repl: use inspector over vm by avivkeller · Pull Request #64034 · nodejs/node

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: #64523
Closes: #64534

Fixes: #39387
Closes: #39392

Fixes: #61390
Fixes: #63126
Fixes: #38503
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

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 85.42560% with 238 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.14%. Comparing base (b4c7be3) to head (e90cd83).
⚠️ Report is 52 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/repl/transform.js	54.06%	79 Missing ⚠️
lib/internal/repl/completion.js	90.44%	47 Missing and 7 partials ⚠️
src/inspector_js_api.cc	39.34%	34 Missing and 3 partials ⚠️
lib/internal/repl/inspector.js	90.80%	24 Missing and 1 partial ⚠️
lib/internal/repl/eval.js	93.16%	16 Missing ⚠️
lib/repl.js	91.77%	13 Missing ⚠️
lib/internal/repl/utils.js	92.10%	10 Missing and 2 partials ⚠️
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   241972     +368     
  Branches    45520    45538      +18     
==========================================
+ Hits       218010   218128     +118     
- Misses      15120    15357     +237     
- 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	`81.64% <88.88%> (-0.42%)`	⬇️
lib/internal/repl/utils.js	`96.92% <92.10%> (+0.53%)`	⬆️
lib/repl.js	`92.92% <91.77%> (-1.09%)`	⬇️
lib/internal/repl/eval.js	`93.16% <93.16%> (ø)`
lib/internal/repl/inspector.js	`90.80% <90.80%> (ø)`
src/inspector_js_api.cc	`77.01% <39.34%> (-8.04%)`	⬇️
... and 2 more

... and 59 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/

nodejs-github-bot · 2026-07-18T17:54:29Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74881/

mcollina

lgtm

nodejs-github-bot · 2026-07-18T19:40:17Z

Commit Queue failed

- Loading data for nodejs/node/pull/64034
✔  Done loading data for nodejs/node/pull/64034
----------------------------------- PR info ------------------------------------
Title      repl: use inspector over vm (#64034)
Author     Aviv Keller <me@aviv.sh> (@avivkeller)
Branch     avivkeller:repl-inspector -> nodejs:main
Labels     c++, repl, semver-major, lib / src, notable-change, author ready, needs-ci, review wanted, commit-queue-squash
Commits    9
 - repl: use inspector over vm
 - fixup!
 - fixup!
 - fixup!
 - fixup! remove file from testing
 - fixup!
 - fixup!
 - fixup!
 - fixup!
Committers 2
 - avivkeller <me@aviv.sh>
 - GitHub <noreply@github.com>
PR-URL: https://github.com/nodejs/node/pull/64034
Fixes: https://github.com/nodejs/node/issues/64523
Fixes: https://github.com/nodejs/node/pull/64534
Fixes: https://github.com/nodejs/node/issues/39387
Fixes: https://github.com/nodejs/node/pull/39392
Fixes: https://github.com/nodejs/node/issues/61390
Fixes: https://github.com/nodejs/node/issues/63126
Fixes: https://github.com/nodejs/node/issues/38503
Fixes: https://github.com/nodejs/node/issues/37445
Fixes: https://github.com/nodejs/node/issues/38145
Fixes: https://github.com/nodejs/node/issues/33369
Fixes: https://github.com/nodejs/node/issues/48131
Fixes: https://github.com/nodejs/node/issues/8309
Fixes: https://github.com/nodejs/node/issues/39689
Fixes: https://github.com/nodejs/node/issues/18931
Reviewed-By: Dario Piotrowicz <dario.piotrowicz@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>
------------------------------ Generated metadata ------------------------------
PR-URL: https://github.com/nodejs/node/pull/64034
Fixes: https://github.com/nodejs/node/issues/64523
Fixes: https://github.com/nodejs/node/pull/64534
Fixes: https://github.com/nodejs/node/issues/39387
Fixes: https://github.com/nodejs/node/pull/39392
Fixes: https://github.com/nodejs/node/issues/61390
Fixes: https://github.com/nodejs/node/issues/63126
Fixes: https://github.com/nodejs/node/issues/38503
Fixes: https://github.com/nodejs/node/issues/37445
Fixes: https://github.com/nodejs/node/issues/38145
Fixes: https://github.com/nodejs/node/issues/33369
Fixes: https://github.com/nodejs/node/issues/48131
Fixes: https://github.com/nodejs/node/issues/8309
Fixes: https://github.com/nodejs/node/issues/39689
Fixes: https://github.com/nodejs/node/issues/18931
Reviewed-By: Dario Piotrowicz <dario.piotrowicz@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>
--------------------------------------------------------------------------------
   ℹ  This PR was created on Sat, 20 Jun 2026 21:46:39 GMT
   ✔  Approvals: 3
   ✔  - Dario Piotrowicz (@dario-piotrowicz): https://github.com/nodejs/node/pull/64034#pullrequestreview-4675448876
   ✔  - Matteo Collina (@mcollina) (TSC): https://github.com/nodejs/node/pull/64034#pullrequestreview-4729043601
   ✔  - Filip Skokan (@panva) (TSC): https://github.com/nodejs/node/pull/64034#pullrequestreview-4728817049
   ✔  Last GitHub CI successful
   ℹ  Last Full PR CI on 2026-07-18T17:54:29Z: https://ci.nodejs.org/job/node-test-pull-request/74881/
- Querying data for job/node-test-pull-request/74881/
✔  Build data downloaded
   ✔  Last Jenkins CI successful
--------------------------------------------------------------------------------
   ✔  No git cherry-pick in progress
   ✔  No git am in progress
   ✔  No git rebase in progress
--------------------------------------------------------------------------------
- Bringing origin/main up to date...
From https://github.com/nodejs/node
 * branch                  main       -> FETCH_HEAD
✔  origin/main is now up-to-date
- Downloading patch for 64034
From https://github.com/nodejs/node
 * branch                  refs/pull/64034/merge -> FETCH_HEAD
✔  Fetched commits as 9df0e9b4d4a5..e90cd833579c
--------------------------------------------------------------------------------
Auto-merging doc/api/errors.md
Auto-merging lib/repl.js
[main a796734305] repl: use inspector over vm
 Author: avivkeller <me@aviv.sh>
 Date: Sat Jun 20 17:45:59 2026 -0400
 126 files changed, 3119 insertions(+), 4299 deletions(-)
 delete mode 100644 lib/internal/repl/await.js
 create mode 100644 lib/internal/repl/eval.js
 create mode 100644 lib/internal/repl/inspector.js
 create mode 100644 lib/internal/repl/transform.js
 delete mode 100644 test/addons/repl-domain-abort/binding.cc
 delete mode 100644 test/addons/repl-domain-abort/binding.gyp
 delete mode 100644 test/addons/repl-domain-abort/test.js
 delete mode 100644 test/fixtures/repl-tab-completion-nested-repls.js
 delete mode 100644 test/known_issues/test-repl-require-context.js
 delete mode 100644 test/parallel/test-repl-autolibs.js
 create mode 100644 test/parallel/test-repl-autolibs.mjs
 rename test/parallel/{test-repl-context.js => test-repl-context.mjs} (83%)
 delete mode 100644 test/parallel/test-repl-definecommand.js
 create mode 100644 test/parallel/test-repl-definecommand.mjs
 delete mode 100644 test/parallel/test-repl-domain.js
 rename test/parallel/{test-repl-editor.js => test-repl-editor.mjs} (78%)
 delete mode 100644 test/parallel/test-repl-function-definition-edge-case.js
 create mode 100644 test/parallel/test-repl-function-definition-edge-case.mjs
 rename test/parallel/{test-repl-inspector.js => test-repl-inspector.mjs} (64%)
 rename test/parallel/{test-repl-load-multiline-no-trailing-newline.js => test-repl-load-multiline-no-trailing-newline.mjs} (56%)
 rename test/parallel/{test-repl-load-multiline.js => test-repl-load-multiline.mjs} (52%)
 delete mode 100644 test/parallel/test-repl-no-terminal-restore-process-listeners.js
 delete mode 100644 test/parallel/test-repl-preprocess-top-level-await.js
 delete mode 100644 test/parallel/test-repl-pretty-custom-stack.js
 create mode 100644 test/parallel/test-repl-pretty-custom-stack.mjs
 delete mode 100644 test/parallel/test-repl-pretty-stack-custom-writer.js
 create mode 100644 test/parallel/test-repl-pretty-stack-custom-writer.mjs
 delete mode 100644 test/parallel/test-repl-pretty-stack.js
 create mode 100644 test/parallel/test-repl-pretty-stack.mjs
 delete mode 100644 test/parallel/test-repl-preview-newlines.js
 create mode 100644 test/parallel/test-repl-preview-newlines.mjs
 delete mode 100644 test/parallel/test-repl-preview-without-inspector.js
 rename test/parallel/{test-repl-preview.js => test-repl-preview.mjs} (65%)
 delete mode 100644 test/parallel/test-repl-recoverable.js
 create mode 100644 test/parallel/test-repl-recoverable.mjs
 delete mode 100644 test/parallel/test-repl-sigint-nested-eval.js
 delete mode 100644 test/parallel/test-repl-tab-complete-buffer.js
 create mode 100644 test/parallel/test-repl-tab-complete-buffer.mjs
 delete mode 100644 test/parallel/test-repl-tab-complete-nested-repls.js
 delete mode 100644 test/parallel/test-repl-top-level-await.js
 delete mode 100644 test/parallel/test-repl-uncaught-exception-async.js
 delete mode 100644 test/parallel/test-repl-uncaught-exception-standalone.js
 create mode 100644 test/parallel/test-repl-uncaught-exception-standalone.mjs
 delete mode 100644 test/parallel/test-repl-uncaught-exception.js
 delete mode 100644 test/parallel/test-repl-underscore.js
 create mode 100644 test/parallel/test-repl-underscore.mjs
 delete mode 100644 test/parallel/test-repl-use-global.js
 create mode 100644 test/parallel/test-repl-use-global.mjs
 delete mode 100644 test/parallel/test-util-sigint-watchdog.js
 delete mode 100644 test/pseudo-tty/repl-dumb-tty.js
 delete mode 100644 test/pseudo-tty/repl-dumb-tty.out
[main f5a0f14734] fixup!
 Author: avivkeller <me@aviv.sh>
 Date: Mon Jul 13 18:03:34 2026 -0700
 5 files changed, 64 insertions(+), 21 deletions(-)
 create mode 100644 test/parallel/test-repl-promise-gc.mjs
error: The following untracked working tree files would be overwritten by merge:
	output
Please move or remove them before you merge.
Aborting
fatal: cherry-pick failed
[main 065e945eaa] fixup!
 Author: avivkeller <me@aviv.sh>
 Date: Mon Jul 13 18:07:27 2026 -0700
 2 files changed, 4 insertions(+), 1 deletion(-)
   ✘  Failed to apply patches

https://github.com/nodejs/node/actions/runs/29658096987

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

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

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avivkeller added 3 commits July 13, 2026 18:03

fixup!

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avivkeller mentioned this pull request Jul 14, 2026

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

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avivkeller added 2 commits July 17, 2026 17:08

fixup! remove file from testing

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fixup!

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