events: avoid retaining removed event names by mcollina · Pull Request #64475 · nodejs/node

mcollina · 2026-07-13T16:17:26Z

Follow-up to #64373.

That change retained removed listener keys with an undefined value for all EventEmitter instances. With unstructured event names, _events would therefore grow without bound.

This restores shape mode so preallocated emitters can retain their fixed keys while ordinary emitters delete dynamic keys or reset the events object. It also adds a regression test that adds and removes 100 unique event names and verifies they are not retained.

github-actions · 2026-07-13T16:17:59Z

Fast-track has been requested by @mcollina. Please 👍 to approve.

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: nodejs#64373 Signed-off-by: Matteo Collina <hello@matteocollina.com>

nodejs-github-bot · 2026-07-13T17:02:45Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74785/

codecov · 2026-07-13T17:54:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (384d7a4) to head (ac80a3b).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #64475 +/- ##
=======================================
Coverage 90.21% 90.22% =======================================
Files 741 741 Lines 241608 241615 +7 Branches 45534 45523 -11 =======================================
+ Hits 217972 217987 +15 - Misses 15154 15158 +4 + Partials 8482 8470 -12

Files with missing lines	Coverage Δ
lib/events.js	`99.60% <100.00%> (+<0.01%)`	⬆️

... and 20 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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nodejs-github-bot · 2026-07-13T23:32:40Z

Landed in 35115c0

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: #64373 Signed-off-by: Matteo Collina <hello@matteocollina.com> PR-URL: #64475 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: James M Snell <jasnell@gmail.com>

mcollina · 2026-07-13T16:17:26Z

Follow-up to #64373.

That change retained removed listener keys with an undefined value for all EventEmitter instances. With unstructured event names, _events would therefore grow without bound.

This restores shape mode so preallocated emitters can retain their fixed keys while ordinary emitters delete dynamic keys or reset the events object. It also adds a regression test that adds and removes 100 unique event names and verifies they are not retained.

github-actions · 2026-07-13T16:17:59Z

Fast-track has been requested by @mcollina. Please 👍 to approve.

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: nodejs#64373 Signed-off-by: Matteo Collina <hello@matteocollina.com>

nodejs-github-bot · 2026-07-13T17:02:45Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74785/

codecov · 2026-07-13T17:54:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (384d7a4) to head (ac80a3b).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #64475 +/- ##
=======================================
Coverage 90.21% 90.22% =======================================
Files 741 741 Lines 241608 241615 +7 Branches 45534 45523 -11 =======================================
+ Hits 217972 217987 +15 - Misses 15154 15158 +4 + Partials 8482 8470 -12

Files with missing lines	Coverage Δ
lib/events.js	`99.60% <100.00%> (+<0.01%)`	⬆️

... and 20 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 · 2026-07-13T23:32:40Z

Landed in 35115c0

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: #64373 Signed-off-by: Matteo Collina <hello@matteocollina.com> PR-URL: #64475 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: James M Snell <jasnell@gmail.com>

mcollina · 2026-07-13T16:17:26Z

Follow-up to #64373.

That change retained removed listener keys with an undefined value for all EventEmitter instances. With unstructured event names, _events would therefore grow without bound.

This restores shape mode so preallocated emitters can retain their fixed keys while ordinary emitters delete dynamic keys or reset the events object. It also adds a regression test that adds and removes 100 unique event names and verifies they are not retained.

github-actions · 2026-07-13T16:17:59Z

Fast-track has been requested by @mcollina. Please 👍 to approve.

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: nodejs#64373 Signed-off-by: Matteo Collina <hello@matteocollina.com>

nodejs-github-bot · 2026-07-13T17:02:45Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74785/

codecov · 2026-07-13T17:54:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (384d7a4) to head (ac80a3b).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #64475 +/- ##
=======================================
Coverage 90.21% 90.22% =======================================
Files 741 741 Lines 241608 241615 +7 Branches 45534 45523 -11 =======================================
+ Hits 217972 217987 +15 - Misses 15154 15158 +4 + Partials 8482 8470 -12

Files with missing lines	Coverage Δ
lib/events.js	`99.60% <100.00%> (+<0.01%)`	⬆️

... and 20 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 · 2026-07-13T23:32:40Z

Landed in 35115c0

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: #64373 Signed-off-by: Matteo Collina <hello@matteocollina.com> PR-URL: #64475 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: James M Snell <jasnell@gmail.com>

mcollina · 2026-07-13T16:17:26Z

Follow-up to #64373.

That change retained removed listener keys with an undefined value for all EventEmitter instances. With unstructured event names, _events would therefore grow without bound.

This restores shape mode so preallocated emitters can retain their fixed keys while ordinary emitters delete dynamic keys or reset the events object. It also adds a regression test that adds and removes 100 unique event names and verifies they are not retained.

github-actions · 2026-07-13T16:17:59Z

Fast-track has been requested by @mcollina. Please 👍 to approve.

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: nodejs#64373 Signed-off-by: Matteo Collina <hello@matteocollina.com>

nodejs-github-bot · 2026-07-13T17:02:45Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74785/

codecov · 2026-07-13T17:54:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (384d7a4) to head (ac80a3b).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #64475 +/- ##
=======================================
Coverage 90.21% 90.22% =======================================
Files 741 741 Lines 241608 241615 +7 Branches 45534 45523 -11 =======================================
+ Hits 217972 217987 +15 - Misses 15154 15158 +4 + Partials 8482 8470 -12

Files with missing lines	Coverage Δ
lib/events.js	`99.60% <100.00%> (+<0.01%)`	⬆️

... and 20 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 · 2026-07-13T23:32:40Z

Landed in 35115c0

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: #64373 Signed-off-by: Matteo Collina <hello@matteocollina.com> PR-URL: #64475 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: James M Snell <jasnell@gmail.com>

mcollina · 2026-07-13T16:17:26Z

Follow-up to #64373.

That change retained removed listener keys with an undefined value for all EventEmitter instances. With unstructured event names, _events would therefore grow without bound.

This restores shape mode so preallocated emitters can retain their fixed keys while ordinary emitters delete dynamic keys or reset the events object. It also adds a regression test that adds and removes 100 unique event names and verifies they are not retained.

github-actions · 2026-07-13T16:17:59Z

Fast-track has been requested by @mcollina. Please 👍 to approve.

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: nodejs#64373 Signed-off-by: Matteo Collina <hello@matteocollina.com>

nodejs-github-bot · 2026-07-13T17:02:45Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74785/

codecov · 2026-07-13T17:54:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (384d7a4) to head (ac80a3b).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #64475 +/- ##
=======================================
Coverage 90.21% 90.22% =======================================
Files 741 741 Lines 241608 241615 +7 Branches 45534 45523 -11 =======================================
+ Hits 217972 217987 +15 - Misses 15154 15158 +4 + Partials 8482 8470 -12

Files with missing lines	Coverage Δ
lib/events.js	`99.60% <100.00%> (+<0.01%)`	⬆️

... and 20 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 · 2026-07-13T23:32:40Z

Landed in 35115c0

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: #64373 Signed-off-by: Matteo Collina <hello@matteocollina.com> PR-URL: #64475 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: James M Snell <jasnell@gmail.com>

mcollina · 2026-07-13T16:17:26Z

Follow-up to #64373.

That change retained removed listener keys with an undefined value for all EventEmitter instances. With unstructured event names, _events would therefore grow without bound.

This restores shape mode so preallocated emitters can retain their fixed keys while ordinary emitters delete dynamic keys or reset the events object. It also adds a regression test that adds and removes 100 unique event names and verifies they are not retained.

github-actions · 2026-07-13T16:17:59Z

Fast-track has been requested by @mcollina. Please 👍 to approve.

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: nodejs#64373 Signed-off-by: Matteo Collina <hello@matteocollina.com>

nodejs-github-bot · 2026-07-13T17:02:45Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74785/

codecov · 2026-07-13T17:54:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (384d7a4) to head (ac80a3b).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #64475 +/- ##
=======================================
Coverage 90.21% 90.22% =======================================
Files 741 741 Lines 241608 241615 +7 Branches 45534 45523 -11 =======================================
+ Hits 217972 217987 +15 - Misses 15154 15158 +4 + Partials 8482 8470 -12

Files with missing lines	Coverage Δ
lib/events.js	`99.60% <100.00%> (+<0.01%)`	⬆️

... and 20 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 · 2026-07-13T23:32:40Z

Landed in 35115c0

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: #64373 Signed-off-by: Matteo Collina <hello@matteocollina.com> PR-URL: #64475 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: James M Snell <jasnell@gmail.com>

mcollina · 2026-07-13T16:17:26Z

Follow-up to #64373.

That change retained removed listener keys with an undefined value for all EventEmitter instances. With unstructured event names, _events would therefore grow without bound.

This restores shape mode so preallocated emitters can retain their fixed keys while ordinary emitters delete dynamic keys or reset the events object. It also adds a regression test that adds and removes 100 unique event names and verifies they are not retained.

github-actions · 2026-07-13T16:17:59Z

Fast-track has been requested by @mcollina. Please 👍 to approve.

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: nodejs#64373 Signed-off-by: Matteo Collina <hello@matteocollina.com>

nodejs-github-bot · 2026-07-13T17:02:45Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74785/

codecov · 2026-07-13T17:54:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (384d7a4) to head (ac80a3b).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #64475 +/- ##
=======================================
Coverage 90.21% 90.22% =======================================
Files 741 741 Lines 241608 241615 +7 Branches 45534 45523 -11 =======================================
+ Hits 217972 217987 +15 - Misses 15154 15158 +4 + Partials 8482 8470 -12

Files with missing lines	Coverage Δ
lib/events.js	`99.60% <100.00%> (+<0.01%)`	⬆️

... and 20 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 · 2026-07-13T23:32:40Z

Landed in 35115c0

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: #64373 Signed-off-by: Matteo Collina <hello@matteocollina.com> PR-URL: #64475 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: James M Snell <jasnell@gmail.com>

mcollina · 2026-07-13T16:17:26Z

Follow-up to #64373.

That change retained removed listener keys with an undefined value for all EventEmitter instances. With unstructured event names, _events would therefore grow without bound.

This restores shape mode so preallocated emitters can retain their fixed keys while ordinary emitters delete dynamic keys or reset the events object. It also adds a regression test that adds and removes 100 unique event names and verifies they are not retained.

github-actions · 2026-07-13T16:17:59Z

Fast-track has been requested by @mcollina. Please 👍 to approve.

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: nodejs#64373 Signed-off-by: Matteo Collina <hello@matteocollina.com>

nodejs-github-bot · 2026-07-13T17:02:45Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74785/

codecov · 2026-07-13T17:54:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.22%. Comparing base (384d7a4) to head (ac80a3b).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #64475 +/- ##
=======================================
Coverage 90.21% 90.22% =======================================
Files 741 741 Lines 241608 241615 +7 Branches 45534 45523 -11 =======================================
+ Hits 217972 217987 +15 - Misses 15154 15158 +4 + Partials 8482 8470 -12

Files with missing lines	Coverage Δ
lib/events.js	`99.60% <100.00%> (+<0.01%)`	⬆️

... and 20 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 · 2026-07-13T23:32:40Z

Landed in 35115c0

Restore shape mode for preallocated EventEmitters while deleting dynamic names from ordinary EventEmitters. Keeping every removed name as an undefined property causes unbounded memory growth when event names are unstructured. Refs: #64373 Signed-off-by: Matteo Collina <hello@matteocollina.com> PR-URL: #64475 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: James M Snell <jasnell@gmail.com>

mcollina requested a review from ronag July 13, 2026 16:17

nodejs-github-bot added events Issues and PRs related to EventEmitter and the events module. needs-ci PRs that need a full CI run. labels Jul 13, 2026

mcollina added the fast-track PRs proposed for a shorter-than-standard waiting period before landing. label Jul 13, 2026

ronag approved these changes Jul 13, 2026
View reviewed changes

jasnell approved these changes Jul 13, 2026
View reviewed changes

mcollina force-pushed the fix-event-emitter-unstructured-names branch from f0421ba to ac80a3bCompare July 13, 2026 16:20

ronag approved these changes Jul 13, 2026
View reviewed changes

mcollina added the request-ci Add this label to start a Jenkins CI on a PR. label Jul 13, 2026

github-actionsBot removed the request-ci Add this label to start a Jenkins CI on a PR. label Jul 13, 2026

mcollina added the commit-queue PRs queued for automated landing through the Commit Queue. label Jul 13, 2026

nodejs-github-bot removed the commit-queue PRs queued for automated landing through the Commit Queue. label Jul 13, 2026

nodejs-github-bot merged commit 35115c0 into nodejs:mainJul 13, 2026
70 checks passed

github-actionsBot mentioned this pull request Jul 14, 2026
[Vulnerability] nodejs/node: Denial of Service (Unbounded Memory Growth / Memory Leak) spaceraccoon/vulnerability-spoiler-alert#320
Open

github-actionsBot mentioned this pull request Jul 21, 2026
2026-07-22, Version 26.6.0 (Current) #64655
Merged

github-actionsBot mentioned this pull request Aug 21, 2026
2026-08-26, Version 24.20.0 'Krypton' (LTS) #65461
Merged