Replace Climate HVAC_MODE_* constants with HVACMode enum

[frenck]

Breaking change

Developers only: All HVAC_MODE_* constants from the Climate platform, have been deprecated. Use the new HVACMode enum instead.

Proposed change

See above.

Type of change

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

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Replace Climate HVAC_MODE_* constants with HVACMode enum developers.home-assistant#1295

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

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• Documentation added/updated for www.home-assistant.io

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[probot-home-assistant]

Hey there @home-assistant/core, mind taking a look at this pull request as it has been labeled with an integration (demo) you are listed as a code owner for? Thanks!
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[probot-home-assistant]

Hey there @home-assistant/core, mind taking a look at this pull request as it has been labeled with an integration (climate) you are listed as a code owner for? Thanks!
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[bdraco]

Looks like there are quite a few that expect None aka STATE_UNKNOWN is a valid state.

I can think of two solutions that don't involve changing all the legacy right now:

--- a/homeassistant/components/climate/__init__.py
+++ b/homeassistant/components/climate/__init__.py
@@ -211,8 +211,10 @@ class ClimateEntity(Entity):
 
     @final
     @property
-    def state(self) -> str:
+    def state(self) -> str | None:
         """Return the current state."""
+        if self.hvac_mode is None:
+            return None
         if not isinstance(self.hvac_mode, HVACMode):
             return HVACMode(self.hvac_mode).value
         return self.hvac_mode.value

--- a/homeassistant/components/climate/__init__.py
+++ b/homeassistant/components/climate/__init__.py
@@ -9,6 +9,7 @@ from typing import Any, final
 
 import voluptuous as vol
 
+from homeassistant.helpers.frame import report
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
     ATTR_TEMPERATURE,
@@ -208,11 +209,20 @@ class ClimateEntity(Entity):
     _attr_target_temperature_step: float | None = None
     _attr_target_temperature: float | None = None
     _attr_temperature_unit: str
+    _reported_invalid_state = False
 
     @final
     @property
-    def state(self) -> str:
+    def state(self) -> str | None:
         """Return the current state."""
+        if self.hvac_mode is None:
+            if not self._reported_invalid_state:
+                self._reported_invalid_state = True
+                report(
+                    "Provided an HVACMode of 'None'; This will raise a ValueError exception in 2022.10 and later.",
+                    exclude_integrations={"climate"},
+                )
+            return None
         if not isinstance(self.hvac_mode, HVACMode):
             return HVACMode(self.hvac_mode).value
         return self.hvac_mode.value

[bdraco]

The changes look good 👍

Resolving the None case seems like the sticking point here.

[MartinHjelmare]

I think we should allow returning None to represent unknown state. It makes it consistent with almost all other entities.

[frenck]

I think we should allow returning None to represent unknown state. It makes it consistent with almost all other entities.

Agreed. Will adjust to that.

[MartinHjelmare]

Does the frontend handle unknown state ok in the climate card?

[frenck]

Does the frontend handle unknown state ok in the climate card?

It does that perfectly actually, when the state becomes None (unknown) the UI disables the card:

[bdraco]

Nice!