Turbopack: fix split_module correctness for app-router - #95522
Open
jimmyhmiller wants to merge 4 commits into
Open
Turbopack: fix split_module correctness for app-router#95522jimmyhmiller wants to merge 4 commits into
jimmyhmiller wants to merge 4 commits into
Conversation
Contributor
Stats from current PR✅ No significant changes detected📊 All Metrics📖 Metrics GlossaryDev Server Metrics:
Build Metrics:
Change Thresholds:
⚡ Dev Server
📦 Dev Server (Webpack) (Legacy)📦 Dev Server (Webpack)
⚡ Production Builds
📦 Production Builds (Webpack) (Legacy)📦 Production Builds (Webpack)
📦 Bundle SizesBundle Sizes⚡ TurbopackClient Main Bundles
Server Middleware
Build DetailsBuild Manifests
📦 WebpackClient Main Bundles
Polyfills
Pages
Server Edge SSR
Middleware
Build DetailsBuild Manifests
Build Cache
🔄 Shared (bundler-independent)Runtimes
📎 Tarball URLCommit: ab1a79f |
jimmyhmiller
changed the title
Contributor
Failing test suitesCommit: ab1a79f | About building and testing Next.js
Expand output● cache-components-dev-warmup - with runtime prefetch configs › initial load › cached data resolves in the correct phase › cached data + short-stale cached data |
jimmyhmiller
force-pushed
the
jimmym/tree-shaking-skip-internal
branch
from
July 6, 2026 19:00
d30cfc8 to
f57969c
Compare
Contributor
Author
|
Not the most elegant approach. But I found that this internal module was causing these problems. I saw that there were a number of other places we added an exception. So I followed suit. |
jimmyhmiller
marked this pull request as ready for review
July 7, 2026 14:20
lukesandberg
reviewed
Jul 7, 2026
Comment on lines
491
to
492
| .cell()); | ||
| } |
Contributor
There was a problem hiding this comment.
lukesandberg
reviewed
Jul 7, 2026
lukesandberg
reviewed
Jul 7, 2026
lukesandberg
approved these changes
Jul 7, 2026
jimmyhmiller
force-pushed
the
jimmym/tree-shaking-skip-internal
branch
2 times, most recently
from
July 9, 2026 13:54
a824138 to
0440399
Compare
mischnic
reviewed
Jul 9, 2026
Comment on lines
+167
to
+171
| // Tag the ident with a `ModulePart::Exports` part so tree-shaking's | ||
| // `split_module` opt-out (`!ident.parts.is_empty()`) skips this module. | ||
| // Because of the state of this feature, it is unclear if this is competely | ||
| // the right course of action. Not skipping this causes "Duplicate module idents" | ||
| // errors. |
Member
There was a problem hiding this comment.
It would actually be nice to split this up (though the savings are marginaly(
Why do you get duplicate module idents? Shouldn't the module splitting add (internal part X) to all modules?
Member
There was a problem hiding this comment.
This feels like a more fundamental bug in split_module.
You might have your own custom Module via a module rule that doesn't have a ModulePart in the ident either. Then you'd also run into this bug.
- Don't split the generated __nextjs-internal-proxy. client-reference proxy module. Its exports are all used, so splitting yields no benefit and duplicates its <exports> part in the module graph, tripping the duplicate-ident check in ModuleGraph::from_graphs. - Pass the original comments to each fragment so magic-comment annotations (turbopackChunkingType, turbopackExports) are still parsed. Fragment ASTs keep their original spans, so comments resolve at the same byte positions. Without this, references fall back to defaults (ChunkingType::Shared -> Parallel), breaking app-router layout-segment chunk groups. Add e2e coverage for app-router and pages.
Tag the generated __nextjs-internal-proxy module's ident with ModulePart::Exports so it hits split_module's existing !ident.parts.is_empty() opt-out, instead of matching the module name inside split_module. This keeps the decision at the proxy's construction site in next-core rather than hardcoding a Next.js-specific name in the general-purpose turbopack-ecmascript crate. Behavior is unchanged: the proxy is still not split, avoiding the duplicate <exports> part that tripped the duplicate-ident check in ModuleGraph::from_graphs.
The client-reference proxy ident now carries a ModulePart::Exports suffix (e.g. ` <exports>`), so its source-map source no longer ends with the .mjs/.cjs extension. Match the base name with contains() instead of ends_with() so the proxy frame stays ignore-listed and does not leak into runtime error stacks (fixes use-cache-errors redbox snapshot).
jimmyhmiller
force-pushed
the
jimmym/tree-shaking-skip-internal
branch
from
July 27, 2026 19:20
0440399 to
ab1a79f
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Turbopack: fix split_module correctness for app-router
proxy module. Its exports are all used, so splitting yields no benefit
and duplicates its part in the module graph, tripping the
duplicate-ident check in ModuleGraph::from_graphs.
annotations (turbopackChunkingType, turbopackExports) are still
parsed. Fragment ASTs keep their original spans, so comments resolve
at the same byte positions. Without this, references fall back to
defaults (ChunkingType::Shared -> Parallel), breaking app-router
layout-segment chunk groups.