repl: use inspector over vm#64034

avivkeller · 2026-06-20T21:46:39Z

This PR switches the REPL from node:vm to node:inspector, moving it from a synchronous to an asynchronous evaluator. This brings the following improvements:

Top-level await is now natively supported by the inspector, so --no-experimental-repl-await is no longer accepted. This also resolves a known limitation where TLA would invalidate the lexical scoping of const declarations.
Static imports such as import ... from '...' are now transformed into real dynamic imports and executed, rather than throwing Cannot use import statement outside a module with a hint to rewrite the import manually. This isn't strictly required by removing node:vm, but the change makes it easier. I can split this into a separate PR if preferred.
Several node:vm issues are resolved (see the list below), and users can now attach process listeners without breaking the REPL.
Errors are more detailed: for example, showing the specific line in a .load-ed file where an error was thrown.

This is a semver-major change; see the reasons listed in the notable changes section.

Removed Tests

addons/repl-domain-abort, parallel/test-repl-domain.js: We no longer rely on the domain module, so testing it is no longer needed.
- parallel/test-repl-no-terminal-restore-process-listeners.js: An extension of the above — we no longer modify the ability to set process listeners.
- parallel/test-repl-uncaught-exception-async.js / parallel/test-repl-uncaught-exception.js / parallel/test-repl-tab-complete-nested-repls.js: An extension of the above; this test case no longer throws an error.
known_issues/test-repl-require-context.js: This known issue has been resolved.
parallel/test-repl-top-level-await.js: No need to test TLA — it's supported natively by the inspector.
- parallel/test-repl-preprocess-top-level-await.js: An extension of the above; the REPL no longer pre-processes top-level await.
parallel/test-repl-preview-without-inspector.js: The REPL no longer works without the inspector.
parallel/test-util-sigint-watchdog.js: This tested code that has been removed as part of this migration.
pseudo-tty/repl-dumb-tty.js: There's currently no way to conditionally run these tests (run only when inspector is available).

Fixes: #61390
Fixes: #63126
Fixes: #38503
Fixes: #39387 (Closes #39392)
Fixes: #37445
Fixes: #38145
Fixes: #33369
Fixes: #48131
Fixes: #8309
Fixes: #39689
Fixes: #18931

Notable Change

The REPL has been re-implemented on top of the V8 Inspector (node:inspector) rather than node:vm. This moves the REPL from a synchronous to an asynchronous evaluator and resolves long-standing design quirks that stemmed from the vm-based design:

Because the inspector natively supports top-level await, the --no-experimental-repl-await flag is no longer accepted, and top-level await no longer corrupts the lexical scoping of const/let declarations. Additionally, statements that would normally return a Promise are now awaited until they settle.
Lines such as import { readFile } from 'node:fs/promises' are now transformed into real dynamic imports and executed.
_ and _error are available even in REPLs with a modified context.
Users can now add listeners (e.g. uncaughtException) without disrupting evaluation.
Throwing inside queueMicrotask/timer callbacks, and vm async timeouts, no longer take down the process.
Certain side-effect free Proxy's, Getters, and other non-static properties can be tab/auto-completed.
And more

Breaking changes

In addition to the removal of --no-experimental-repl-await and similar await changes noted above:

Because errors now surface through the inspector, their output (including the added detail) can differ from previous releases. Code or tests that match on exact REPL error or stack-trace text may need to be updated.
The caret/offset indicator that pointed at the precise location of a SyntaxError is no longer emitted in the main REPL; this information is still available programmatically in the stack trace.
V8's Inspector does not carry RegExp matches over to the global object across multiple evaluations.

nodejs-github-bot · 2026-06-20T21:46:44Z

Review requested:

@nodejs/config

avivkeller · 2026-06-22T00:08:54Z

cc @nodejs/repl @nodejs/inspector

github-actions · 2026-06-22T00:22:57Z

The notable-change PRs with changes that should be highlighted in changelogs. label has been added by @avivkeller.

Please suggest a text for the release notes if you'd like to include a more detailed summary, then proceed to update the PR description with the text or a link to the notable change suggested text comment. Otherwise, the commit will be placed in the Other Notable Changes section.

nodejs-github-bot · 2026-06-23T02:16:53Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74373/

nodejs-github-bot · 2026-06-23T07:13:11Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74377/

qwitwa · 2026-06-24T06:11:29Z

Does this change make tab-completions side-effect free in all cases?
(I ended up here after clicking through completion side-effect issues)
I see regex and generator side effects in the linked issues; my case was with dax's $ tag function, where

await $`echo hello`.sometext

was printing hello whilst tab completing.

avivkeller · 2026-06-24T11:28:21Z

Hi @qwitwa! Unfortunately, that specific case is not resolved by this PR. Although, that might be an issue with V8, since the REPL relies on CDP's throwOnSideEffect, which determines $ as side-effect free (even though, apparently, it's not)

avivkeller · 2026-06-26T16:29:58Z

Bump @nodejs/repl @nodejs/vm @nodejs/inspector

dario-piotrowicz

I haven't touched this code in quite and the changes here are quite significat, but generally the changes do look good to me

I also spot checked a few test files and everything there seems to generally make sense to me

I think this PR should definitely also get some other reviews besides mine before landing, in particular if @BridgeAR could have a look that'd be great I think 🫶

nodejs-github-bot · 2026-07-11T17:42:38Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74742/

nodejs-github-bot · 2026-07-12T04:05:12Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74745/

Signed-off-by: Aviv Keller <me@aviv.sh>

nodejs-github-bot · 2026-07-12T22:11:31Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74769/

avivkeller · 2026-07-12T22:19:51Z

IIRC semver-major requires at least 2 TSC approvals, so cc @nodejs/TSC

codecov · 2026-07-12T23:42:39Z

Codecov Report

❌ Patch coverage is 86.19379% with 218 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.14%. Comparing base (b4c7be3) to head (6a2edae).
⚠️ Report is 47 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/repl/transform.js	58.49%	66 Missing ⚠️
lib/internal/repl/completion.js	90.97%	44 Missing and 7 partials ⚠️
src/inspector_js_api.cc	42.42%	34 Missing and 4 partials ⚠️
lib/internal/repl/inspector.js	91.16%	21 Missing and 1 partial ⚠️
lib/internal/repl/eval.js	93.39%	15 Missing ⚠️
lib/internal/repl/utils.js	92.10%	10 Missing and 2 partials ⚠️
lib/repl.js	91.54%	12 Missing ⚠️
src/node_contextify.cc	88.88%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #64034      +/-   ##
==========================================
- Coverage   90.23%   90.14%   -0.09%     
==========================================
  Files         741      741              
  Lines      241604   241917     +313     
  Branches    45520    45535      +15     
==========================================
+ Hits       218010   218082      +72     
- Misses      15120    15348     +228     
- Partials     8474     8487      +13

Files with missing lines	Coverage Δ
lib/internal/errors.js	`97.90% <ø> (+0.19%)`	⬆️
lib/internal/repl/history.js	`93.62% <100.00%> (ø)`
src/node_options.cc	`76.70% <ø> (+0.07%)`	⬆️
src/node_options.h	`98.00% <ø> (-0.01%)`	⬇️
src/node_contextify.cc	`81.81% <88.88%> (-0.26%)`	⬇️
lib/internal/repl/utils.js	`96.92% <92.10%> (+0.53%)`	⬆️
lib/repl.js	`92.37% <91.54%> (-1.64%)`	⬇️
lib/internal/repl/eval.js	`93.39% <93.39%> (ø)`
lib/internal/repl/inspector.js	`91.16% <91.16%> (ø)`
src/inspector_js_api.cc	`76.99% <42.42%> (-8.07%)`	⬇️
... and 2 more

... and 61 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

nodejs-github-bot · 2026-07-13T00:04:02Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74770/

**Description:** Adds an independent Rust/WebAssembly binding at `bindings/binding_nodejs_support_wasm`, published as `@swc/nodejs-support-wasm`. The package has its own Rust crate, sources, build scripts, tests, README, Cargo entry, and npm workspace entry. It does not build from `binding_typescript_wasm` and does not add features or exports to the existing `@swc/wasm-typescript` or `@swc/wasm-typescript-esm` packages. The new CommonJS package embeds its wasm binary and exposes these APIs at the top level: - `transform` - `transformSync` - `transformModuleSyntax` - `getFirstExpression` - `isValidSyntax` - `isRecoverableError` It also exports the related `Options`, `TransformOutput`, and `ModuleSyntaxTransformOutput` TypeScript types. The npm publish matrix, wasm CI matrix, release versioning, Cargo lockfile, and pnpm lockfile now reference the standalone `binding_nodejs_support_wasm` crate. Validation performed: - `git submodule update --init --recursive` - `cargo fmt --all -- --check` - `cargo test -p binding_typescript_wasm -p binding_nodejs_support_wasm` - `cargo clippy --all --all-targets -- -D warnings` - `(cd bindings/binding_nodejs_support_wasm && ./scripts/test.sh)` - `(cd bindings/binding_typescript_wasm && ./scripts/test.sh)` - `(cd bindings/binding_core_wasm && ./scripts/test.sh)` - `(cd bindings/binding_minifier_wasm && ./scripts/test.sh)` - `(cd bindings/binding_es_ast_viewer && ./scripts/test.sh)` - `(cd bindings/binding_nodejs_support_wasm/pkg && npm pack --dry-run --json)` - `pnpm install --frozen-lockfile --ignore-scripts` - `go run github.com/rhysd/actionlint/cmd/actionlint@latest .github/workflows/CI.yml .github/workflows/publish-npm-package.yml` **BREAKING CHANGE:** None. The existing TypeScript wasm packages and their public APIs are unchanged. **Related issue (if exists):** - Supports nodejs/node#64034 - Follow-up context from #11973

mcollina

Lgtm

avivkeller · 2026-07-16T19:42:10Z

Bump!

panva

LGTM

nodejs-github-bot · 2026-07-18T16:25:18Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74880/

avivkeller marked this pull request as draft June 20, 2026 21:46

nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. lib / src Issues and PRs related to general changes in the lib or src directory. needs-ci PRs that need a full CI run. labels Jun 20, 2026

addaleax added the semver-major PRs that contain breaking changes and should be released in the next major version. label Jun 20, 2026

avivkeller added the repl Issues and PRs related to the REPL subsystem. label Jun 20, 2026

avivkeller force-pushed the repl-inspector branch 4 times, most recently from 9fdad96 to 56ebb41 Compare June 21, 2026 23:58

avivkeller changed the title ~~[WIP] repl: use inspector over vm~~ repl: use inspector over vm Jun 22, 2026

avivkeller marked this pull request as ready for review June 22, 2026 00:03

avivkeller force-pushed the repl-inspector branch 2 times, most recently from 3f34721 to d7534b9 Compare June 22, 2026 00:07

avivkeller added the notable-change PRs with changes that should be highlighted in changelogs. label Jun 22, 2026

avivkeller force-pushed the repl-inspector branch 2 times, most recently from 012ec64 to e428a2e Compare June 22, 2026 20:28

avivkeller added the commit-queue-squash Add this label to instruct the Commit Queue to squash all the PR commits into the first one. label Jun 23, 2026

avivkeller force-pushed the repl-inspector branch from 33e1f17 to a949698 Compare June 23, 2026 00:59

avivkeller added the review wanted PRs that need reviews. label Jun 26, 2026

avivkeller force-pushed the repl-inspector branch from a949698 to ff79eed Compare June 27, 2026 21:45

This comment was marked as off-topic.

Sign in to view

dario-piotrowicz approved these changes Jul 10, 2026

View reviewed changes

Comment thread lib/internal/repl/eval.js

avivkeller added author ready PRs that have at least one approval, no pending requests for changes, and a CI started. request-ci Add this label to start a Jenkins CI on a PR. labels Jul 11, 2026

github-actions Bot removed the request-ci Add this label to start a Jenkins CI on a PR. label Jul 11, 2026

avivkeller requested a review from BridgeAR July 11, 2026 22:49

repl: use inspector over vm

4312021

Signed-off-by: Aviv Keller <me@aviv.sh>

avivkeller force-pushed the repl-inspector branch from 6b050ce to 4312021 Compare July 12, 2026 22:07

avivkeller removed the commit-queue-squash Add this label to instruct the Commit Queue to squash all the PR commits into the first one. label Jul 12, 2026

mcollina approved these changes Jul 13, 2026

View reviewed changes

avivkeller added 3 commits July 13, 2026 18:03

fixup!

3c6b505

fixup!

e33ad2e

fixup!

4cff544

avivkeller mentioned this pull request Jul 14, 2026

repl: add syntax highlighting, auto-indentation, and signature hints #64443

Open

avivkeller added 2 commits July 17, 2026 17:08

fixup! remove file from testing

6a2edae

fixup!

3b97a63

avivkeller requested a review from panva July 18, 2026 15:58

panva approved these changes Jul 18, 2026

View reviewed changes

panva added the request-ci Add this label to start a Jenkins CI on a PR. label Jul 18, 2026

github-actions Bot removed the request-ci Add this label to start a Jenkins CI on a PR. label Jul 18, 2026

avivkeller added 2 commits July 18, 2026 09:27

fixup!

f7bfe2a

fixup!

b000505

Uh oh!

Uh oh!

Conversation

avivkeller commented Jun 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Removed Tests

Notable Change

Breaking changes

Uh oh!

nodejs-github-bot commented Jun 20, 2026

Uh oh!

avivkeller commented Jun 22, 2026

Uh oh!

github-actions Bot commented Jun 22, 2026

Uh oh!

nodejs-github-bot commented Jun 23, 2026

Uh oh!

nodejs-github-bot commented Jun 23, 2026

Uh oh!

qwitwa commented Jun 24, 2026

Uh oh!

avivkeller commented Jun 24, 2026

Uh oh!

avivkeller commented Jun 26, 2026

Uh oh!

This comment was marked as off-topic.

dario-piotrowicz left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

nodejs-github-bot commented Jul 11, 2026

Uh oh!

nodejs-github-bot commented Jul 12, 2026

Uh oh!

nodejs-github-bot commented Jul 12, 2026

Uh oh!

avivkeller commented Jul 12, 2026

Uh oh!

codecov Bot commented Jul 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

nodejs-github-bot commented Jul 13, 2026

Uh oh!

mcollina left a comment

Choose a reason for hiding this comment

Uh oh!

avivkeller commented Jul 16, 2026

Uh oh!

panva left a comment

Choose a reason for hiding this comment

Uh oh!

nodejs-github-bot commented Jul 18, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

8 participants

avivkeller commented Jun 20, 2026 •

edited

Loading

codecov Bot commented Jul 12, 2026 •

edited

Loading