[seaspotter]

Follow-up zu #3895 (siehe Review-Kommentar von Copilot).

Problem

Die neue Verbindungssperre in ModbusClient schuetzt nur Aufrufe ueber die eigenen Wrapper-Methoden. Drei Stellen greifen direkt auf self._delegate/.delegate zu und umgehen die Sperre damit vollstaendig:

• sungrow_sh/bat.py:83 - liest ein rohes Register fuer ein Bitfeld
• marstek/venus_c_e/bat.py:38 - braucht FC06, write_register() nutzt intern FC16
• openwb_series2_satellit/chargepoint_module.py (Phasenumschaltung) - selbes FC06-Problem, genau auf der Verbindung, fuer die die Sperre urspruenglich gedacht war

Fix

• Sungrow: Umstellung auf den normalen, gesperrten Lesepfad (ModbusDataType.UINT_16 liefert denselben Rohwert fuers Bitmasking)
• Neue Methode ModbusClient.write_single_register_raw() fuer echtes FC06, gesperrt - Marstek und die Phasenumschaltung nutzen sie jetzt statt des rohen Delegates

[Copilot]

🔵 Needs a closer look

is_socket_open() still accesses the delegate without acquiring the shared lock.

Pull request overview

This follow-up secures remaining Modbus delegate accesses, adds locked FC06 writes, and expands retry coverage.

Changes:

• Routes Sungrow reads through the locked wrapper.
• Adds locked single-register writes for Marstek and phase switching.
• Broadens retry handling and adds regression tests.

File summaries

File	Summary
packages/modules/devices/sungrow/sungrow_sh/bat.py	Uses the locked register-read path.
packages/modules/devices/marstek/venus_c_e/bat.py	Uses locked FC06 writes.
packages/modules/common/modbus.py	Adds locking and raw single-register writes.
packages/modules/common/modbus_test.py	Tests serialization and FC06 behavior.
packages/modules/common/hardware_check.py	Retries broader exception types.
packages/modules/common/hardware_check_test.py	Tests retry behavior.
packages/modules/chargepoints/openwb_series2_satellit/chargepoint_module.py	Uses locked phase-switch writes.

Review details

Suppressed comments (1)

packages/modules/common/modbus.py:107

• is_socket_open() still calls _delegate.is_socket_open() without acquiring _lock (line 97). The internal calls here are protected by the surrounding RLock, but the public method remains an unlocked delegate access, so a concurrent socket check can race with connect() or close() and violate the serialization this change introduces. Guard is_socket_open() with the same lock; the RLock keeps these nested calls safe.

        with self._lock:
            if self.is_socket_open() is False:
                self.connect()

• Files reviewed: 7/7 changed files
• Comments generated: 0
• Review effort level: Lite

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