Which design decision about controlled versus uncontrolled patterns remains inconsistent in react-bootstrap component APIs?

Answer to the Core Question

The most problematic divergence in react‑bootstrap’s API is found in Accordion, Carousel, Dropdown, and the form controls (Form.Control, Form.Select, etc.). These components expose both controlled props (e.g., activeKey, activeIndex, show, value) and uncontrolled defaults (defaultKey, defaultIndex, defaultShow, defaultValue), yet the documentation does not consistently recommend one pattern over the other.

Why This Matters

• Mixed APIs can lead to subtle bugs when a component is partially controlled (e.g., passing activeKey without handling onSelect).
• Legacy code may rely on the default internal state, making upgrades harder to maintain.
• Predictable state management across the library is harder to achieve when some components mandate controlled props while others rely on internal state.

Confirmed Facts

Component	Controlled Prop	Uncontrolled Alternative	Documentation Stance
Accordion	activeKey	defaultActiveKey	Both supported, no clear recommendation
Carousel	activeIndex	defaultActiveIndex	Both supported, docs favor controlled
Dropdown	show + onToggle	defaultShow	Inconsistent wording, controlled preferred for explicit visibility
Form controls	value + onChange	defaultValue / defaultChecked	Docs mention both, but controlled pattern is recommended for predictable validation
Modal	show (required)	None – no uncontrolled mode	Controlled only; internal focus/scroll lock handled automatically

Practical Guidance for Consistency

1. Choose a single pattern per component family. For components that expose a show, activeKey, or activeIndex prop, use the controlled approach and lift state to the parent.
2. Avoid mixing default* and controlled props. If you pass a controlled prop, do not also provide its default* counterpart; otherwise the internal state may override your intent.
3. Handle the corresponding event. For example, with activeKey you must also provide onSelect to update the parent state, otherwise the component will appear frozen.
4. Use the same pattern across the UI. If you control a Dropdown in one place, keep that pattern for all dropdowns in the same feature set to avoid confusion.
5. Upgrade to the latest major release. Minor releases often deprecate default* props in favor of fully controlled patterns. Check the changelog for each component before refactoring.

Follow‑Up Diagnostic Question

To tailor the recommendation more precisely, could you confirm which major version of react‑bootstrap you are using (e.g., 2.x or 1.x)? The controlled/uncontrolled balance shifted in the 2.x series, and the guidance above assumes the current stable release.