Fix hide empty sections in mqtt subentry flows (#148692)

homeassistant/components/mqtt/config_flow.py

@@ -2114,6 +2114,9 @@ def data_schema_from_fields(
         if schema_section is None:
             data_schema.update(data_schema_element)
             continue
+        if not data_schema_element:
+            # Do not show empty sections
+            continue
         collapsed = (
             not any(
                 (default := data_schema_fields[str(option)].default) is vol.UNDEFINED

tests/components/mqtt/test_config_flow.py

@@ -3220,7 +3220,7 @@ async def test_subentry_configflow(
         "url": learn_more_url(component["platform"]),
     }
 
-    # Process entity details setep
+    # Process entity details step
     assert result["step_id"] == "entity_platform_config"
 
     # First test validators if set of test
@@ -4212,3 +4212,52 @@ async def test_subentry_reconfigure_availablity(
         "payload_available": "1",
         "payload_not_available": "0",
     }
+
+
+async def test_subentry_configflow_section_feature(
+    hass: HomeAssistant,
+    mqtt_mock_entry: MqttMockHAClientGenerator,
+) -> None:
+    """Test the subentry ConfigFlow sections are hidden when they have no configurable options."""
+    await mqtt_mock_entry()
+    config_entry = hass.config_entries.async_entries(mqtt.DOMAIN)[0]
+
+    result = await hass.config_entries.subentries.async_init(
+        (config_entry.entry_id, "device"),
+        context={"source": config_entries.SOURCE_USER},
+    )
+    assert result["type"] is FlowResultType.FORM
+    assert result["step_id"] == "device"
+    result = await hass.config_entries.subentries.async_configure(
+        result["flow_id"],
+        user_input={"name": "Bla", "mqtt_settings": {"qos": 1}},
+    )
+    assert result["type"] is FlowResultType.FORM
+
+    result = await hass.config_entries.subentries.async_configure(
+        result["flow_id"],
+        user_input={"platform": "fan"},
+    )
+    assert result["type"] is FlowResultType.FORM
+    assert result["description_placeholders"] == {
+        "mqtt_device": "Bla",
+        "platform": "fan",
+        "entity": "Bla",
+        "url": learn_more_url("fan"),
+    }
+
+    # Process entity details step
+    assert result["step_id"] == "entity_platform_config"
+
+    result = await hass.config_entries.subentries.async_configure(
+        result["flow_id"],
+        user_input={"fan_feature_speed": True},
+    )
+    assert result["type"] is FlowResultType.FORM
+    assert result["errors"] == {}
+    assert result["step_id"] == "mqtt_platform_config"
+
+    # Check mqtt platform config flow sections from data schema
+    data_schema = result["data_schema"].schema
+    assert "fan_speed_settings" in data_schema
+    assert "fan_preset_mode_settings" not in data_schema