eraseConfig() passed SPIFFS.format() as an argument to THEENGS_LOG_TRACE,
which expands to ((void)0) below LOG_LEVEL_TRACE and discards its arguments
along with the call. On every build using the default LOG_LEVEL_NOTICE the
format therefore never ran, so {"cmd":"erase"} only performed
nvs_flash_erase(): the WiFi credentials were cleared but /config.json
survived and restored the MQTT server, port, user, password, broker and
client certificates, connection index, topic, gateway name, OTA password
and BLE AES keys on the next boot.
Call SPIFFS.format() on its own statement and report a failed format at
ERROR level, so the failure is visible at the default log level.
This was introduced in #2232, which converted the original runtime-checked
Log.trace() call to the compile-time macro. It affects the SYS erase
command, the WebUI erase button and the GPIO factory-reset hold alike,
since all three go through eraseConfig().
Reproduced on a Theengs Plug built at the default log level: after
{"cmd":"erase"} the NVS namespaces are gone ("SYS config not found",
"ONOFF config not found") and the saved APs are empty, yet the same boot
still logs "Config loaded from flash" and restores the OTA server cert.
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
