fix: support home discovery when there are no maps

[allenporter]

Allow home discovery to continue without any current homes.

Issue: home-assistant/core#159737

[Copilot]

Pull request overview

This PR updates the V1 HomeTrait discovery/refresh flow to tolerate devices that currently have no maps, so Home Assistant can complete “home discovery” without raising and aborting initialization.

Changes:

• Make HomeTrait.discover_home() no-op (cache empty data) instead of raising when there’s no current map info.
• Make HomeTrait.refresh() return early (instead of raising) when current map info isn’t available.
• Update/extend the unit test coverage for the “no maps” discovery scenario.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
roborock/devices/traits/v1/home.py	Avoid exceptions when MapsTrait has no current map info; cache empty discovery results and make refresh a safe no-op.
tests/devices/traits/v1/test_home.py	Adjust expectations for “no maps” discovery (and refresh) to ensure the trait remains stable and empty.

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[Copilot]

current_map_info is None can occur for reasons other than “no maps” (e.g., StatusTrait.current_map not refreshed / is None, or the current map flag not present in map_info). In those cases this path marks discovery as completed and persists an empty cache, which can mask a real precondition error and prevent refresh() from attempting full discovery later. Consider narrowing this branch to the explicit “no maps” case (e.g., self._maps_trait.multi_map_count == 0 and not self._maps_trait.map_info) and otherwise keep the previous failure behavior (raise) or leave _discovery_completed false and return without overwriting the cache.

Suggested change

	_LOGGER.debug("Cannot perform home discovery without current map info")
	self._discovery_completed = True
	await self._update_home_cache({}, {})
	return
	if self._maps_trait.multi_map_count == 0 and not self._maps_trait.map_info:
	_LOGGER.debug("No maps available for home discovery")
	self._discovery_completed = True
	await self._update_home_cache({}, {})
	return
	raise RoborockInvalidStatus("Cannot perform home discovery without current map info")

[allenporter]

I'm not sure this is worth changing.

[Lash-L]

I think I agree?

Our cache should be able to handle going from None to new data I believe on any errors or anything