OTA text error messages lost due to multiple USB packets

[earlephilhower]

Ref: earlephilhower/arduino-pico#787

Basically, OTA::printError is calling printf() multiple times, causing multiple UDP packets to be sent to espota.py.

espota will throw out anything after the first packer with a E (i.e. ERROR) meaning the text messages are lost.

Simple fix is to concat the errors into a String prior to sending, then use a single out.println() call.

[mcspr]

...could be taken from https://github.com/esp8266/Arduino/pull/8653/files
maybe even with the additional String-returning method

[earlephilhower]

👍

The title "Updater lifetime callbacks" didn't really cover this but I see it's part of the changed, but thx for pointing it out! I'll close this, no worries.

Just trying to keep track of things I find in the Pico and make sure they are covered upstream!

[mcspr]

It is complicated, yes:)

Just checking, I don't see error string being pushed multiple times in this implementation as everything is buffered in StreamString first

Arduino/libraries/ArduinoOTA/ArduinoOTA.cpp

Lines 253 to 257 in 313b3c0

	StreamString ss;
	Update.printError(ss);
	_udp_ota->append("ERR: ", 5);
	_udp_ota->append(ss.c_str(), ss.length());
	_udp_ota->send(ota_ip, _ota_udp_port);

This part seems to do this in sync-mode, but not sure if it matters

Arduino/libraries/ArduinoOTA/ArduinoOTA.cpp

Line 342 in 313b3c0

Update.printError(client);