Specific Assist errors for domain/device class

[synesthesiam]

Breaking change

Proposed change

Use specific Assist errors for domain/device class. For example, "turn on kitchen lights" will now respond with "kitchen does not contain a light" instead of "Sorry, I couldn't understand that". Likewise, "close bedroom windows" will respond "bedroom does not contain a window".

To make this work, the ServiceIntentHandler was modified to raise a new NoStatesMatchedError, which is bubbled up by intent.async_handle to the default agent. This error must be raised inside the intent handler because it is only after filtering entities based on the constraints that we know nothing matches [1]. The error must be bubbled up because only the default agent knows how to produce the correct translated responses.

[1] Additionally, other intent handlers may not care if nothing matches. GetStateIntentHandler is one of these, which would just respond "0" to "how many lights are in the kitchen" if there are no lights instead of raising an error.

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• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
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• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

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• This PR fixes or closes issue: fixes #
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[balloob]

Suggested change

	if no_states_error.area:
	# Check device classes first, since it's more specific than domain
	if no_states_error.device_classes:
	# No exposed entities of a particular class in an area.
	# Example: "close the bedroom windows"
	error_response_type = ResponseType.NO_DEVICE_CLASS
	error_response_args["area"] = no_states_error.area
	# Only use the first device class for the error message
	error_response_args["device_class"] = next(
	iter(no_states_error.device_classes)
	)
	elif no_states_error.domains:
	# No exposed entities of a domain in an area.
	# Example: "turn on lights in kitchen"
	error_response_type = ResponseType.NO_DOMAIN
	error_response_args["area"] = no_states_error.area
	# Only use the first domain for the error message
	error_response_args["domain"] = next(iter(no_states_error.domains))
	return error_response_type, error_response_args
	if not no_states_error.area:
	return error_response_type, error_response_args
	# Check device classes first, since it's more specific than domain
	if no_states_error.device_classes:
	# No exposed entities of a particular class in an area.
	# Example: "close the bedroom windows"
	error_response_type = ResponseType.NO_DEVICE_CLASS
	error_response_args["area"] = no_states_error.area
	# Only use the first device class for the error message
	error_response_args["device_class"] = next(
	iter(no_states_error.device_classes)
	)
	return error_response_type, error_response_args
	# No exposed entities of a domain in an area.
	# Example: "turn on lights in kitchen"
	error_response_type = ResponseType.NO_DOMAIN
	error_response_args["area"] = no_states_error.area
	# Only use the first domain for the error message
	error_response_args["domain"] = next(iter(no_states_error.domains))
	return error_response_type, error_response_args

[synesthesiam]

I refactored the top guard clause to exit early if there isn't an area as well as at least one domain/device class.
Otherwise, this suggestion could fail on next(iter(no_states_error.domains))

[frenck]

I've marked this PR, as changes are requested that need to be processed.
Please un-draft it once it is ready for review again by clicking the "Ready for review" button.

Thanks! 👍

../Frenck

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