fix(patches): return empty object for unhandled manifests in loadManifest by nathanschram · Pull Request #1151 · opennextjs/opennextjs-cloudflare

nathanschram · 2026-02-25T07:49:35Z

Summary

Return {} instead of throwing for manifest paths not found during the build-time glob scan in loadManifest() and evalManifest()
Handles Next.js 16.2.0-canary.53+ which introduces new loadManifest() calls for optional/phase-dependent manifests

Problem

Next.js canary adds loadManifest() calls for:

subresource-integrity-manifest.json - only generated when experimental.sri is configured, but loaded unconditionally
Per-route react-loadable-manifest.json - generated by Turbopack, possibly in a different build phase

The adapter's build-time glob scan doesn't find these files, so the patched function throws at runtime, crashing all dynamic routes with 500.

Fix

Replace the throw new Error('Unexpected loadManifest...') fallback with return {}. This follows the same defensive pattern used by other adapter plugins (instrumentation.ts, find-dir.ts) that return safe defaults for missing files.

Test plan

Build a Next.js app with next@canary (16.2.0-canary.53+) using @opennextjs/cloudflare
Verify dynamic/SSR routes no longer return 500
Verify existing manifests still load correctly (app-manifest, build-manifest, etc.)
Verify SRI works correctly when experimental.sri IS configured

Fixes #1141

…Manifest

changeset-bot · 2026-02-25T07:49:40Z

🦋 Changeset detected

Latest commit: a695016

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@opennextjs/cloudflare	Patch

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nathanschram · 2026-03-02T03:32:08Z

Hey @vicb - just wanted to check in on this. No rush at all, I know you're probably busy. Just wanted to make sure the approach looks reasonable to you, or if you'd prefer I take it in a different direction. Happy to adjust anything.

Rovak · 2026-03-19T06:48:06Z

Can confirm that is working for me in production after copying this patch into the project using pnpm patch

bonadio · 2026-03-20T00:24:57Z

Need this fix too.
Thanks

pkg-pr-new · 2026-03-20T06:28:19Z

Open in StackBlitz

npm i https://pkg.pr.new/@opennextjs/cloudflare@1151

commit: a695016

sommeeeer · 2026-03-20T06:34:17Z

LGTM, until this is merged you can use npm i https://pkg.pr.new/@opennextjs/cloudflare@1151.

conico974 · 2026-03-20T07:34:54Z

packages/cloudflare/src/cli/build/patches/plugins/load-manifest.ts

+  // This handles optional manifests (e.g. subresource-integrity-manifest.json when
+  // experimental.sri is not configured) and manifests generated in a different build
+  // phase (e.g. per-route react-loadable-manifest.json with Turbopack).
+  return {};


I don't think this is the right solution, this will just hide other potential errors, if we know the one that could be null, that's the one we should return an empty object, not everything

Good call - updated to handle only the specific manifests that Next.js loads with handleMissing: true (traced through route-module.ts in vercel/next.js).

The five optional manifests for loadManifest:

react-loadable-manifest.json - Turbopack per-route, not all routes have dynamic imports

subresource-integrity-manifest.json - only when experimental.sri configured

server-reference-manifest.json - App Router only, Pages Router never generates

dynamic-css-manifest.json - Pages Router + Webpack only

fallback-build-manifest.json - only for /_error page

Everything else still throws. Same approach for evalManifest - only _client-reference-manifest.js gets a safe default ({ __RSC_MANIFEST: {} }) since it's optional for static metadata routes.

conico974 · 2026-03-20T07:35:00Z

packages/cloudflare/src/cli/build/patches/plugins/load-manifest.ts

  $PATH = $PATH.replaceAll(${JSON.stringify(sep)}, ${JSON.stringify(posix.sep)});
  ${returnManifests}
-  throw new Error(\`Unexpected evalManifest(\${$PATH}) call!\`);
+  return {};


Addressed - evalManifest now only handles _client-reference-manifest.js (optional for static metadata routes per route-module.ts line 343). Returns { __RSC_MANIFEST: {} } as the safe default structure. Everything else still throws.

@conico974

Address review feedback from @conico974 — instead of returning {} for all unknown manifests (which would hide genuine errors), only handle the specific manifests that Next.js loads with handleMissing: true. loadManifest optional manifests (from vercel/next.js route-module.ts): - react-loadable-manifest.json (Turbopack per-route) - subresource-integrity-manifest.json (experimental.sri) - server-reference-manifest.json (App Router only) - dynamic-css-manifest.json (Pages Router + Webpack only) - fallback-build-manifest.json (/_error page only) evalManifest optional manifests: - _client-reference-manifest.js (static metadata routes) Everything else still throws to surface genuine errors.

bonadio · 2026-03-20T17:32:55Z

LGTM, until this is merged you can use npm i https://pkg.pr.new/@opennextjs/cloudflare@1151.

This did not work for me, trying to run next 16.2 still receives "Unexpected loadManifest(/.next/server/prefetch-hints.json) call!" running with wrangler dev locally

matthewvolk · 2026-03-20T19:39:51Z

Hey @nathanschram — we've been testing Next.js 16.2.0 (stable, not canary) on Cloudflare Workers and can confirm this PR is needed alongside #1160 for things to work.

We found one issue during testing (after manually applying the patch from this PR locally): some manifests are requested without the .json extension, so the $PATH.endsWith("...-manifest.json") checks don't match them.

Root cause

Next.js defines some manifest constants without .json:

SUBRESOURCE_INTEGRITY_MANIFEST = "subresource-integrity-manifest" (source)
DYNAMIC_CSS_MANIFEST = "dynamic-css-manifest" (same file)

When loadManifest() is called with these constants, the path ends up as e.g. /.next/server/dynamic-css-manifest — no .json extension.

My suggestion for this PR

For each manifest in the fallback list, check both with and without .json:

$PATH.endsWith("dynamic-css-manifest.json") || $PATH.endsWith("dynamic-css-manifest")

Or strip .json from the path before matching:

const normalizedPath = $PATH.replace(/\.json$/, "");
if (normalizedPath.endsWith("dynamic-css-manifest")) return {};

After manually applying (locally) #1160 + this PR + the extensionless fix above, I can confirm that our Next.js 16.2.0 app renders successfully on Cloudflare Workers (for Platforms, in our case):

next-16-2-0-running-after-manual-patches

Happy to help with the fix or open a follow-up PR if that's easier. Thanks for this PR!

conico974

LGTM Thanks for the fix

conico974 · 2026-03-21T08:13:48Z

@nathanschram Could You fix the prettier issue please ?

- Fix prettier formatting in changeset - Strip .json extension before matching optional manifests since Next.js defines some constants without it (SUBRESOURCE_INTEGRITY_MANIFEST, DYNAMIC_CSS_MANIFEST, SERVER_REFERENCE_MANIFEST) - Add prefetch-hints to the optional manifest list (new in Next.js 16.2) - All 236 tests pass, tsc clean, prettier clean Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

nathanschram · 2026-03-21T08:40:25Z

@conico974 Prettier issue should be fixed now - sorry about that.

@matthewvolk Great catch on the extensionless manifests - I've updated the matching to strip .json before comparison, so it now handles both dynamic-css-manifest and dynamic-css-manifest.json. Verified against the Next.js constants in shared/lib/constants.ts where SUBRESOURCE_INTEGRITY_MANIFEST, DYNAMIC_CSS_MANIFEST, and SERVER_REFERENCE_MANIFEST are all defined without the extension.

@bonadio Added prefetch-hints to the optional manifest list as well - it's a new constant (PREFETCH_HINTS = 'prefetch-hints.json') in Next.js 16.2.

Summary of changes in the latest push:

Prettier fix on changeset
Extensionless manifest matching (strips .json before checking)
prefetch-hints added to the optional list
All 236 tests pass, tsc clean

nathanschram added 2 commits February 25, 2026 07:31

fix: return empty object for unhandled manifests in loadManifest/eval…

0d3bc85

…Manifest

chore: add changeset for load-manifest fix

5c0f1be

nathanschram mentioned this pull request Feb 25, 2026

[BUG] Unexpected loadManifest calls for new manifest files introduced in Next.js 16.2.0-canary #1141

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sommeeeer approved these changes Mar 20, 2026

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conico974 requested changes Mar 20, 2026

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matthewvolk mentioned this pull request Mar 20, 2026

fix(patches): include prefetch-hints.json in loadManifest glob for Next.js 16.2 #1160

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conico974 approved these changes Mar 21, 2026

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conico974 merged commit a143282 into opennextjs:main Mar 21, 2026
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workers-frameworks mentioned this pull request Mar 21, 2026

Version Packages #1161

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conico974 added a commit to opennextjs/adapters-api that referenced this pull request Mar 21, 2026

port pr opennextjs/opennextjs-cloudflare#1151

92e3d80

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nathanschram commented Feb 25, 2026

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