perf(Dialog): use stable context value reference

[hectahertz]

Closes #

DialogContext.Provider was receiving value={{}} which creates a new object reference on every render. Since this context is only used as a presence check (useContext(DialogContext) !== undefined), a module-level constant works perfectly.

Changelog

New

N/A

Changed

• Hoisted DialogContext value to a module-level constant to avoid new object allocation on every render

Removed

N/A

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

Trivial change, no behavioral difference. The context value is only used as a presence check.

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

[changeset-bot]

🦋 Changeset detected

Latest commit: daee366

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	Patch

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]

⚠️ 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. Or, apply the integration-tests: skipped manually label to skip these checks.

[Copilot]

Pull request overview

This PR optimizes @primer/react’s Dialog by avoiding a new DialogContext.Provider value object allocation on every render, since the context is used only as a presence sentinel.

Changes:

• Hoists the DialogContext provider value into a module-level constant for a stable reference.
• Adds a patch changeset documenting the performance optimization.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
packages/react/src/Dialog/Dialog.tsx	Uses a module-level constant for DialogContext.Provider value instead of an inline {} per render.
.changeset/perf-dialog-stable-context.md	Patch changeset describing the stable context value optimization.

[Copilot]

DIALOG_CONTEXT_VALUE is a shared mutable object across all Dialog instances. If any consumer ever mutates the context value (even accidentally), that mutation will persist across renders and leak between dialogs. To keep the “presence check only” invariant and avoid mutation-related footguns, use an immutable sentinel (e.g. Object.freeze({}) as done in deprecated/utils/create-slots.tsx).

Suggested change

	const DIALOG_CONTEXT_VALUE = {}
	const DIALOG_CONTEXT_VALUE = Object.freeze({})

[Copilot]

PR metadata indicates tests were “Added/updated”, but this PR only changes the Dialog context value and adds a changeset (no test updates). Please either update the checklist/description to reflect reality, or add coverage that would fail if the context value regressed to an unstable reference.