Skip to content

Enable Fragment Ref flags across builds - #36026

Merged
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags
Mar 12, 2026
Merged

Enable Fragment Ref flags across builds#36026
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags

Conversation

@jackpope

Copy link
Copy Markdown
Collaborator

No description provided.

@react-sizebot

Copy link
Copy Markdown

Comparing: a74302c...5673298

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js+0.15%611.79 kB612.68 kB+0.15%108.12 kB108.28 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js+0.13%677.72 kB678.62 kB+0.13%119.08 kB119.23 kB
facebook-www/ReactDOM-prod.classic.js=697.67 kB697.67 kB=122.58 kB122.58 kB
facebook-www/ReactDOM-prod.modern.js=687.98 kB687.98 kB=120.96 kB120.96 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show
Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
react-native/implementations/ReactFabric-prod.js+0.32%389.28 kB390.51 kB+0.35%67.27 kB67.51 kB
react-native/implementations/ReactFabric-profiling.js+0.26%465.41 kB466.64 kB+0.30%78.28 kB78.52 kB
facebook-www/ReactTestRenderer-dev.modern.js+0.24%605.71 kB607.18 kB+0.14%97.64 kB97.77 kB
facebook-www/ReactTestRenderer-dev.classic.js+0.24%605.71 kB607.19 kB+0.14%97.64 kB97.77 kB

Generated by 🚫 dangerJS against 5673298

@jackpope
jackpope merged commit 1e31523 into react:mainMar 12, 2026
242 checks passed
@jackpope
jackpope deleted the fr-flags branch March 12, 2026 17:07
github-actionsBot pushed a commit that referenced this pull request Mar 12, 2026
jackpope pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants

@jackpope@react-sizebot@thegreatercurve
, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
Enable Fragment Ref flags across builds by jackpope · Pull Request #36026 · react/react · GitHub
Skip to content

Enable Fragment Ref flags across builds - #36026

Merged
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags
Mar 12, 2026
Merged

Enable Fragment Ref flags across builds#36026
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags

Conversation

@jackpope

Copy link
Copy Markdown
Collaborator

No description provided.

@react-sizebot

Copy link
Copy Markdown

Comparing: a74302c...5673298

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js+0.15%611.79 kB612.68 kB+0.15%108.12 kB108.28 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js+0.13%677.72 kB678.62 kB+0.13%119.08 kB119.23 kB
facebook-www/ReactDOM-prod.classic.js=697.67 kB697.67 kB=122.58 kB122.58 kB
facebook-www/ReactDOM-prod.modern.js=687.98 kB687.98 kB=120.96 kB120.96 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show
Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
react-native/implementations/ReactFabric-prod.js+0.32%389.28 kB390.51 kB+0.35%67.27 kB67.51 kB
react-native/implementations/ReactFabric-profiling.js+0.26%465.41 kB466.64 kB+0.30%78.28 kB78.52 kB
facebook-www/ReactTestRenderer-dev.modern.js+0.24%605.71 kB607.18 kB+0.14%97.64 kB97.77 kB
facebook-www/ReactTestRenderer-dev.classic.js+0.24%605.71 kB607.19 kB+0.14%97.64 kB97.77 kB

Generated by 🚫 dangerJS against 5673298

@jackpope
jackpope merged commit 1e31523 into react:mainMar 12, 2026
242 checks passed
@jackpope
jackpope deleted the fr-flags branch March 12, 2026 17:07
github-actionsBot pushed a commit that referenced this pull request Mar 12, 2026
jackpope pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants

@jackpope@react-sizebot@thegreatercurve
, 'i'); if (__m === '*' || __re.test(location.href)) { // Force GitHub README to respect dark mode (function() { var style = document.createElement('style'); style.textContent = ' .markdown-body { color-scheme: dark light; } .markdown-body pre { background: #161b22 !important; } .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; } .markdown-body table th, .markdown-body table td { border-color: #30363d !important; } .markdown-body img { background: #0d1117; } .markdown-body blockquote { border-left-color: #8b949e; } .markdown-body hr { border-color: #30363d; } '; document.head.appendChild(style); })(); } } catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ' Enable Fragment Ref flags across builds by jackpope · Pull Request #36026 · react/react · GitHub
Skip to content

Enable Fragment Ref flags across builds - #36026

Merged
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags
Mar 12, 2026
Merged

Enable Fragment Ref flags across builds#36026
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags

Conversation

@jackpope

Copy link
Copy Markdown
Collaborator

No description provided.

@react-sizebot

Copy link
Copy Markdown

Comparing: a74302c...5673298

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js+0.15%611.79 kB612.68 kB+0.15%108.12 kB108.28 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js+0.13%677.72 kB678.62 kB+0.13%119.08 kB119.23 kB
facebook-www/ReactDOM-prod.classic.js=697.67 kB697.67 kB=122.58 kB122.58 kB
facebook-www/ReactDOM-prod.modern.js=687.98 kB687.98 kB=120.96 kB120.96 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show
Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
react-native/implementations/ReactFabric-prod.js+0.32%389.28 kB390.51 kB+0.35%67.27 kB67.51 kB
react-native/implementations/ReactFabric-profiling.js+0.26%465.41 kB466.64 kB+0.30%78.28 kB78.52 kB
facebook-www/ReactTestRenderer-dev.modern.js+0.24%605.71 kB607.18 kB+0.14%97.64 kB97.77 kB
facebook-www/ReactTestRenderer-dev.classic.js+0.24%605.71 kB607.19 kB+0.14%97.64 kB97.77 kB

Generated by 🚫 dangerJS against 5673298

@jackpope
jackpope merged commit 1e31523 into react:mainMar 12, 2026
242 checks passed
@jackpope
jackpope deleted the fr-flags branch March 12, 2026 17:07
github-actionsBot pushed a commit that referenced this pull request Mar 12, 2026
jackpope pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants

@jackpope@react-sizebot@thegreatercurve
, 'i'); if (__m === '*' || __re.test(location.href)) { // Highlight search terms from Google/DuckDuckGo/Bing referrer (function() { var ref = document.referrer; var terms = []; if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) { var url = new URL(ref); var q = url.searchParams.get('q') || url.searchParams.get('p'); if (q) { terms = q.split(/\s+/).filter(function(t) { return t.length > 2; }); } } if (terms.length === 0) return; var style = document.createElement('style'); style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }'; document.head.appendChild(style); function highlight(node) { if (node.nodeType === 3) { // text node var text = node.textContent; var found = false; terms.forEach(function(term) { var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi'); if (regex.test(text)) { found = true; var frag = document.createDocumentFragment(); var parts = text.split(regex); parts.forEach(function(part, i) { if (i % 2 === 0) { frag.appendChild(document.createTextNode(part)); } else { var span = document.createElement('span'); span.className = 'userscript-highlight'; span.textContent = part; frag.appendChild(span); } }); node.parentNode.replaceChild(frag, node); } }); } else if (node.nodeType === 1 && node.childNodes) { // element var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT']; if (!skipTags.includes(node.tagName)) { Array.from(node.childNodes).forEach(highlight); } } } highlight(document.body); // Re-highlight on dynamic content var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1 || node.nodeType === 3) highlight(node); }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ' Enable Fragment Ref flags across builds by jackpope · Pull Request #36026 · react/react · GitHub
Skip to content

Enable Fragment Ref flags across builds - #36026

Merged
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags
Mar 12, 2026
Merged

Enable Fragment Ref flags across builds#36026
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags

Conversation

@jackpope

Copy link
Copy Markdown
Collaborator

No description provided.

@react-sizebot

Copy link
Copy Markdown

Comparing: a74302c...5673298

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js+0.15%611.79 kB612.68 kB+0.15%108.12 kB108.28 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js+0.13%677.72 kB678.62 kB+0.13%119.08 kB119.23 kB
facebook-www/ReactDOM-prod.classic.js=697.67 kB697.67 kB=122.58 kB122.58 kB
facebook-www/ReactDOM-prod.modern.js=687.98 kB687.98 kB=120.96 kB120.96 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show
Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
react-native/implementations/ReactFabric-prod.js+0.32%389.28 kB390.51 kB+0.35%67.27 kB67.51 kB
react-native/implementations/ReactFabric-profiling.js+0.26%465.41 kB466.64 kB+0.30%78.28 kB78.52 kB
facebook-www/ReactTestRenderer-dev.modern.js+0.24%605.71 kB607.18 kB+0.14%97.64 kB97.77 kB
facebook-www/ReactTestRenderer-dev.classic.js+0.24%605.71 kB607.19 kB+0.14%97.64 kB97.77 kB

Generated by 🚫 dangerJS against 5673298

@jackpope
jackpope merged commit 1e31523 into react:mainMar 12, 2026
242 checks passed
@jackpope
jackpope deleted the fr-flags branch March 12, 2026 17:07
github-actionsBot pushed a commit that referenced this pull request Mar 12, 2026
jackpope pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants

@jackpope@react-sizebot@thegreatercurve
, 'i'); if (__m === '*' || __re.test(location.href)) { // Strip utm_, fbclid, gclid, etc. from all links on page (function() { var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content', 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid', 'ref', 'ref_src', 'source', 'medium', 'campaign']; function cleanUrl(url) { try { var u = new URL(url, window.location.origin); var changed = false; trackingParams.forEach(function(p) { if (u.searchParams.has(p)) { u.searchParams.delete(p); changed = true; } }); return changed ? u.toString() : url; } catch (e) { return url; } } function cleanLinks() { document.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } cleanLinks(); var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1) { if (node.tagName === 'A') cleanLinks(); node.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + ' Enable Fragment Ref flags across builds by jackpope · Pull Request #36026 · react/react · GitHub
Skip to content

Enable Fragment Ref flags across builds - #36026

Merged
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags
Mar 12, 2026
Merged

Enable Fragment Ref flags across builds#36026
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags

Conversation

@jackpope

Copy link
Copy Markdown
Collaborator

No description provided.

@react-sizebot

Copy link
Copy Markdown

Comparing: a74302c...5673298

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js+0.15%611.79 kB612.68 kB+0.15%108.12 kB108.28 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js+0.13%677.72 kB678.62 kB+0.13%119.08 kB119.23 kB
facebook-www/ReactDOM-prod.classic.js=697.67 kB697.67 kB=122.58 kB122.58 kB
facebook-www/ReactDOM-prod.modern.js=687.98 kB687.98 kB=120.96 kB120.96 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show
Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
react-native/implementations/ReactFabric-prod.js+0.32%389.28 kB390.51 kB+0.35%67.27 kB67.51 kB
react-native/implementations/ReactFabric-profiling.js+0.26%465.41 kB466.64 kB+0.30%78.28 kB78.52 kB
facebook-www/ReactTestRenderer-dev.modern.js+0.24%605.71 kB607.18 kB+0.14%97.64 kB97.77 kB
facebook-www/ReactTestRenderer-dev.classic.js+0.24%605.71 kB607.19 kB+0.14%97.64 kB97.77 kB

Generated by 🚫 dangerJS against 5673298

@jackpope
jackpope merged commit 1e31523 into react:mainMar 12, 2026
242 checks passed
@jackpope
jackpope deleted the fr-flags branch March 12, 2026 17:07
github-actionsBot pushed a commit that referenced this pull request Mar 12, 2026
jackpope pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants

@jackpope@react-sizebot@thegreatercurve
, 'i'); if (__m === '*' || __re.test(location.href)) { // Auto-enable theater mode on YouTube (function() { function tryTheater() { var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]'); if (btn && !btn.classList.contains('activated')) { btn.click(); } } // Try immediately tryTheater(); // Try after navigation (SPA) var lastUrl = location.href; setInterval(function() { if (location.href !== lastUrl) { lastUrl = location.href; setTimeout(tryTheater, 500); } }, 1000); // Also try on player load var observer = new MutationObserver(tryTheater); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ' Enable Fragment Ref flags across builds by jackpope · Pull Request #36026 · react/react · GitHub
Skip to content

Enable Fragment Ref flags across builds - #36026

Merged
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags
Mar 12, 2026
Merged

Enable Fragment Ref flags across builds#36026
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags

Conversation

@jackpope

Copy link
Copy Markdown
Collaborator

No description provided.

@react-sizebot

Copy link
Copy Markdown

Comparing: a74302c...5673298

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js+0.15%611.79 kB612.68 kB+0.15%108.12 kB108.28 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js+0.13%677.72 kB678.62 kB+0.13%119.08 kB119.23 kB
facebook-www/ReactDOM-prod.classic.js=697.67 kB697.67 kB=122.58 kB122.58 kB
facebook-www/ReactDOM-prod.modern.js=687.98 kB687.98 kB=120.96 kB120.96 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show
Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
react-native/implementations/ReactFabric-prod.js+0.32%389.28 kB390.51 kB+0.35%67.27 kB67.51 kB
react-native/implementations/ReactFabric-profiling.js+0.26%465.41 kB466.64 kB+0.30%78.28 kB78.52 kB
facebook-www/ReactTestRenderer-dev.modern.js+0.24%605.71 kB607.18 kB+0.14%97.64 kB97.77 kB
facebook-www/ReactTestRenderer-dev.classic.js+0.24%605.71 kB607.19 kB+0.14%97.64 kB97.77 kB

Generated by 🚫 dangerJS against 5673298

@jackpope
jackpope merged commit 1e31523 into react:mainMar 12, 2026
242 checks passed
@jackpope
jackpope deleted the fr-flags branch March 12, 2026 17:07
github-actionsBot pushed a commit that referenced this pull request Mar 12, 2026
jackpope pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants

@jackpope@react-sizebot@thegreatercurve
, 'i'); if (__m === '*' || __re.test(location.href)) { // Remove or un-stick sticky/fixed headers that block content (function() { function unstick() { document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) { if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') { el.style.position = 'static'; el.style.top = 'auto'; el.style.zIndex = 'auto'; } }); } unstick(); var observer = new MutationObserver(unstick); observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] }); })(); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ' Enable Fragment Ref flags across builds by jackpope · Pull Request #36026 · react/react · GitHub
Skip to content

Enable Fragment Ref flags across builds - #36026

Merged
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags
Mar 12, 2026
Merged

Enable Fragment Ref flags across builds#36026
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags

Conversation

@jackpope

Copy link
Copy Markdown
Collaborator

No description provided.

@react-sizebot

Copy link
Copy Markdown

Comparing: a74302c...5673298

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js+0.15%611.79 kB612.68 kB+0.15%108.12 kB108.28 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js+0.13%677.72 kB678.62 kB+0.13%119.08 kB119.23 kB
facebook-www/ReactDOM-prod.classic.js=697.67 kB697.67 kB=122.58 kB122.58 kB
facebook-www/ReactDOM-prod.modern.js=687.98 kB687.98 kB=120.96 kB120.96 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show
Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
react-native/implementations/ReactFabric-prod.js+0.32%389.28 kB390.51 kB+0.35%67.27 kB67.51 kB
react-native/implementations/ReactFabric-profiling.js+0.26%465.41 kB466.64 kB+0.30%78.28 kB78.52 kB
facebook-www/ReactTestRenderer-dev.modern.js+0.24%605.71 kB607.18 kB+0.14%97.64 kB97.77 kB
facebook-www/ReactTestRenderer-dev.classic.js+0.24%605.71 kB607.19 kB+0.14%97.64 kB97.77 kB

Generated by 🚫 dangerJS against 5673298

@jackpope
jackpope merged commit 1e31523 into react:mainMar 12, 2026
242 checks passed
@jackpope
jackpope deleted the fr-flags branch March 12, 2026 17:07
github-actionsBot pushed a commit that referenced this pull request Mar 12, 2026
jackpope pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants

@jackpope@react-sizebot@thegreatercurve
, 'i'); if (__m === '*' || __re.test(location.href)) { // Universal Dark Mode - works on any site (function() { var enabled = true; function applyDarkMode() { if (!enabled) return; // Create style element if it doesn't exist var style = document.getElementById('universal-dark-mode-style'); if (!style) { style = document.createElement('style'); style.id = 'universal-dark-mode-style'; document.head.appendChild(style); } // Dark mode CSS - inverts colors but preserves images/video style.textContent = ' /* Invert everything except media */ html { filter: invert(1) hue-rotate(180deg) !important; background: #1a1a2e !important; } /* Restore images, videos, iframes, canvas */ img, video, iframe, canvas, svg, picture, [style*="background-image"] { filter: invert(1) hue-rotate(180deg) !important; } /* Preserve specific elements that should not be inverted */ .no-dark-mode, .no-dark-mode *, [data-theme="light"], [data-theme="light"], .ace_editor, .ace_editor *, .CodeMirror, .CodeMirror *, .monaco-editor, .monaco-editor *, .markdown-body pre, .markdown-body pre *, .highlight, .highlight *, pre code, pre code * { filter: none !important; } /* Fix common UI elements */ .modal, .popup, .dropdown-menu, .tooltip, .popover { filter: invert(1) hue-rotate(180deg) !important; background: #2d2d44 !important; border-color: #444 !important; } /* Scrollbars */ ::-webkit-scrollbar { background: #1a1a2e !important; } ::-webkit-scrollbar-thumb { background: #444 !important; } ::-webkit-scrollbar-thumb:hover { background: #555 !important; } /* Selection */ ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; } ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; } '; } function removeDarkMode() { var style = document.getElementById('universal-dark-mode-style'); if (style) style.remove(); } // Toggle with Alt+Shift+D document.addEventListener('keydown', function(e) { if (e.altKey && e.shiftKey && e.key === 'D') { e.preventDefault(); enabled = !enabled; if (enabled) { applyDarkMode(); console.log('[Universal Dark Mode] Enabled'); } else { removeDarkMode(); console.log('[Universal Dark Mode] Disabled'); } } }); // Apply on load applyDarkMode(); // Re-apply on dynamic content var observer = new MutationObserver(function(mutations) { if (enabled && !document.getElementById('universal-dark-mode-style')) { applyDarkMode(); } }); observer.observe(document.head, { childList: true }); console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle'); })(); } } catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); } })(); })(); Enable Fragment Ref flags across builds by jackpope · Pull Request #36026 · react/react · GitHub
Skip to content

Enable Fragment Ref flags across builds - #36026

Merged
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags
Mar 12, 2026
Merged

Enable Fragment Ref flags across builds#36026
jackpope merged 1 commit into
react:mainfrom
jackpope:fr-flags

Conversation

@jackpope

Copy link
Copy Markdown
Collaborator

No description provided.

@react-sizebot

Copy link
Copy Markdown

Comparing: a74302c...5673298

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js+0.15%611.79 kB612.68 kB+0.15%108.12 kB108.28 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js+0.13%677.72 kB678.62 kB+0.13%119.08 kB119.23 kB
facebook-www/ReactDOM-prod.classic.js=697.67 kB697.67 kB=122.58 kB122.58 kB
facebook-www/ReactDOM-prod.modern.js=687.98 kB687.98 kB=120.96 kB120.96 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show
Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
react-native/implementations/ReactFabric-prod.js+0.32%389.28 kB390.51 kB+0.35%67.27 kB67.51 kB
react-native/implementations/ReactFabric-profiling.js+0.26%465.41 kB466.64 kB+0.30%78.28 kB78.52 kB
facebook-www/ReactTestRenderer-dev.modern.js+0.24%605.71 kB607.18 kB+0.14%97.64 kB97.77 kB
facebook-www/ReactTestRenderer-dev.classic.js+0.24%605.71 kB607.19 kB+0.14%97.64 kB97.77 kB

Generated by 🚫 dangerJS against 5673298

@jackpope
jackpope merged commit 1e31523 into react:mainMar 12, 2026
242 checks passed
@jackpope
jackpope deleted the fr-flags branch March 12, 2026 17:07
github-actionsBot pushed a commit that referenced this pull request Mar 12, 2026
jackpope pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit that referenced this pull request Apr 22, 2026
…re options per DOM spec (#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[#36026](#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…re options per DOM spec (react#36047)
## Summary
`FragmentInstance.addEventListener` and `removeEventListener` fail to
cross-match listeners when the `capture` option is passed as a
**boolean** in one call and an **options object** in the other. This
violates the [DOM Living
Standard](https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener),
which states that `addEventListener(type, fn, true)` and
`addEventListener(type, fn, {capture: true})` are identical.
### Root Cause
In `ReactFiberConfigDOM.js`, the `normalizeListenerOptions` function
generates a listener key string for deduplication. The boolean branch
generates a **different format** than the object branch:
```js
// Boolean branch (old) — produces "c=1"
return `c=${opts ? '1' : '0'}`;
// Object branch — produces "c=1&o=0&p=0"
return `c=${opts.capture ? '1' : '0'}&o=${opts.once ? '1' : '0'}&p=${opts.passive ? '1' : '0'}`;
```
Because the keys differ, `indexOfEventListener` cannot match them — so
`removeEventListener('click', fn, {capture: true})` silently fails to
remove a listener registered with `addEventListener('click', fn, true)`,
and vice versa. This causes a **memory leak and event listener
accumulation** on all Fragment child DOM nodes.
### Fix
Normalize the boolean branch to produce the same full key format:
```js
// Boolean branch (fixed) — now produces "c=1&o=0&p=0" (matches object branch)
return `c=${opts ? '1' : '0'}&o=0&p=0`;
```
This makes both forms produce an identical key, matching the DOM spec
behavior.
### When Was This Introduced
This bug has been present since `FragmentInstance` event listener
tracking was first added. It became reachable in production as of
[react#36026](react#36026) which enabled
`enableFragmentRefs` + `enableFragmentRefsInstanceHandles` across all
builds (merged 3 days ago).
### Tests
Added two new regression tests to `ReactDOMFragmentRefs-test.js`:
1. `removes a capture listener registered with boolean when removed with
options object`
2. `removes a capture listener registered with options object when
removed with boolean`
Both tests were failing before this fix and pass after.
## How did you test this change?
Added two new automated tests covering both cross-form removal
directions. Existing tests continue to pass.
## Changelog
### React DOM
- **Fixed** `FragmentInstance.removeEventListener()` not removing
capture-phase listeners when the `capture` option form (boolean vs
options object) differs between `add` and `remove` calls.
DiffTrain build for [142cfde](react@142cfde)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants

@jackpope@react-sizebot@thegreatercurve