Datapack Debugger

Datapack Breakpoint

Introduce

This is a fabric mod for Minecraft 1.21, which allows you to set breakpoints in the game and “freeze” the game when
the breakpoint is reached.

Usage

• Set a breakpoint

In datapack, you can insert #breakpoint into .mcfunction file to set a breakpoint. For example:

#test:test

say 1
say 2
#breakpoint
say 3
say 4

In this case, after the game executes say 2, the game will be “frozen” because it meets the breakpoint.

When the game is “frozen”, you can still move around, do whatever you want, just like execute the command tick freeze.
So you can check the game state, or do some debugging.

• Step

When the game is “frozen”, you can use the command /breakpoint step to execute the next command. In above example,
after the game meets the breakpoint, you can use /breakpoint step to execute say 3, and then use /breakpoint step
to execute say 4. When all commands are executed, the game will be unfrozen and continue running.

• Continue

When the game is “frozen”, you can use the command /breakpoint move to unfreeze the game and continue running.

• Get Macro Arguments

By using /breakpoint get <key>, you can get the value of the macro argument if the game is executing a macro function.
For example:

#test:test_macro

say start
#breakpoint
$say $(msg)
say end

After executing function test:test_macro {"msg":"test"}, we passed the value test to the macro argument msg and
then the game will pause before $say $(msg). At this time, you can use /breakpoint get msg to get the value test.