ESP32C3 - Serial appears to block the application

[thiccnfun]

From discord:

the esp32c3 I'm working with seems to halt execution or something unless there is a serial monitor connected. If I plug it into my PC, it seems to connect to wifi as expected, but the web ui (using the sveltekit build) is not accessible... However the moment I start a serial monitor the UI loads up.

Commenting/removing all references to Serial appears to resolve this issue.

The following files (excluding main.cpp) had Serial lines that were commented:

Maybe unique to the ESP32C3, or the Seeed Studio XIAO ESP32C3 board specifically.

[pletch]

For reference, I am running the same Seeed Studio board and didn't have to comment out the Serial lines as mentioned. After flashing and moving the board to stand-alone power supply, the web ui was not initially accessible but it did eventually come up when I checked again some time later. During inaccessible time, the board could have been in wifi AP mode rather than connected wifi STA mode but I didn't immediately investigate.

Only customizations I am using are a platformio.ini definition for the Seeed board (LED_BUILTIN assigned to GPIO4 arbitrarily):

board = seeed_xiao_esp32c3
board_build.mcu = esp32c3
board_build.partitions = min_spiffs.csv
build_flags = 
    ${env.build_flags}
    -DLED_BUILTIN=4```

[theelims]

HEAD now contains a buildflag -D SERIAL_INFO to enable or disable all Serial.print() statements.

The issue seems to be coming from the underlying Arduino libraries and is widespread. See
espressif/arduino-esp32#7554
espressif/arduino-esp32#8322