Add credentialless as a recognized boolean attribute for iframes#36148
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Add credentialless as a recognized boolean attribute for iframes#36148
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## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
|
Comparing: 3cb2c42...8709472 Critical size changesIncludes critical production bundles, as well as any change greater than 2%:
Significant size changesIncludes any change greater than 0.2%: (No significant changes) |
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hoxyq
reviewed
Apr 14, 2026
| await act(() => { | ||
| root.render(<iframe credentialless={true} />); | ||
| }); | ||
| expect(container.firstChild.getAttribute('credentialless')).toBe(''); |
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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?
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@hoxyq I believe react set this to empty string when the prop is bool, see [1]
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}
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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.
vmx906
commented
Apr 20, 2026
| case 'seamless': | ||
| case 'itemScope': { | ||
| if (value && typeof value !== 'function' && typeof value !== 'symbol') { | ||
| domElement.setAttribute(key, ''); |
| await act(() => { | ||
| root.render(<iframe credentialless={true} />); | ||
| }); | ||
| expect(container.firstChild.getAttribute('credentialless')).toBe(''); |
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@hoxyq I believe react set this to empty string when the prop is bool, see [1]
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}
hoxyq
reviewed
Apr 20, 2026
Comment on lines
2852
to
2853
| case 'controls': | ||
| case 'default': |
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@vmx906 I think you need to add credentialless here as well.
Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?
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Good catch! Updated this missing path and added test
…DOMServerIntegrationAttributes-test.js
hoxyq
approved these changes
Apr 20, 2026
github-actions Bot
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Apr 20, 2026
) ## Summary The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute. Per the [Anonymous iframe spec (WICG)](https://wicg.github.io/anonymous-iframe/): > The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false. ``` partial interface HTMLIFrameElement { attribute boolean credentialless; }; ``` Changes: - ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement` - ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering - ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists ## Test plan - Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}` sets the attribute to `''` and `credentialless={false}` removes it - All tests pass in source and www channels (590 tests each) - Flow type checking passes (dom-node renderer) - Prettier and lint pass DiffTrain build for [306a01b](306a01b)
github-actions Bot
pushed a commit
that referenced
this pull request
Apr 20, 2026
) ## Summary The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute. Per the [Anonymous iframe spec (WICG)](https://wicg.github.io/anonymous-iframe/): > The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false. ``` partial interface HTMLIFrameElement { attribute boolean credentialless; }; ``` Changes: - ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement` - ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering - ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists ## Test plan - Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}` sets the attribute to `''` and `credentialless={false}` removes it - All tests pass in source and www channels (590 tests each) - Flow type checking passes (dom-node renderer) - Prettier and lint pass DiffTrain build for [306a01b](306a01b)
hoxyq
pushed a commit
that referenced
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Apr 21, 2026
…#36322) ## Summary Follow-up to #36148 (which added credentialless as a recognized boolean attribute for iframes). Adds credentialless to possibleStandardNames so React's dev warning can suggest the correct casing when users write it as Credentialless (or another incorrect case). Includes an SSR test asserting the "Did you mean credentialless?" warning fires. ## Test plan - yarn test ReactDOMComponent passes, including the new should warn about incorrect casing on the credentialless property (ssr) case
github-actions Bot
pushed a commit
that referenced
this pull request
Apr 21, 2026
…#36322) ## Summary Follow-up to #36148 (which added credentialless as a recognized boolean attribute for iframes). Adds credentialless to possibleStandardNames so React's dev warning can suggest the correct casing when users write it as Credentialless (or another incorrect case). Includes an SSR test asserting the "Did you mean credentialless?" warning fires. ## Test plan - yarn test ReactDOMComponent passes, including the new should warn about incorrect casing on the credentialless property (ssr) case DiffTrain build for [94643c3](94643c3)
github-actions Bot
pushed a commit
that referenced
this pull request
Apr 21, 2026
…#36322) ## Summary Follow-up to #36148 (which added credentialless as a recognized boolean attribute for iframes). Adds credentialless to possibleStandardNames so React's dev warning can suggest the correct casing when users write it as Credentialless (or another incorrect case). Includes an SSR test asserting the "Did you mean credentialless?" warning fires. ## Test plan - yarn test ReactDOMComponent passes, including the new should warn about incorrect casing on the credentialless property (ssr) case DiffTrain build for [94643c3](94643c3)
github-actions Bot
pushed a commit
to code/lib-react
that referenced
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Apr 25, 2026
…ebook#36148) ## Summary The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute. Per the [Anonymous iframe spec (WICG)](https://wicg.github.io/anonymous-iframe/): > The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false. ``` partial interface HTMLIFrameElement { attribute boolean credentialless; }; ``` Changes: - ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement` - ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering - ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists ## Test plan - Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}` sets the attribute to `''` and `credentialless={false}` removes it - All tests pass in source and www channels (590 tests each) - Flow type checking passes (dom-node renderer) - Prettier and lint pass DiffTrain build for [306a01b](facebook@306a01b)
github-actions Bot
pushed a commit
to code/lib-react
that referenced
this pull request
Apr 25, 2026
…ebook#36148) ## Summary The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute. Per the [Anonymous iframe spec (WICG)](https://wicg.github.io/anonymous-iframe/): > The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false. ``` partial interface HTMLIFrameElement { attribute boolean credentialless; }; ``` Changes: - ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement` - ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering - ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists ## Test plan - Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}` sets the attribute to `''` and `credentialless={false}` removes it - All tests pass in source and www channels (590 tests each) - Flow type checking passes (dom-node renderer) - Prettier and lint pass DiffTrain build for [306a01b](facebook@306a01b)
github-actions Bot
pushed a commit
to code/lib-react
that referenced
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Apr 26, 2026
…facebook#36322) ## Summary Follow-up to facebook#36148 (which added credentialless as a recognized boolean attribute for iframes). Adds credentialless to possibleStandardNames so React's dev warning can suggest the correct casing when users write it as Credentialless (or another incorrect case). Includes an SSR test asserting the "Did you mean credentialless?" warning fires. ## Test plan - yarn test ReactDOMComponent passes, including the new should warn about incorrect casing on the credentialless property (ssr) case DiffTrain build for [94643c3](facebook@94643c3)
github-actions Bot
pushed a commit
to code/lib-react
that referenced
this pull request
Apr 26, 2026
…facebook#36322) ## Summary Follow-up to facebook#36148 (which added credentialless as a recognized boolean attribute for iframes). Adds credentialless to possibleStandardNames so React's dev warning can suggest the correct casing when users write it as Credentialless (or another incorrect case). Includes an SSR test asserting the "Did you mean credentialless?" warning fires. ## Test plan - yarn test ReactDOMComponent passes, including the new should warn about incorrect casing on the credentialless property (ssr) case DiffTrain build for [94643c3](facebook@94643c3)
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Summary
The
credentiallessattribute is a boolean HTML attribute for<iframe>elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.Per the Anonymous iframe spec (WICG):
Changes:
setPropanddiffHydratedGenericElementpushAttributefor server-side renderingTest plan
credentialless={true}sets the attribute to''andcredentialless={false}removes it