remove primer_react_breadcrumbs_overflow_menu feature flag

[liuliu-dev]

https://github.com/github/feature-flag-lifecycle/issues/8423

Changelog

New

Changed

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

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-ui (Learn more about how to run integration tests)

[changeset-bot]

🦋 Changeset detected

Latest commit: 984e6e6

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

This PR includes changesets to release 1 package

Name	Type
@primer/react	Minor

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[github-actions]

⚠️ Action required

👋 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. Check the integration testing docs for step-by-step instructions. Or, apply the integration-tests: skipped manually label to skip these checks.

To publish a canary release for integration testing, apply the Canary Release label to this PR.

[primer]

🤖 Lint issues have been automatically fixed and committed to this PR.

[primer-integration]

👋 Hi from github/github-ui! Your integration PR is ready: https://github.com/github/github-ui/pull/18531

[primer-integration]

Integration test results from github/github-ui:

  CI Passed
  VRT Passed
  Projects Passed

All checks passed!

[Copilot]

Pull request overview

This PR removes the primer_react_breadcrumbs_overflow_menu feature flag and makes the Breadcrumbs overflow menu behavior permanently enabled, aligning the component’s behavior with the graduated feature.

Changes:

• Removed primer_react_breadcrumbs_overflow_menu from default feature flags and eliminated useFeatureFlag gating in Breadcrumbs.
• Updated Breadcrumbs tests and Storybook feature stories to no longer enable the removed flag explicitly.
• Added a changeset for a minor release documenting the graduation.

Show a summary per file

File	Description
packages/react/src/FeatureFlags/DefaultFeatureFlags.ts	Removes the breadcrumbs overflow menu flag from the default flag set.
packages/react/src/Breadcrumbs/Breadcrumbs.tsx	Removes feature-flag gating so overflow menu logic is always active.
packages/react/src/Breadcrumbs/tests/Breadcrumbs.test.tsx	Drops explicit flag enabling in tests (some test descriptions still reference the flag).
packages/react/src/Breadcrumbs/Breadcrumbs.features.stories.tsx	Removes FeatureFlags wrapper and updates stories to reflect always-on overflow menu behavior.
.changeset/graduate-breadcrumbs-overflow-menu.md	Documents the feature flag graduation as a minor release.

Copilot's findings

Comments suppressed due to low confidence (2)

packages/react/src/Breadcrumbs/tests/Breadcrumbs.test.tsx:523

• The surrounding test suite (describe('variant prop (feature flag on)') above this block) still references the removed feature flag. Rename the describe title to reflect the always-on behavior.

            Docs
          </Breadcrumbs.Item>
        </Breadcrumbs>,
      )
      expect(container.firstChild).toHaveAttribute('data-variant', 'normal')
    })

packages/react/src/Breadcrumbs/Breadcrumbs.tsx:253

• handleResize only updates state when both visibleItems.length and menuItems.length change (&&). If the set of children changes but the overflow split sizes don’t both change, the component can keep stale visibleItems/menuItems and render the wrong crumbs. Consider updating when either length changes (or when the arrays differ), or resetting overflow state when childArray changes.

        if (
          (visibleItems.length !== result.visibleItems.length && menuItems.length !== result.menuItems.length) ||
          result.effectiveHideRoot !== effectiveHideRoot
        ) {

• Files reviewed: 5/5 changed files
• Comments generated: 2

[Copilot]

The comment says the root item should be included inside the overflow menu when it’s visible, but the code slices it out (menuItems.slice(1)) when !effectiveHideRoot. Either update the comment to match the behavior, or adjust the logic if the root is intended to appear in the menu as well.

Suggested change

	// In 'menu-with-root' mode, include the root item inside the menu even if it's visible in the breadcrumbs
	// When the root item remains visible in the breadcrumbs, exclude it from the overflow menu to avoid duplication.

[Copilot]

This test description still references the removed feature flag (“with feature flag”). Update the test name to reflect the current behavior (overflow menu is no longer gated).

This issue also appears on line 518 of the same file.

See below for a potential fix:

  it('sets data-overflow attribute when overflow is menu', () => {