home-assistant-modernization-standards

name	Home Assistant Modernization Standards
description	Guidelines for adhering to modern Home Assistant lifecycle and component structure rules (like runtime_data).

Home Assistant Modernization Standards

This skill ensures that all changes and additions to this integration align with modern Home Assistant development practices, lifecycle methods, and architecture requirements.

Guidelines

1. Replaces hass.data with ConfigEntry.runtime_data

• For Home Assistant core version compatibility, always store active runtime data (like the coordinator instance) using the typed ConfigEntry.runtime_data pattern instead of storing objects globally in hass.data[DOMAIN].

2. Async Lifecycle & Config Entry Setup

• During config entry setup (async_setup_entry), ensure any network-dependent actions (like connecting to the api/device) are managed cleanly.
• Do not perform blocking, synchronous updates directly during setup. Leverage DataUpdateCoordinator and handle first-refresh behavior carefully to avoid triggering Home Assistant's configuration entry setup timeouts (CancelledError).

3. Graceful Property Access

• All sensor and binary_sensor entities should handle situations where the coordinator has no data (self.coordinator.data is None) gracefully. Return appropriate defaults (e.g. None or 0) rather than raising a TypeError or AttributeError.