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• [feat] Update eslint rules for better a11y support #13412
• [feat] Update AGENTS rules for better a11y practices #13411
• [fix] Ensure help Tooltips are accessible #13379
• [fix] Ensure anchor links in Markdown headers are accessible from keyboard #13378 👈 (View in Graphite)
• [refactor] Centralize focus ring styling #13340
• develop

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📉 Frontend coverage change detected

The frontend unit test (vitest) coverage has decreased by 0.0000%

• Current PR: 86.3500% (12622 lines, 1722 missed)
• Latest develop: 86.3500% (12618 lines, 1722 missed)

✅ Coverage change is within normal range.

📊 View detailed coverage comparison

📉 Python coverage change detected

The Python unit test coverage has decreased by 0.0048%

• Current PR: 92.7910% (20960 statements, 1511 missed)
• Latest develop: 92.7958% (20960 statements, 1510 missed)

✅ Coverage change is within normal range.

📊 View detailed coverage comparison

Summary

This PR improves keyboard accessibility for Markdown/Heading anchor links and related tooltip behavior by making anchor icons keyboard focusable/visible on focus, stabilizing heading accessible names via aria-labelledby, adding focus styles for markdown links, and introducing a Playwright helper (tab_until_focused) to reduce e2e flakiness.

Code Quality

• Good patterns: The aria-label on the anchor icon and aria-hidden on the SVG are solid accessibility improvements (frontend/lib/src/components/shared/StreamlitMarkdown/StreamlitMarkdown.tsx L254-L266). The aria-labelledby approach to prevent action icons from polluting the heading’s accessible name is well explained and scoped to only cases where action elements exist (StreamlitMarkdown.tsx L317-L355).
• Potential a11y regression: The Escape handling for focus-triggered tooltips blurs the active element (frontend/lib/src/components/shared/Tooltip/Tooltip.tsx L141-L164). This closes the tooltip, but it also removes focus from the trigger, which can break keyboard flow (next Tab often restarts from the top of the document). See recommendation Implement Caching object to support running code blocks only once #1.
• Link focus styling fallback: In markdown styles, a:focus removes the outline, while the visible ring is only applied to :focus-visible (frontend/lib/src/components/shared/StreamlitMarkdown/styled-components.ts L42-L52). If :focus-visible isn’t supported (or behaves inconsistently), focused links may become effectively invisible. See recommendation Improve caching code #2.

Test Coverage

• Frontend unit tests:
  • Added coverage for aria-labelledby behavior when help is present and when the anchor icon is present (frontend/lib/src/components/shared/StreamlitMarkdown/StreamlitMarkdown.test.tsx L426-L464).
  • Added Escape-dismiss behavior test for focus-triggered tooltips (frontend/lib/src/components/shared/Tooltip/Tooltip.test.tsx L98-L116). The test currently encodes the “blur on Escape” semantics, which is exactly the behavior I’m concerned about.
• E2E tests:
  • Added keyboard navigation coverage for heading anchor icon visibility and activation (e2e_playwright/st_heading_test.py L160-L182).
  • Added similar coverage for markdown heading anchors (e2e_playwright/st_markdown_test.py L321-L347).
  • The new tab_until_focused helper is aligned with the e2e best-practice guidance to avoid brittle “N tabs” assumptions (e2e_playwright/shared/app_utils.py L1007-L1056).

Overall: tests cover the new behaviors well, but I’d like the tooltip Escape semantics adjusted (and tests updated accordingly).

Backwards Compatibility

• No public Python API or protobuf changes.
• Frontend changes are additive (ARIA attributes, focus styles). The main behavioral change is tooltip dismissal semantics and anchor icon visibility mechanics.

Security & Risk

• No obvious security risks.
• Main regression risk is keyboard UX: blurring on Escape can cause users to lose their place in the tab order (see recommendation Implement Caching object to support running code blocks only once #1).

Recommendations

1. Fix Escape-to-dismiss tooltips without blurring the trigger.

   • Where: frontend/lib/src/components/shared/Tooltip/Tooltip.tsx L141-L164.
   • Why: Blurring removes focus from the trigger, which is typically not expected for tooltips/popovers and can disrupt keyboard navigation.
   • Suggestion: If BaseWeb supports it, prefer an explicit onEsc/onEscape handler on StatefulTooltip (similar to Popover usage in frontend/lib/src/components/widgets/DataFrame/Tooltip.tsx L82-L84). If not, consider moving StatefulTooltip into a controlled-open pattern (track isOpen and pass it into the component) so Escape can close the tooltip while keeping focus on the trigger.
   • Follow-up: Update frontend/lib/src/components/shared/Tooltip/Tooltip.test.tsx L98-L116 to assert the tooltip closes but the trigger retains focus.

2. Avoid removing focus outline without a fallback.

   • Where: frontend/lib/src/components/shared/StreamlitMarkdown/styled-components.ts L42-L52.
   • Why: outline: none on :focus can make focus invisible in environments where :focus-visible isn’t applied.
   • Suggestion: Either remove the &:focus { outline: none } rule, or provide a visible focus style for :focus as a fallback (and then optionally refine for :focus-visible).

3. (Optional) Make tab_until_focused even more Playwright-native.

   • Where: e2e_playwright/shared/app_utils.py L1007-L1056.
   • Suggestion: Consider using expect(locator).to_be_focused() within a bounded retry/wait helper instead of evaluate(':focus') (keeps behavior closer to Playwright’s auto-waiting). This is optional—current implementation is reasonable.

Verdict

CHANGES REQUESTED: Core accessibility intent is strong, but the current Escape handling for focus-triggered tooltips removes focus from the trigger, which is likely a keyboard UX regression.

This is an automated AI review. Please verify the feedback and use your judgment.

Merge activity

• Dec 22, 5:24 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Dec 22, 5:24 PM UTC: @sfc-gh-bnisco merged this pull request with Graphite.