Nothing has ever read it. The slot count comes from two other places: the
persisted array size (MAX_MQTT_SLOTS / RUNTIME_MQTT_SLOTS in MQTTPresets.h) and
the runtime cap MQTTBridge::getMaxActiveSlots(), which answers 5 with PSRAM and
2 without. A flag reading MAX_MQTT_BROKERS=3 sitting in every observer env
implies a third, lower limit that does not exist — it cost me a wrong answer
about how many MQTT slots a Heltec V4 exposes.
36 lines across 15 variants, all of them =3. Removing an unread -D cannot change
code: heltec_v4_repeater_observer_mqtt builds to a byte-identical size before and
after (1647744). The image checksum does differ, but so does it between two
clean builds of untouched source — ESP-IDF stamps the app descriptor with the
build time — so size is the meaningful comparison here.
All 606 envs still parse; heltec_v4, heltec_v3, station_g2, rak3112 and
xiao_s3_wio observer targets all build.
Adds ThinkNode_M7_repeater_observer_mqtt and
ThinkNode_M7_room_server_observer_mqtt, following the Station G3 observer
overlay: adafruit-full cert bundle, MQTT bridge + SNMP, pinned observer
lib_deps, and the quieter default logging profile.
WiFi-only for now. The M7 has an onboard CH390 Ethernet controller (used by
ThinkNode_M7_companion_radio_ethernet, and an lwIP netif so the MQTT data path
would work over it), but the bridge's link management is bound to the WiFi
station API, so Ethernet cannot carry MQTT yet.
The board has PSRAM, so MAX_NEIGHBOURS=50 enables WITH_MQTT_NEIGHBORS —
verified present in both images. Builds use 46.5% of the 3.19 MB app slot at
13.7% RAM, and build.sh emits the full artifact set (.bin, -merged.bin,
.partsig). The partition table is inherited from [ThinkNode_M7] unchanged, so
no merged first flash is needed; its signature is byte-identical to the T-Beam
Supreme observer builds (both default_8MB.csv).
Also fixes two pre-existing build failures on this board:
- [ThinkNode_M7] re-added a blanket helpers/*.cpp after arduino_base excludes
the MQTT-only sources, so every M7 env failed on a missing Timezone.h. The
glob was otherwise fully redundant with the base, so it is dropped rather
than re-excluding the two files.
- ThinkNode_M7_companion_radio_ethernet sets DISPLAY_CLASS=NullDisplayDriver
but never compiled NullDisplayDriver.cpp, which defines UIColor::window_bkg,
so it failed at link. The ble and wifi envs both already list it.
All nine M7 envs now build. Observer env discovery picks up both new envs, and
the ArduinoJson pin check covers both new sections.
mikecarper