Breakpointing in dev mode causes computers to stop working

[uecasm]

Minecraft Version

1.16.x

Version

1.100.4

Details

In a mod development environment, with a peripheral method tagged with @LuaFunction(mainThread = true), placing a breakpoint inside the method and quickly stepping through works ok, but if left stopped at the breakpoint for several seconds, after resuming execution the method completes but its output is not returned to the lua code.

Running a second such method after this timeout occurs locks up the lua interpreter without executing the peripheral method; it does still respond to Ctrl-T/Ctrl-R etc and standard methods continue to work, but there does not appear to be any way to allow it to call mainThread methods again without restarting the entire Minecraft server.

[SquidDev]

CC attempts to limit the amount of work a computer can do on the main thread each server tick, giving each computer a budget of 5ms/tick and a global budget of 10ms/tick. When you break within a method, you're obviously stopping for a bit more than that, which means it takes 1000s of seconds for the computer to "cool down" again.

There's a couple of config options you can adjust to increase that limit - setting it to Integer.MAX_VALUE effectively disables this functionality entirely.

CC-Tweaked/src/main/java/dan200/computercraft/shared/Config.java

Lines 149 to 159 in 87a1c1a

	maxMainGlobalTime = builder
	.comment( "The maximum time that can be spent executing tasks in a single tick, in milliseconds.\n" +
	"Note, we will quite possibly go over this limit, as there's no way to tell how long a will take " +
	"- this aims to be the upper bound of the average time." )
	.defineInRange( "max_main_global_time", (int) TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainGlobalTime ), 1, Integer.MAX_VALUE );
	maxMainComputerTime = builder
	.comment( "The ideal maximum time a computer can execute for in a tick, in milliseconds.\n" +
	"Note, we will quite possibly go over this limit, as there's no way to tell how long a will take " +
	"- this aims to be the upper bound of the average time." )
	.defineInRange( "max_main_computer_time", (int) TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainComputerTime ), 1, Integer.MAX_VALUE );

[uecasm]

I tried changing those two settings to 2147483647, but it didn't make any difference.

Besides, it seems like it ought to recognise a silly large cooldown and just reset it.

[SquidDev]

No clue then I'm afraid. You could try stepping inside the MainThread class and see what's going on.

[uecasm]

Apparently pausing it for a few seconds measures a time of 45676833400, so it still exceeded that limit.

Setting them to 1152921504606846976 instead seems to work. (Which is not Long.MAX_VALUE but is close enough given that it still does maths on the value.)