Turbopack server HMR: inline source maps for evaled modules#90561
Open
wbinnssmith wants to merge 1 commit intoserver-hmr-default-implement-clearfrom
Open
Turbopack server HMR: inline source maps for evaled modules#90561wbinnssmith wants to merge 1 commit intoserver-hmr-default-implement-clearfrom
evaled modules#90561wbinnssmith wants to merge 1 commit intoserver-hmr-default-implement-clearfrom
Conversation
nextjs-bot
added
created-by: Turbopack team
Member
Author
|
Warning This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
This stack of pull requests is managed by Graphite. Learn more about stacking. |
This was referenced Feb 26, 2026
Collaborator
Tests Passed |
Collaborator
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: **400 kB** → **400 kB** ✅ -13 B80 files with content-based hashes (individual files not comparable between builds) Server Middleware
Build DetailsBuild Manifests
📦 WebpackClient Main Bundles
Polyfills
Pages
Server Edge SSR
Middleware
Build DetailsBuild Manifests
Build Cache
🔄 Shared (bundler-independent)Runtimes
📝 Changed Files (2 files)Files with changes:
View diffspages-api-tu..time.prod.jsDiff too large to display pages-turbo...time.prod.jsDiff too large to display 📎 Tarball URL |
Merging this PR will not alter performance
Comparing 
Footnotes
|
wbinnssmith
force-pushed
the
server-hmr-sourcemaps
branch
from
8cd12ca to
3c19fa8
Compare
wbinnssmith
changed the title
evaled modules
This adds and calls \`maybeInlineSourcemap()\` to the Turbopack Node.js HMR runtime that appends \`//# sourceURL\` and \`//# sourceMappingURL\` (base64-encoded) to each `eval`ed module entry Test Plan: CI for #90389
wbinnssmith
force-pushed
the
server-hmr-sourcemaps
branch
from
3c19fa8 to
65345c7
Compare
Comment on lines
+26
to
+30
| let code = entry.code + '\n\n//# sourceURL=' + sourceURL | ||
| if (entry.map) { | ||
| code += | ||
| '\n//# sourceMappingURL=data:application/json;charset=utf-8;base64,' + | ||
| Buffer.from(entry.map).toString('base64') |
Contributor
There was a problem hiding this comment.
do we have to inline it? can we use a file reference here? sourceMappingUrl=file://...
this will slow down eval times (and hmr times) since our sourcemaps can contain source content already
Contributor
There was a problem hiding this comment.
oic, entry.map is just the literal contents...
this thread implies you can just append the contents directly: https://issues.chromium.org/issues/41177554
but this is fine
lukesandberg
approved these changes
Feb 26, 2026
Member
|
We need a test case for this |
Member
|
Here's some prior research about HMR sourcemaps: parcel-bundler/parcel#8034 |
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.
Previously, we lost stack frame information when server hmr code was applied through
eval.This adds and calls `maybeInlineSourcemap()` to the Turbopack Node.js HMR runtime that appends `//# sourceURL` and `//# sourceMappingURL` (base64-encoded) to each
evaled module entry.Test Plan: CI for #90389