### What?
Adds a `modules` field to two tracing spans that cover module graph
construction:
- `"module graph for endpoint"` span (per-page graph, in `app.rs`) —
records the total number of modules across all `SingleModuleGraph`s
built for that endpoint.
- `"whole app module graph"` span (new info-level span wrapping
`whole_app_module_graph_operation` in `project.rs`) — records the
combined module count of the base graph and the additional-entries
graph.
Also adds a `module_count()` method to `SingleModuleGraph` (as a
`#[turbo_tasks::function]` returning `Vc<u64>`) that exposes
`number_of_modules`.
### Why?
Module graph size directly affects build and HMR performance. Without a
count in the trace, it is impossible to correlate span duration with
graph size or spot regressions where the graph grows unexpectedly.
Surfacing the count as a structured span field makes it queryable
without requiring log parsing.
### How?
- `SingleModuleGraph::module_count()` is a cheap
`#[turbo_tasks::function]` that wraps the already-computed
`number_of_modules: usize` field as a `Vc<u64>`.
- Both call sites follow the deferred-field pattern already used in
`ProjectContainer::initialize`: the span is created with `modules =
Empty` before the `async move` block, `span.record("modules", count)` is
called once the graphs are ready, and `span_clone` is passed to
`.instrument()` so the field is recorded on the correct span.
- Module counts are summed across all graphs that contribute to the
endpoint/app.
---------
Co-authored-by: Tobias Koppers <[email protected]>
Co-authored-by: Claude <[email protected]>
Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com>
Next.js
Getting Started
Used by some of the world's largest companies, Next.js enables you to create full-stack web applications by extending the latest React features, and integrating powerful Rust-based JavaScript tooling for the fastest builds.
- Visit our Learn Next.js course to get started with Next.js.
- Visit the Next.js Showcase to see more sites built with Next.js.
Documentation
Visit https://nextjs.org/docs to view the full documentation.
Community
The Next.js community can be found on GitHub Discussions where you can ask questions, voice ideas, and share your projects with other people.
To chat with other community members you can join the Next.js Discord server.
Do note that our Code of Conduct applies to all Next.js community channels. Users are highly encouraged to read and adhere to it to avoid repercussions.
Contributing
Contributions to Next.js are welcome and highly appreciated. However, before you jump right into it, we would like you to review our Contribution Guidelines to make sure you have a smooth experience contributing to Next.js.
Good First Issues:
We have a list of good first issues that contain bugs that have a relatively limited scope. This is a great place for newcomers and beginners alike to get started, gain experience, and get familiar with our contribution process.
Security
If you believe you have found a security vulnerability in Next.js, we encourage you to responsibly disclose this and NOT open a public issue.
To participate in our Open Source Software Bug Bounty program, please email [email protected]. We will add you to the program and provide further instructions for submitting your report.