Release tracking 38.12.0

[primer]

This PR was opened by the Changesets release GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated.

Releases

@primer/react@38.12.0

Minor Changes

• #7348 3c160b2 Thanks @mattcosta7! - Add currentWidth and onResizeEnd props to PageLayout.Pane for controlled resizable width

  The PageLayout.Pane component now supports controlled width:

  • onResizeEnd — callback fired when a resize operation ends (pointer release or keyboard key up). Replaces localStorage persistence. Requires currentWidth.
  • currentWidth — sets the current displayed width in pixels (number | undefined). Pass undefined when the persisted value hasn't loaded yet. Requires onResizeEnd.

  Both props must be provided together (enforced by TypeScript). resizable remains a plain boolean prop.

  These props are only meaningful when resizable={true} — without it, no drag handle renders so onResizeEnd never fires.

  New export:

  • defaultPaneWidth — Record of preset width values: {small: 256, medium: 296, large: 320}

  Example usage:

  import {PageLayout, defaultPaneWidth} from '@primer/react'
  
  // Default behavior (unchanged) — localStorage persistence
  <PageLayout.Pane resizable />
  
  // Controlled width with custom persistence
  const [width, setWidth] = useState(defaultPaneWidth.medium)
  <PageLayout.Pane
    resizable
    currentWidth={width}
    onResizeEnd={(newWidth) => {
      setWidth(newWidth)
      myStorage.save('pane-width', newWidth)
    }}
  />
  
  // Async load — pass undefined until value is fetched
  <PageLayout.Pane
    resizable
    currentWidth={savedWidth ?? undefined}
    onResizeEnd={handleResizeEnd}
  />

Patch Changes

• #7527 c87db98 Thanks @llastflowers! - Update PageHeader story to have semantic headings

• #7535 d86c970 Thanks @francinelucca! - fix: ActionBar overflow menu not closing on select

@primer/mcp@0.2.0

Minor Changes

• #7495 b69325f Thanks @adierkens! - Adds support for fetching docs via the /llms.txt endpoint per-component

Patch Changes

• Updated dependencies [3c160b2, c87db98, d86c970]:
  • @primer/react@38.12.0

[github-actions]

❗ Pre-merge checklist

Please ensure these items are checked before merging:

🔎 Smoke test

• All CI checks pass on this pull request
• Docs and Storybook open in a browser

🌏 Integration tests

• Successful integration test with github/github-ui as a primary consumer of primer/react (automated pull request)
  • Verify all CI checks have passed on automated pull request
  • Manually test critical paths in preview
  • Manually test release-specific bugfixes and/or feature work as described in preview

✅ Peer Review

• Create release review issue for Issues team (example)
• Wait for approval from Issues team before merging

🤔 Sanity test

• All bugfixes in this release have resolved their corresponding issues
• The issues for any reverted PRs have been re-opened and commented on with a link to the reverted PR
• No noticeable regressions have been introduced as a result of changes in this release
• Release notes accurately describe the changes made

❗ Post-merge checklist

Please ensure these items are checked after merging:

🚢 Version upgrade, cleanup, and documentation

• Upgrade @primer/react version at github/github-ui
• Close Integration test PR and delete branch
• Leave a /short-report comment on quarterly release conductor tracking issue summarizing time spent on release activities and any challenges encountered
• Leave any testing notes on the automated per-shift release tracking issue. In particular, describe any issues encountered during your testing. This is helpful in providing historical context to the next release conductor as well as other maintainers.

[github-actions]

👋 Hi, this pull request contains changes to the source code that github/github-ui depends on. If you are GitHub staff, test these changes with github/github-ui using the integration workflow. Or, apply the integration-tests: skipped manually label to skip these checks.

[llastflowers]

confirmed integration tests passed, but are just not updating here