Improve module graph iteration performance

[hardfist]

• Summary
  • swap existing .modules() and .modules().values() iterations for the faster modules_iter/dependencies_iter helpers and batch-update mutations directly via mutable references
  • streamline affected-module calculations by deduplicating incoming dependencies and using precomputed AffectType state for each referencing module
  • tighten async module traversal by collecting unique ESM targets before recursing
• Testing
  • Not run (not requested)

[Copilot]

Pull request overview

This PR optimizes hot-path iteration patterns over the module graph by switching from allocating .modules()/.values()/.keys() maps to using iterator helpers directly, and by reducing repeated work during affected-module and async-module traversal.

Changes:

• Replace several modules().values()/keys() iterations with modules_iter() to avoid intermediate collections.
• Speed up affected-module computation by deduplicating incoming dependencies per referencing module and tracking AffectType incrementally.
• Tighten async module traversal by collecting unique ESM outgoing targets before recursing.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
crates/rspack_core/src/runtime_template.rs	Deduplicates ESM outgoing targets before recursing in async-module traversal.
crates/rspack_core/src/module_graph/mod.rs	Adds iterator/len helpers and switches batch updates to mutate connections/modules in place.
crates/rspack_core/src/incremental/mutations.rs	Streamlines affected-module calculation using per-referencing-module dedup + incremental AffectType aggregation.
crates/rspack_core/src/compilation/module_ids/mod.rs	Uses modules_iter() to avoid allocating a temporary modules map.
crates/rspack_core/src/compilation/build_module_graph/graph_updater/cutout/mod.rs	Uses modules_iter() + then_some for cleaner/faster filtering of rebuild-needed modules.
crates/rspack_core/src/compilation/build_chunk_graph/mod.rs	Uses modules_iter() to gather module identifiers without building an intermediate map.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

module_graph_modules_len() currently computes the size by iterating and counting (iter().count()), which is O(n) and can be surprisingly expensive (especially with overlays). Since the method name implies a cheap length lookup, consider either implementing a real len() on rollback::OverlayMap (e.g., base.len() plus/minus overlay tombstones, O(overlay)) and calling that here, or renaming/documenting this as an O(n) count to avoid misuse in hot paths.

[github-actions]

Rsdoctor Bundle Diff Analysis

Found 5 projects in monorepo, 0 projects with changes.

📊 Quick Summary

Project	Total Size	Change
react-10k	5.7 MB	0
react-1k	825.4 KB	0
rome	984.2 KB	0
react-5k	2.7 MB	0
ui-components	2.2 MB	0

Generated by Rsdoctor GitHub Action

[github-actions]

📦 Binary Size-limit

Comparing 221a375 to chore(deps): update dependency @playwright/test to v1.58.1 (#12874) by renovate[bot]

🎉 Size decreased by 26.00KB from 48.73MB to 48.71MB (⬇️0.05%)

[codspeed-hq]

Merging this PR will not alter performance

✅ 17 untouched benchmarks
⏩ 1 skipped benchmark¹

---

_{Comparing codex/module-graph (221a375) with main (7f1665c)}

Footnotes

1. 1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩