async-mqtt-client compiled and linked in when WLED_DISABLE_MQTT is set

[rhkean]

What happened?

I just noticed that the async-mqtt-client is compiled and linked into the bin even when the WLED_DISABLE_MQTT flag is set.

by deleting the entire folder from the src/dependencies folder, the bin file is 3.2k smaller

To Reproduce Bug

add -D WLED_DISABLE_MQTT flag to platformio.ini file
build the project
notice that the async-mqtt-client is still listed as being compile and linked

delete the async-mqtt-client folder from the src/dependencies folder
see that the bin is 3200 bytes smaller

Expected Behavior

async-mqtt-client is not linked and/or included in the .bin file

Install Method

Self-Compiled

What version of WLED?

WLED 0.15.1.beta2

Which microcontroller/board are you seeing the problem on?

ESP32

Relevant log/trace output

Anything else?

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[blazoncek]

@willmmiles could you take a look what's causing it? I peeked into ELF and can see some AsyncMqttClient references but can't make anything useful from it.

[willmmiles]

@willmmiles could you take a look what's causing it? I peeked into ELF and can see some AsyncMqttClient references but can't make anything useful from it.

The linker always includes .cpp files that are part of the project itself -- only those in static libraries are filtered based on whether or not there are external references. The assumption is that you could have important work being done in static constructors, for example.

IMO the best fix is to un-vendor the library, and call upon the latest version from upstream via lib_deps; I'm pretty sure there's been quite a few fixes since it was vendored in here ...

The second-best fix is to move it to the "lib" folder, import a proper library.json (ideally from the upstream project), and add it to lib_deps.

Giving the dependencies some love is next on my list after usermod wrangling. I've still got that old ArduinoJSON v7 branch kicking around, too...