Enforce React Refresh component-only exports

[joshblack]

Closes #

No linked issue.

Enables react-refresh/only-export-components as an error after the preceding stack layers move non-component exports out of component files.

Changelog

New

• Added react-refresh/only-export-components to the flat ESLint config.

Changed

• Configured the rule for this codebase's patterns, including constant exports, Next metadata, compound Object.assign components, and fixedForwardRef.
• Skips the styled-react TSX entrypoint barrel because the package build expects that filename and it only re-exports deprecated APIs.

Removed

• Nothing.

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; lint enforcement only, no consumer-facing runtime change.

Testing & Reviewing

Validated the configured rule reported zero remaining React Refresh violations before enabling it. Full validation passed for format, lint, CSS lint, type-check, and build; full browser test runs hit transient timeouts, and the affected files passed on targeted rerun.

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]

⚠️ No Changeset found

Latest commit: 06623dc

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

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

[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.

[Copilot]

Pull request overview

This PR tightens the repo’s linting baseline by enabling react-refresh/only-export-components as an error in the root flat ESLint config, enforcing React Fast Refresh–compatible “component-only” exports across JSX/TSX sources.

Changes:

• Added eslint-plugin-react-refresh to the ESLint flat config and enabled react-refresh/only-export-components at error severity for **/*.{jsx,tsx}.
• Tuned rule options to match repo patterns (allow constant exports, allow metadata, recognize additional HOC-style wrappers via extraHOCs).
• Exempted packages/styled-react/src/index.tsx from this rule via a targeted ignore.

Show a summary per file

File	Description
eslint.config.mjs	Adds and configures react-refresh/only-export-components for JSX/TSX files, with repo-specific allowances and a scoped ignore.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 0

[primer-integration]

Integration test results from github/github-ui PR:

  CI Passed
  VRT Passed
  Projects Passed

All checks passed!