docs(toast): accessibility migration analysis

[nikkimk]

Description

In CONTRIBUTOR-DOCS/03_project-planning/03_components/toast/accessibility-migration-analysis.md:

• Documented recommendations for ARIA roles, states, and properties for the 2nd-gen Toast
• Shadow DOM and cross-root ARIA considerations documented, including why no cross-root ARIA issues exist for this component
• Accessibility tree expectations documented for all configurations: closed state, text-only, icon + text, and with action button
• Keyboard interaction model fully specified, covering focus management, Tab order through close and action buttons, and focus-return behavior on dismiss
• Testing requirements defined, including unit tests, aXe/Storybook checks, Playwright ARIA snapshots, and manual screen reader testing guidance for live region announcements
• Known 1st-gen accessibility issues cataloged with dispositions (fix in 2nd-gen): assertive live region role, missing hover pause, missing aria-hidden when closed, and action-button-plus-auto-dismiss hazard
• WCAG 4.1.3 (Status Messages) identified as the primary applicable criterion; role="status" prescribed as the fixed host role (change from 1st-gen's inner role="alert")
• 1st-gen component analysis completed, covering current ARIA implementation (role="alert" on inner .body div), timeout handling, focus-pause behavior, and existing test coverage

Motivation and context

The 2nd-gen migration is an opportunity to address known accessibility gaps, align with the latest WAI-ARIA Authoring Practices, and ensure the component meets WCAG 2.2 AA compliance.

Related issue(s)

• resolves SWC-2256

Screenshots (if appropriate)

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Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed the Accessibility Practices for this feature, see: Aria Practices
• I have added automated tests to cover my changes. (docs-only PR; no code changes)
• I have included a well-written changeset if my change needs to be published. (docs-only PR; no package changes)
• I have included updated documentation if my change required it.

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Reviewer's checklist

• Includes a Github Issue with appropriate flag or Jira ticket number without a link
• Includes thoughtfully written changeset if changes suggested include patch, minor, or major features
• Automated tests cover all use cases and follow best practices for writing
• Validated on all supported browsers
• All VRTs are approved before the author can update Golden Hash

Manual review test cases

Review the Toast accessibility migration analysis

• ARIA roles, states, and properties covered
• Shadow DOM and cross-root ARIA considerations covered
• Accessibility tree documented
• Keyboard interaction fully specified
• Testing requirements defined
• Known 1st-gen issues cataloged with dispositions
• Review the changes that include the adaptive dual-border guidance

[changeset-bot]

⚠️ No Changeset found

Latest commit: 5efd6e7

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[coveralls]

Coverage Report for CI Build 28254101860

Coverage remained the same at 96.246%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	39173
Covered Lines:	37902
Line Coverage:	96.76%
Relevant Branches:	6460
Covered Branches:	6018
Branch Coverage:	93.16%
Branches in Coverage %:	Yes
Coverage Strength:	458.82 hits per line

---

💛 - Coveralls

[github-actions]

📚 Branch Preview Links

• Documentation Site (first-gen)
• Storybook (first-gen)
• Storybook (second-gen)

🔍 First Generation Visual Regression Test Results

When a visual regression test fails (or has previously failed while working on this branch), its results can be found in the following URLs:

• Spectrum | Light | Medium | LTR
• Spectrum | Dark | Large | RTL
• Express | Light | Medium | LTR
• Express | Dark | Large | RTL
• Spectrum-two | Light | Medium | LTR
• Spectrum-two | Dark | Large | RTL
• High Contrast Mode | Medium | LTR

Deployed to Azure Blob Storage: pr-6442

If the changes are expected, update the current_golden_images_cache hash in the circleci config to accept the new images. Instructions are included in that file.
If the changes are unexpected, you can investigate the cause of the differences and update the code accordingly.

[cdransf]

Looks great! Left one tiny suggestion. ✨

[cdransf]

Suggested change

None

[5t3ph]

Blocking to discuss following React's lead with a "Toast Container" format vs. just the individual Toast component.

[5t3ph]

Unfortunately, I don't think it's realistic to say Toasts can't contain actions (and design expects them to handle actions). However, it's limited to one action.

See this thread which Michael Jordan weighed in on, although it would partly require we provide a toast container like React does. Maybe something to bring to sync on whether we should own full Toast display/positioning or just provide the base component? One thing the container offers is the ability to better handle the live announcements, which may get muddled if each Toast independently manages it. Plus ability to manage focus within the group and on dismiss.