Keep Sofar diagnostics downloadable when the inverter is unreachable (#183218)

homeassistant/components/sofar/diagnostics.py

@@ -3,6 +3,8 @@
 from dataclasses import asdict
 from typing import Any
 
+from modbus_connection import ModbusError
+
 from homeassistant.components.diagnostics import async_redact_data
 from homeassistant.core import HomeAssistant
 
@@ -19,8 +21,13 @@ async def async_get_config_entry_diagnostics(
     """Return diagnostics for a config entry."""
     runtime_data = entry.runtime_data
     device = runtime_data.readings.device
-    raw = await device.async_read_raw()
-    if (holding := raw.get("holding")) is not None:
+    raw = masks = read_error = None
+    try:
+        raw = await device.async_read_raw()
+        masks = await device.async_read_masks()
+    except ModbusError as err:
+        read_error = type(err).__name__
+    if raw is not None and (holding := raw.get("holding")) is not None:
         for address in _SERIAL_NUMBER_REGISTERS:
             holding.pop(address, None)
 
@@ -32,11 +39,12 @@ async def async_get_config_entry_diagnostics(
             "readings_components": device.readings_components,
             "settings_components": device.settings_components,
             "active_faults": sorted(fault.key for fault in device.state.active_faults),
-            "address_masks": await device.async_read_masks(),
+            "address_masks": masks,
             "link": {
                 "tuning": asdict(runtime_data.tuner.tuning),
                 "stats": asdict(runtime_data.link.stats),
             },
+            "read_error": read_error,
             "raw": raw,
         },
         TO_REDACT,

tests/components/sofar/snapshots/test_diagnostics.ambr

@@ -194,6 +194,7 @@
         '4358': 0,
       }),
     }),
+    'read_error': None,
     'readings_components': list([
       'state',
       'grid',

tests/components/sofar/test_diagnostics.py

@@ -2,7 +2,9 @@
 
 from unittest.mock import patch
 
+from modbus_connection import ModbusConnectionError, ModbusError, ModbusTimeoutError
 from modbus_connection.mock import MockModbusConnection
+import pytest
 from syrupy.assertion import SnapshotAssertion
 from syrupy.matchers import path_type
 
@@ -83,3 +85,33 @@ async def test_diagnostics_decodes_address_masks(
     diag = await get_diagnostics_for_config_entry(hass, hass_client, init_integration)
 
     assert diag["address_masks"]["1024"] == 0x0001000200030004
+
+
+@pytest.mark.parametrize(
+    ("error", "error_name"),
+    [
+        pytest.param(ModbusTimeoutError("silent"), "ModbusTimeoutError", id="timeout"),
+        pytest.param(
+            ModbusConnectionError("gone"), "ModbusConnectionError", id="link_lost"
+        ),
+    ],
+)
+async def test_diagnostics_inverter_unreachable(
+    hass: HomeAssistant,
+    hass_client: ClientSessionGenerator,
+    mock_connection: MockModbusConnection,
+    init_integration: MockConfigEntry,
+    error: ModbusError,
+    error_name: str,
+) -> None:
+    """Test diagnostics still download when the inverter stops answering."""
+    unit = mock_connection.for_unit(1)
+    unit.fail_requests(error)
+    unit.read_events.clear()
+
+    diag = await get_diagnostics_for_config_entry(hass, hass_client, init_integration)
+
+    assert diag["read_error"] == error_name
+    assert diag["raw"] is None
+    assert diag["address_masks"] is None
+    assert len(unit.read_events) == 1