feat(watch): use new watcher to support watch mode by hyf0 · Pull Request #8475 · rolldown/rolldown

hyf0 · 2026-02-26T13:32:05Z

Summary

Wire up rolldown_watcher to fully replace the legacy watcher (crates/rolldown/src/watch/).

Deprecate watch.notify option and add watch.watcher with usePolling / pollInterval (flat options instead of nested notify struct)
Replace setInterval keep-alive hack with pending waitForClose() Promise
Move event dispatching from channel-based (rx.recv() loop) to trait-based (WatcherEventHandler)
Use with_cached_bundle_experimental for split-phase builds — register FS watches between scan and write so render-hook file changes are detected (see meta/design/watch-mode.md "Split-Phase Build")
Add kind consolidation during debounce (Create+Update→Create, Create+Delete→removed, Delete+Create→Update) — see meta/design/watch-mode.md "Kind Consolidation"
Simplify WatcherEmitter to a thin emit() dispatcher, move event decoding to Watcher.createEventCallback()
Add BindingWatcherState (Pending→Running→Closed) in NAPI binding layer

I will fix reviews in separate PRs, this PR is too cumbersome to make changes

Test plan

cargo test -p rolldown_watcher — 17 unit tests pass
pnpm --filter rolldown-tests test:watcher — 25 integration tests pass
just roll

🤖 Generated with Claude Code

hyf0 · 2026-02-26T13:32:23Z

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hyf0 · 2026-03-01T13:22:31Z

Finally all tests passed.

crates/rolldown_binding/src/watcher.rs

Copilot

Pull request overview

This PR migrates Rolldown’s watch mode to the new rolldown_watcher implementation, updating the JS/TS API surface, NAPI bindings, and internal Rust watch/build flow to support the new watcher model and keepalive mechanism.

Changes:

Introduces watch.watcher (usePolling / pollInterval) and deprecates watch.notify, updating option validation, bindingification, and tests.
Replaces the old JS keepalive setInterval hack with a native waitForClose() promise in the binding/watcher stack.
Refactors event bridging from Rust → NAPI → JS to a trait/callback based flow and updates watch build orchestration (split-phase build hooks).

Reviewed changes

Copilot reviewed 29 out of 30 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
packages/rolldown/tests/watch/watch.test.ts	Updates watch tests to use polling for CI stability and mtime-safe edits.
packages/rolldown/tests/validate-option.test.ts	Updates expected validation warning strings and deprecation messaging.
packages/rolldown/src/utils/validator.ts	Adds schema for watcher polling options and updates deprecated option messaging.
packages/rolldown/src/utils/bindingify-input-options.ts	Deprecates `watch.notify`, merges into `watch.watcher`, and forwards polling options to bindings.
packages/rolldown/src/options/input-options.ts	Introduces `WatcherFileWatcherOptions`, adds `watch.watcher`, and marks `watch.notify` deprecated.
packages/rolldown/src/index.ts	Re-exports `WatcherFileWatcherOptions`.
packages/rolldown/src/binding.d.cts	Updates BindingWatcher API (constructor + `waitForClose`) and watch option fields.
packages/rolldown/src/api/watch/watcher.ts	Switches to new binding watcher API and moves event decoding into a callback mapper.
packages/rolldown/src/api/watch/watch-emitter.ts	Removes interval keepalive and simplifies emitter into an async dispatcher.
meta/design/watch-mode.md	Updates design doc for split-phase build, NAPI bridge, and watcher lifecycle.
crates/rolldown_watcher/src/watcher.rs	Adds polling configuration, default debounce changes, and close notification for NAPI keepalive.
crates/rolldown_watcher/src/watch_task.rs	Implements split-phase build using `with_cached_bundle_experimental` and improves watch-file registration timing.
crates/rolldown_watcher/src/watch_coordinator.rs	Improves fatal error formatting via diagnostics.
crates/rolldown_watcher/src/state.rs	Adds a new (currently unreferenced) watcher state machine file.
crates/rolldown_watcher/src/msg.rs	Adds a new (currently unreferenced) message enum file.
crates/rolldown_watcher/src/event.rs	Preserves raw diagnostics in watch error events for richer binding conversion.
crates/rolldown_testing/_config.schema.json	Extends schema to include polling options in watch config.
crates/rolldown_common/src/lib.rs	Removes `NotifyOption` from public re-exports.
crates/rolldown_common/src/inner_bundler_options/types/watch_option.rs	Replaces notify options with `use_polling` / `poll_interval` on watch options.
crates/rolldown_binding/src/watcher.rs	Replaces legacy channel-driven watcher with `rolldown_watcher` + `wait_for_close` support and state machine.
crates/rolldown_binding/src/types/binding_watcher_event.rs	Reworks BindingWatcherEvent representation and accessors for the new event model.
crates/rolldown_binding/src/options/binding_input_options/binding_watch_option.rs	Forwards polling options from JS bindings into Rust watch options.
crates/rolldown_binding/Cargo.toml	Adds dependency on `rolldown_watcher`.
crates/rolldown/src/watcher.rs	Updates watcher constructors to remove notify option dependency.
crates/rolldown/src/watch/watcher.rs	Removes legacy notify config wiring for the old watcher.
crates/rolldown/src/bundler/bundler.rs	Makes `reset_closed_for_watch_mode` public for watcher-driven rebuilds.
crates/rolldown/src/bundle/bundle.rs	Exposes scan/generate APIs for split-phase orchestration.
crates/rolldown/examples/watch.rs	Updates example to new watcher constructor signature.
Cargo.toml	Adds `rolldown_watcher` to workspace dependencies.
Cargo.lock	Updates lockfile for new dependency graph.

packages/rolldown/src/api/watch/watcher.ts

crates/rolldown_watcher/src/state.rs

packages/rolldown/tests/watch/watch.test.ts

crates/rolldown_binding/src/watcher.rs

crates/rolldown_watcher/src/msg.rs

packages/rolldown/tests/watch/watch.test.ts

meta/design/watch-mode.md

github-actions · 2026-03-01T13:41:20Z

Benchmarks Rust

target: main(6e2d82f)
pr: 02-26-feat_watch_use_new_watcher_to_support_watch_mode(be8bd7c)

group                                                        pr                                     target
-----                                                        --                                     ------
bundle/bundle@multi-duplicated-top-level-symbol              1.00     79.3±1.91ms        ? ?/sec    1.01     79.8±2.01ms        ? ?/sec
bundle/bundle@multi-duplicated-top-level-symbol-sourcemap    1.00     88.0±1.78ms        ? ?/sec    1.01     89.1±3.15ms        ? ?/sec
bundle/bundle@rome_ts                                        1.00    160.9±4.61ms        ? ?/sec    1.00    160.8±3.92ms        ? ?/sec
bundle/bundle@rome_ts-sourcemap                              1.00    177.8±3.23ms        ? ?/sec    1.00    178.1±3.64ms        ? ?/sec
bundle/bundle@threejs                                        1.00     72.1±3.28ms        ? ?/sec    1.01     72.7±2.77ms        ? ?/sec
bundle/bundle@threejs-sourcemap                              1.00     79.2±2.11ms        ? ?/sec    1.01     79.9±1.30ms        ? ?/sec
bundle/bundle@threejs10x                                     1.00    769.7±7.91ms        ? ?/sec    1.00    772.5±6.87ms        ? ?/sec
bundle/bundle@threejs10x-sourcemap                           1.00    881.9±7.62ms        ? ?/sec    1.00    878.4±6.46ms        ? ?/sec
scan/scan@rome_ts                                            1.00     78.7±2.29ms        ? ?/sec    1.01     79.4±1.79ms        ? ?/sec
scan/scan@threejs                                            1.01     27.9±1.60ms        ? ?/sec    1.00     27.5±0.42ms        ? ?/sec
scan/scan@threejs10x                                         1.00    271.2±2.74ms        ? ?/sec    1.01    274.2±4.15ms        ? ?/sec

crates/rolldown_binding/src/watcher.rs

netlify · 2026-03-01T16:41:20Z

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crates/rolldown/src/watch/watcher.rs

packages/rolldown/src/options/input-options.ts

hyf0 · 2026-03-02T06:32:43Z

Merge activity

Mar 2, 6:32 AM UTC: The merge label 'graphite: merge-when-ready' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Mar 2, 6:32 AM UTC: hyf0 added this pull request to the Graphite merge queue.
Mar 2, 6:44 AM UTC: Merged by the Graphite merge queue.

## Summary Wire up `rolldown_watcher` to fully replace the legacy watcher (`crates/rolldown/src/watch/`). - Deprecate `watch.notify` option and add `watch.watcher` with `usePolling` / `pollInterval` (flat options instead of nested notify struct) - Replace `setInterval` keep-alive hack with pending `waitForClose()` Promise - Move event dispatching from channel-based (`rx.recv()` loop) to trait-based (`WatcherEventHandler`) - Use `with_cached_bundle_experimental` for split-phase builds — register FS watches between scan and write so render-hook file changes are detected (see `meta/design/watch-mode.md` "Split-Phase Build") - Add kind consolidation during debounce (Create+Update→Create, Create+Delete→removed, Delete+Create→Update) — see `meta/design/watch-mode.md` "Kind Consolidation" - Simplify `WatcherEmitter` to a thin `emit()` dispatcher, move event decoding to `Watcher.createEventCallback()` - Add `BindingWatcherState` (Pending→Running→Closed) in NAPI binding layer --- I will fix reviews in separate PRs, this PR is too cumbersome to make changes ## Test plan - [x] `cargo test -p rolldown_watcher` — 17 unit tests pass - [x] `pnpm --filter rolldown-tests test:watcher` — 25 integration tests pass - [x] `just roll` 🤖 Generated with [Claude Code](https://claude.com/claude-code)

@IWANABETHATGUY

## [1.0.0-rc.7] - 2026-03-05 ⚡ Smarter Code Generation Defaults - DCE-only minification and smart constant inlining are now enabled by default - Produces cleaner, smaller output bundles without requiring explicit configuration 💡 LLM-Friendly Bundle Analyzer Reports - New markdown output format for the bundle analyzer plugin with bundle summaries, module graphs, dependency chains, and optimization suggestions - Optimization suggestions now also recommend using the entriesAware option when common chunks contain modules only reachable from specific entries ### 💥 BREAKING CHANGES - enable minify: 'dce-only' by default (#8465) by @IWANABETHATGUY - settings `inlineConst: { mode: 'smart', pass: 1}` by default (#8444) by @IWANABETHATGUY ### 🚀 Features - binding: add original getter to BindingMagicString (#8533) by @IWANABETHATGUY - native-magic-string: add `offset` property support (#8531) by @IWANABETHATGUY - add `output.strict` option to control `"use strict"` directive emission (#8489) by @Copilot - watch: expose `watcher.compareContentsForPolling` (#8526) by @hyf0 - watch: use new watcher to support watch mode (#8475) by @hyf0 - rust/watch: handle bulk-change (#8466) by @hyf0 - add LLM-friendly markdown output format to bundle analyzer plugin (#8242) by @IWANABETHATGUY ### 🐛 Bug Fixes - expose `plugins` on `NormalizedInputOptions` for `buildStart` hook (#8521) by @Copilot - only uppercase facade symbols in JSX preserve mode (#8519) by @IWANABETHATGUY - binding: export BindingResult in generated dts header (#8537) by @minsoo-web - pre-resolve paths option to avoid `invoke_sync` deadlock (#8518) by @IWANABETHATGUY - remove debug-only jsx_preset and UntranspiledSyntaxError (#8511) by @IWANABETHATGUY - apply `topLevelVar` to exported `const`/`let` declarations (#8507) by @IWANABETHATGUY - rolldown_plugin_vite_web_worker_post: avoid replacing `new.target` (#8488) by @sapphi-red - update copyright year to 2026 (#8486) by @maciekzygmunt ### 🚜 Refactor - rust: use Oxc's SymbolFlags::ConstVariable instead of custom IsConst flag (#8543) by @Dunqing - rust: remove FacadeScoping, use Scoping::create_symbol for facade symbols (#8540) by @Dunqing - rust/watch: remove hacky `reset_closed_for_watch_mode` (#8530) by @hyf0 - binding: return &str instead of String in filename() getter (#8534) by @IWANABETHATGUY - rust: remove old watch mode implementation (#8525) by @hyf0 - rust/watch: simply watch logic in the binding layer (#8516) by @hyf0 - rust/watch: tweak struct/function names (#8464) by @hyf0 ### 📚 Documentation - explain how external modules work in rolldown (#8457) by @sapphi-red - add some diagrams using graphviz (#8499) by @sapphi-red - use `vitepress-plugin-graphviz` (#8498) by @sapphi-red - list s390x/ppc64le prebuilt binaries (#8495) by @crusty-voidzero - fix error type for `RolldownBuild.generate` and others (#8490) by @sapphi-red ### ⚡ Performance - string_wizard: reduce allocations and add ASCII fast paths (#8541) by @IWANABETHATGUY - use IndexBitSet to replace IndexVec<XXXIdx, bool> for module/stmt inclusion tracking (#8503) by @IWANABETHATGUY - plugin: use IndexBitSet to optimize skipped plugins checking (#8497) by @ShroXd - rust/tla: skip compute_tla if there is no module use TLA (#8487) by @ShroXd ### 🧪 Testing - node/watch: make watch tests run in concurrent and retry-able (#8512) by @hyf0 - add test case for static flag tree-shaking (#8476) by @IWANABETHATGUY - migrate post-banner sourcemap-with-shebang to Rust (#8477) by @Copilot ### ⚙️ Miscellaneous Tasks - vscode: `formatOnSave` for markdown files using oxc formatter (#8536) by @minsoo-web - deps: update test262 submodule for tests (#8528) by @sapphi-red - remove `retry` workaround from output paths test fixtures (#8520) by @Copilot - docs: add Shuyuan Wang (h-a-n-a) and remove from acknowledgements (#8509) by @Copilot - consolidate top_level_var test cases using configVariants (#8508) by @IWANABETHATGUY - add s390x and ppc64le linux gnu targets (#8493) by @Brooooooklyn ### ◀️ Revert - fix(rolldown): increase tokio blocking threads size for watch mode (#8517) by @hyf0 ### ❤️ New Contributors * @minsoo-web made their first contribution in [#8536](#8536) * @crusty-voidzero made their first contribution in [#8495](#8495) * @maciekzygmunt made their first contribution in [#8486](#8486) Co-authored-by: shulaoda <165626830+shulaoda@users.noreply.github.com>

hyf0 mentioned this pull request Feb 26, 2026

feat(rust/watch): handle bulk-change #8466

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test(node/watch): make watch tests run in concurrent and retry-able #8512

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refactor(rust/watch): simply watch logic in the binding layer #8516

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This was referenced Mar 2, 2026

revert: fix(rolldown): increase tokio blocking threads size for watch mode #8517

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refactor(rust): remove old watch mode implementation #8525

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feat(watch): expose watcher.compareContentsForPolling #8526

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This was referenced Mar 4, 2026

release: v1.0.0-rc.7 #8539

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release: v1.0.0-rc.7 #8547

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