wavinAhc9000 fails to compile on ESPHome 2026.8.2 (modbus hook signatures out of date) - Board rev. 1

[mwhallberg]

Note: This issue was drafted by an AI assistant on my behalf. I hit the compile error as an end user, so I may not be able to answer deep technical follow-up questions myself — but I'm happy to test any proposed fix on my hardware (ESP32-C3 / ESPHome 2026.8.2) and report back.

Problem

The wavinAhc9000 component on main does not compile on the current stable ESPHome 2026.8.2. Both wavinAhc9000.cpp and wavinAhc9000_climate.cpp fail with:

wavinAhc9000.h:18:10: error: 'void ...::on_modbus_data(const std::vector<uint8_t>&)' marked 'override', but does not override

Cause

main currently targets the 2026.7.x ModbusClientDevice hook names (on_modbus_data / on_modbus_no_response / on_modbus_not_sent). In the released 2026.8.x API these were renamed and now take the request PDU as an argument. The relevant base-class declarations in modbus.h (2026.8.2) are:

virtual void on_response(std::span<const uint8_t> request_pdu, std::span<const uint8_t> response_pdu);
virtual bool on_no_response(std::span<const uint8_t> request_pdu);
virtual void on_not_sent(std::span<const uint8_t> request_pdu);

The earlier (reverted) commit cfdda97 already ported to on_response() / on_no_response() / on_not_sent(), but it was written against a pre-release 2026.8 master where the latter two took no arguments. Released 2026.8.2 added the request_pdu parameter, so those two now fail to override (compiler reports them as hidden via -Woverloaded-virtual).

Suggested fix

Use the cfdda97 port and add the request_pdu parameter to the two hooks so they match released 2026.8.2:

wavinAhc9000.h

void on_response(std::span<const uint8_t> request_pdu, std::span<const uint8_t> response_pdu) override;  // already correct
bool on_no_response(std::span<const uint8_t> /*request_pdu*/) override;
void on_not_sent(std::span<const uint8_t> /*request_pdu*/) override { this->waiting_ = false; }

wavinAhc9000.cpp

bool WavinAhc9000::on_no_response(std::span<const uint8_t> /*request_pdu*/) {

The bodies don't need the argument, so it can stay unnamed. send_pdu() still works but is deprecated in favour of queue_pdu() (removal announced for 2027.2.0), so that could be switched at the same time to silence the warning.

Environment

• ESPHome 2026.8.2 (HA add-on)
• Board: esp32-c3-devkitm-1, framework esp-idf 5.5.5
• Also requires flow_control_pin on the modbus: hub (as noted in cfdda97); rw_pin on the component is deprecated/ignored.

[nic6911]

which .yaml are you trying to compile based on?