload/pull/14502
• https://github.com/payloadcms/payload/pull/14558
• https://github.com/payloadcms/payload/pull/14475
• https://github.com/payloadcms/payload/pull/14474
• https://github.com/payloadcms/payload/pull/14473
• https://github.com/payloadcms/payload/pull/14463
• https://github.com/payloadcms/payload/pull/14462

List of Next.js / React issues that were fixed - no longer blockers

• Turbopack HMR stability - vercel/next.js#85883 Currently breaks when a live-preview–enabled page is open (related Payload issue). The Next.js team is actively working on a fix: PR #86239. Fixed in Next.js canary
• Turbopack Build support: PR #86375. Fixed in Next.js canary
• We need to wait for vercel/next.js#84029 to be resolved. We initially expected these hydration errors to be suppressible, but that turned out not to be the case. As a result, this issue is now the final blocker for Next.js 16 support. Most of the CI e2e test failures in this PR are the result of this issue.

Changed files

• docs/performance/overview.mdx (modified, +2/-4)
• next-env.d.ts (modified, +1/-0)
• next.config.mjs (modified, +6/-4)
• package.json (modified, +7/-6)
• packages/admin-bar/package.json (modified, +2/-2)
• packages/db-d1-sqlite/bundle.js (modified, +2/-0)
• packages/db-postgres/bundle.js (modified, +2/-0)
• packages/db-postgres/package.json (modified, +1/-1)
• packages/db-sqlite/bundle.js (modified, +2/-0)
• packages/db-vercel-postgres/package.json (modified, +1/-1)
• packages/live-preview-react/package.json (modified, +2/-2)
• packages/next/bundle.js (modified, +2/-0)
• packages/next/package.json (modified, +5/-5)
• packages/next/src/withPayload/withPayload.js (modified, +36/-0)
• packages/payload/bundle.js (modified, +4/-0)
• packages/payload/package.json (modified, +1/-1)
• packages/payload/src/index.ts (modified, +9/-0)
• packages/plugin-cloud-storage/package.json (modified, +2/-2)
• packages/plugin-ecommerce/package.json (modified, +2/-2)
• packages/plugin-form-builder/package.json (modified, +2/-2)
• packages/plugin-search/package.json (modified, +2/-2)
• packages/plugin-sentry/package.json (modified, +2/-2)
• packages/plugin-seo/package.json (modified, +2/-2)
• packages/plugin-stripe/package.json (modified, +2/-2)
• packages/richtext-lexical/bundle.js (modified, +2/-1)
• packages/richtext-lexical/package.json (modified, +3/-3)
• packages/richtext-lexical/src/exports/server/ast/mdx.ts (modified, +0/-1)
• packages/richtext-lexical/src/packages/@lexical/markdown/MarkdownImport.ts (modified, +0/-1)
• packages/richtext-slate/package.json (modified, +2/-2)
• packages/storage-s3/src/generateSignedURL.ts (modified, +1/-2)
• packages/storage-s3/src/staticHandler.ts (modified, +0/-1)
• packages/translations/package.json (modified, +2/-2)
• packages/ui/bundle.js (modified, +4/-0)
• packages/ui/package.json (modified, +4/-4)
• packages/ui/src/elements/DraggableSortable/index.tsx (modified, +10/-4)
• packages/ui/src/fields/Array/ArrayRow.tsx (modified, +4/-1)
• packages/ui/src/forms/Form/index.tsx (modified, +6/-0)
• packages/ui/src/providers/LivePreview/index.tsx (modified, +9/-2)
• packages/ui/src/providers/Root/index.tsx (modified, +1/-0)
• packages/ui/src/views/Edit/index.tsx (modified, +20/-0)
• pnpm-lock.yaml (modified, +6807/-7931)
• test/access-control/e2e.spec.ts (modified, +8/-9)
• test/access-control/payload-types.ts (modified, +11/-11)
• test/access-control/shared.ts (modified, +1/-1)
• test/admin/e2e/list-view/e2e.spec.ts (modified, +6/-0)
• test/auth/e2e.spec.ts (modified, +1/-0)
• test/bulk-edit/config.ts (modified, +5/-16)
• test/bulk-edit/e2e.spec.ts (modified, +92/-28)
• test/bulk-edit/seed.ts (added, +21/-0)
• test/dev.ts (modified, +0/-1)
• test/docker-compose.yml (modified, +1/-1)
• test/field-error-states/e2e.spec.ts (modified, +3/-7)
• test/fields-relationship/e2e.spec.ts (modified, +0/-1)
• test/fields/collections/Blocks/e2e.spec.ts (modified, +1/-3)
• test/fields/collections/Date/e2e.spec.ts (modified, +10/-6)
• test/fields/collections/Indexed/e2e.spec.ts (modified, +0/-1)
• test/fields/collections/JSON/e2e.spec.ts (modified, +11/-16)
• test/fields/collections/Tabs/e2e.spec.ts (modified, +7/-9)
• test/folders/e2e.spec.ts (modified, +3/-4)
• test/form-state/e2e.spec.ts (modified, +104/-50)
• test/group-by/e2e.spec.ts (modified, +30/-8)
• test/helpers.ts (modified, +41/-0)
• test/helpers/assertToastErrors.ts (modified, +3/-10)
• test/helpers/e2e/copyPasteField.ts (modified, +3/-0)
• test/helpers/e2e/groupBy/addGroupBy.ts (modified, +1/-0)
• test/helpers/e2e/navigateToDoc.ts (modified, +5/-1)
• test/helpers/e2e/sort/moveRow.ts (modified, +3/-0)
• test/helpers/e2e/waitForAutoSaveToRunAndComplete.ts (modified, +3/-0)
• test/helpers/folders/createFolderDoc.ts (modified, +2/-0)
• test/helpers/sdk/types.ts (modified, +1/-0)
• test/i18n/e2e.spec.ts (modified, +2/-0)
• test/lexical/collections/Lexical/e2e/blocks/e2e.spec.ts (modified, +9/-6)
• test/lexical/collections/Lexical/e2e/main/e2e.spec.ts (modified, +6/-0)
• test/localization/config.ts (modified, +0/-12)
• test/localization/e2e.spec.ts (modified, +19/-9)
• test/locked-documents/e2e.spec.ts (modified, +42/-215)
• test/next.config.mjs (modified, +1/-3)
• test/package.json (modified, +6/-6)
• test/plugin-import-export/e2e.spec.ts (modified, +0/-6)
• test/plugin-multi-tenant/config.ts (modified, +6/-1)
• test/plugin-multi-tenant/e2e.spec.ts (modified, +18/-10)
• test/plugin-multi-tenant/seed/index.ts (modified, +2/-23)
• test/uploads/e2e.spec.ts (modified, +0/-3)
• test/versions/e2e.spec.ts (modified, +9/-1)

PR #86239: Turbopack: race condition when rendering two RSC at the same time

• Repository: vercel/next.js
• Author: mischnic
• State: closed | merged: False
• Link: https://github.com/vercel/next.js/pull/86239

Description (problem / solution / changelog)

Related to and closes #85883

Changed files

• test/development/app-dir/hmr-iframe/app/page1/Component.tsx (added, +5/-0)
• test/development/app-dir/hmr-iframe/app/page1/page.tsx (added, +18/-0)
• test/development/app-dir/hmr-iframe/app/page1/subscribeToHMR.ts (added, +55/-0)
• test/development/app-dir/hmr-iframe/app/page2/page.tsx (added, +13/-0)
• test/development/app-dir/hmr-iframe/hmr-iframe.test.ts (added, +35/-0)
• test/development/app-dir/hmr-iframe/next.config.js (added, +5/-0)

PR #86591: Handle cross-page client reference contamination in development

• Repository: vercel/next.js
• Author: unstubbable
• State: closed | merged: True
• Link: https://github.com/vercel/next.js/pull/86591

Description (problem / solution / changelog)

In development, React is tracking I/O for debugging purposes. Under some circumstances it can happen that I/O that is cached in a global variable (generally not recommended!) might be triggered by a component of one page (the owner of that I/O) and also be emitted as I/O debug info for a component of another page that depends on it. If the owner references client components in its props, those couldn't be serialized for the other page because they don't exist in the client reference manifest of that page, leading to the following error:

Error: Could not find the module "<ID>" in the React Client Manifest.
This is probably a bug in the React Server Components bundler.

To support that case, we're now looking for client references in manifests of other pages, but only in development mode.

A better fix might be to pass a joint debugBundlerConfig option to React, alongside the normal bundlerConfig option, or something like that. But for now, this should suffice.

Another option we considered but disregarded is a change in React to ignore missing client references when emitting them as debug info, and emitting an omission placeholder instead. But for the general case this would mask real bugs in the RSC bundler.

As part of this fix, we're removing the clientReferenceManifest and serverActionsManifest properties from the renderOpts. This is unnecessary because they can be consumed directly from the global manifests singleton.

The proxy pattern introduced here follows a similar approach we were already using in createServerModuleMap.

fixes #85883 closes #86239 closes NAR-524

Changed files

• packages/next/errors.json (modified, +5/-1)
• packages/next/src/build/templates/app-page.ts (modified, +2/-8)
• packages/next/src/build/templates/app-route.ts (modified, +2/-6)
• packages/next/src/build/templates/edge-app-route.ts (modified, +2/-6)
• packages/next/src/build/templates/edge-ssr-app.ts (modified, +2/-10)
• packages/next/src/build/webpack/loaders/next-app-loader/index.ts (modified, +8/-1)
• packages/next/src/build/webpack/plugins/flight-manifest-plugin.ts (modified, +1/-1)
• packages/next/src/export/index.ts (modified, +0/-5)
• packages/next/src/server/app-render/action-handler.ts (modified, +6/-19)
• packages/next/src/server/app-render/action-utils.ts (modified, +13/-6)
• packages/next/src/server/app-render/app-render.tsx (modified, +48/-126)
• packages/next/src/server/app-render/create-component-styles-and-scripts.tsx (modified, +0/-1)
• packages/next/src/server/app-render/encryption-utils.ts (modified, +3/-154)
• packages/next/src/server/app-render/encryption.ts (modified, +6/-4)
• packages/next/src/server/app-render/get-css-inlined-link-tags.tsx (modified, +9/-15)
• packages/next/src/server/app-render/get-layer-assets.tsx (modified, +0/-1)
• packages/next/src/server/app-render/manifests-singleton.ts (added, +230/-0)
• packages/next/src/server/app-render/types.ts (modified, +0/-2)
• packages/next/src/server/app-render/use-flight-response.tsx (modified, +8/-11)
• packages/next/src/server/app-render/walk-tree-with-flight-router-state.tsx (modified, +0/-1)
• packages/next/src/server/load-components.ts (modified, +2/-10)
• packages/next/src/server/load-default-error-components.ts (modified, +0/-3)
• packages/next/src/server/use-cache/use-cache-wrapper.ts (modified, +8/-8)
• packages/next/types/$$compiled.internal.d.ts (modified, +3/-3)
• packages/react-refresh-utils/ReactRefreshWebpackPlugin.ts (modified, +7/-0)
• test/development/app-dir/hmr-iframe/app/layout.tsx (added, +5/-0)
• test/development/app-dir/hmr-iframe/app/page1/Component.tsx (added, +5/-0)
• test/development/app-dir/hmr-iframe/app/page1/page.tsx (added, +22/-0)
• test/development/app-dir/hmr-iframe/app/page1/subscribeToHMR.ts (added, +47/-0)
• test/development/app-dir/hmr-iframe/app/page2/page.tsx (added, +13/-0)
• test/development/app-dir/hmr-iframe/hmr-iframe.test.ts (added, +38/-0)