MQTT data for thermostat_data_hc2 corrupted

[majdaf]

Bug description

• EMS-ESP Version: v3.4.0b3
• Device (Platform / SDK): ESP32 / v3.3.5-1-g85c43024c

Thermostat data from RC310 are read correctly and are desiplayed on dashboard in UI. E.g. "hc2 selected room temperature" reads correct 20,0 C. The data gets passed to MQTT:
2022-02-07 20:01:36.504 D 108: [mqtt] Publishing topic ems-esp/thermostat_data_hc2 (#65272, retain=0, retry=1, size=395, pid=1)

However the data for HC2 passed to MQTT seem to be corrupted:
{"auto":20,"fort":20.2,"r":"auto","mized":"comfort","ecotemp":17,"manualtemp":21,"comforttemp":20,"summertemp":15,"designtemp":40,"offsettemp":0,"minflowtemp":25,"maxflowtemp":40,"roominfluence":10,"curroominfl":-0.8,"nofrosttemp":5,"targetflowtemp":29,"heatingtype":"floor","summersetmode":"auto","summermode":"off","controlmode":"optimized","program":"prog_2","tempautotemp":-1,"fastheatup":0}

This does not happend to HC 1 data coming from the same thermostat:
{"seltemp":20,"currtemp":20.2,"mode":"auto","modetype":"eco","ecotemp":19,"manualtemp":21,"comforttemp":22,"summertemp":15,"designtemp":65,"offsettemp":0,"minflowtemp":25,"maxflowtemp":65,"roominfluence":0,"curroominfl":0,"nofrosttemp":5,"targetflowtemp":46,"heatingtype":"convector","summersetmode":"auto","summermode":"off","controlmode":"optimized","program":"prog_1","tempautotemp":-1,"fastheatup":0}

Steps to reproduce
Connect EMS-ESP to EMS bus
Enable MQTT with HA auto discovery

Expected behavior
E.g. the seltemp are obvioulsy expected by the HA sensor/number defition:
{"~":"ems-esp","uniq_id":"thermostat_hc2_seltemp","command_topic":"~/thermostat/hc2/seltemp","min":5,"max":29,"step":0.5,"ic":"mdi:coolant-temperature","stat_t":"~/thermostat_data_hc2","name":"Thermostat hc2 selected room temperature","val_tpl":"{{value_json.seltemp}}","unit_of_meas":"°C","dev":{"ids":["ems-esp-thermostat"]}}

Context
MQTT setting:

• QoS: 0
• Set Clean Session: true
• Always use retain flag: false
• Topic/Payload format: As individual topics
• Publish command output to a 'response' topic: false
• Publish single value topics on change: false
• Enable MQTT Discovery (for Home Assistant, Domoticz): true
• Prefix for the Discovery topic: homeassistant

[proddy]

Thanks for reporting. I've reproduced this. Seems to only happen when the MQTT is not nested (default is nested and preferred). Working on a fix...

[MichaelDvP]

Seems there is a change in latest arduinojson. It works if not only the document, but also the jsonObject is cleared before reuse.
In EMSESP::publish_device_values( add to all doc.clear(); a json.clear();

[proddy]

thanks Michael, I was hunting down the root cause in the arduinojson library so I can report back an issue. It looks like it happens due to the flashstrings in parsing the enums.

[proddy]

bblanchon/ArduinoJson#1712

[MichaelDvP]

That's good, but as far as i understood the document stores the data and the object a reference to the keys. Clearing the object too do no harm and is maybe better because creating a key in cleared structure dont need to search for existing keys if the structure is not cleared.

[proddy]

I wanted to avoid using JsonObject.clear() because of memory leaks https://arduinojson.org/v6/api/jsonobject/clear/

I solved it now by not using clear() and re-assigning the JsonObject each time since doc.to<JsonObject>() also implicitly clears the pool and this way we don't lose the reference.

[MichaelDvP]

The memory leak is only if you clear the object without clearing the document. But recreating the object is a clean solution.