Maintain a list of changed parameter/calculation names

[gerw]

Guzz-T noted in #132 that we have changed some names since 0.3.14, in particular, Unknown_Calculation_239 has been changed to VBO_Temp_Spread_Soll. I suspect that this will also happens many times in the future.

Users of our library will find that Unknown_Calculation_239 will no longer work after an update and in some occasions, it might be quite cumbersome to find out the new name. (For Unknown_Calculation_239 it is pretty obvious, that this is calculation 239, but in other cases this might not be true).

I think that we should maintain a list of changes of these names, i.e., something like

changed_names = {
    "Unknown_Calculation_239" : "VBO_Temp_Spread_Soll"
}

in constants.py. Then, DataVector._lookup could also resolve old names (and maybe spit out a warning that users can change their code?).

• If we do so, we should also set up a unit test, which assures that all old names can be resolved.
• There seems to be one limit to the approach: We can't resolve the situation where "ID_BarFoo" is mapped to parameter 42 in 0.3.14 but is mapped to 23 in 0.3.15. However, this does not seem to be a big deal, since we can (almost) freely choose the parameter names.
• What about ID_WEB_SoftStand? This old calculation will be replaced by a higher level function. I think that an access of this old name should result in a meaningful error message. Maybe we can add a dictionary obsolete_names which contains these error messages, e.g.,

obsolete_names = {
    "ID_Web_SoftStand" : 'This parameter has be replaced by the function "get_firmware_version()" of LuxtronikData / Luxtronik.'
}

[Guzz-T]

If we still support old names, do we also have to support older luxtronik firmware versions? For example the used-energy-value is only available within the (current) latest firmware version. But not in previous ones.

[gerw]

This issue is about compatibility of code that works with older library versions. For example, in 0.3.14 you could have

l.calculations.get("Unknown_Calculation_239")

and, as you observed, this no longer works with the present state of the library. This is totally unrelated to the firmware version of your luxtronik controller. I think that, ideally, code that works with old versions of the library still works with the newer versions. And if this is not possible, we should raise a meaningful error message.

I do not see any compatibility issues w.r.t. different firmware versions. Of course, some parameters/calculations are only available in certain versions, e.g., the calculation 257: Power("Heat_Output"), is only available in newer versions, while the support of the "MainMenuStatusLine" in calculations 117-119 was dropped a long time ago. I do not know any instance where the meaning of some entry changed its meaning, but there are a couple of instances, where a parameter/calculation is no longer active, i.e., it is always 0 (or we even see some noise) and writing to it doesn't change anything (besides the value itself). I assume that alpha innotec wants to avoid this, since that would lead to different complications related to their own software (the app, I think).

[Guzz-T]

I am aware that this question was a bit "off-topic". However, the library version is usually connected to the firmware version.

It was also more of a question whether it is worth creating a new issue instead of a request to change this here.