IDE unresponsive when uploading with Serial Monitor open and the board printing messages with no delays

[ubidefeo]

Behaviour:
If i have a sketch with a Serial.println("hello") in the loop with no delays, and the Serial Monitor is open,
If I initiate an upload the IDE stops being responsive and almost comes to a halt.
There's no recovery from it, I just have to quit and reopen

How to reproduce:

• Make a sketch with Serial.println("Hello!"); in the main loop.
• Upload it
• Open the Serial Monitor
• While Serial Monitor is printing out the message click upload again

System:
Mac OS
Version: 2.0.0-beta.1-snapshot.98ef006

[ubidefeo]

@per1234 I commented on Issue https://github.com/arduino/arduino-pro-ide/issues/424
not sure the two are related, but unless I have the SM open I don't get any slow-downs with compile/upload verbose enabled

[kittaakos]

• Make a sketch with Serial.println("Hello!"); in the main loop.

First, I wanted to check how the Java IDE behaves. I did the followings:

• Connect and select my Uno board,
• Compile and upload my sketch,

void setup() {
}

void loop() {
 Serial.println("hello");
}

• Opened the SM.
• Nothing happened.

Can you please share your sketch? Thank you!

[ubidefeo]

@kittaakos you are missing initialising the Serial first

void setup() {
  Serial.begin(9600);
}

void loop() {
 Serial.println("hello");
}

[kittaakos]

https://github.com/arduino/arduino-pro-ide/issues/294 is most likely required for this issue. The serial monitor is a custom rendered nightmare; the VS Code guys did a great job optimizing the monaco editor's performance. I will try to replace it.

---

One thing I have noticed, if you turn the auto-scroll off in the widget, the UX becomes much better.

Can someone please also verify it?

[rsora]

One thing I have noticed, if you turn the auto-scroll off in the widget, the UX becomes much better.
Screen Shot 2021-02-12 at 10 46 46

Can someone please also verify it?

Unfortunately, I've tested this on windows and I don't see any particular improvement, disabling the auto-scroll 😿

[kittaakos]

Upstream issue: eclipse-theia/theia#9063