Fixes issue with Tooltip description id overriding existing description ids

[owenniblock]

Relates to https://github.com/github/accessibility-audits/issues/10890

Blocks rollout of this PR: https://github.com/github/github/pull/383309

Changelog

N/A

New

Changed

The TooltipV2 no longer clears the existing aria-describedby property when using description type.

Removed

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why

Testing & Reviewing

It seems like the test I added isn't run using npm run test - I think because it's in the Ignore Modules list. I managed to run it with the following command:

npx vitest run "TooltipV2"

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[changeset-bot]

🦋 Changeset detected

Latest commit: 02ede7d

The changes in this PR will be included in the next version bump.

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

👋 Hi, this pull request contains changes to the source code that github/github depends on. If you are GitHub staff, we recommend testing these changes with github/github using the integration workflow. Thanks!

[Copilot]

Pull Request Overview

This PR ensures that when using the Tooltip in description mode, any existing aria-describedby values on the trigger are preserved and the tooltip’s ID is appended, rather than replaced.

• Append tooltip ID to existing aria-describedby instead of overriding it
• Add a unit test and a story to validate the merged description behavior
• Update the changelog with a patch release entry

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
packages/react/src/TooltipV2/tests/Tooltip.test.tsx	Added test component and case for existing aria-describedby
packages/react/src/TooltipV2/Tooltip.tsx	Changed aria-describedby logic to append tooltip ID
packages/react/src/TooltipV2/Tooltip.features.stories.tsx	Added a feature story demonstrating external description usage
.changeset/two-aliens-wait.md	Documented patch release for this change

[github-actions]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	92.21 KB (-0.06% 🔽)
packages/react/dist/browser.umd.js	92.25 KB (+0.02% 🔺)