Implement lastCompute

[hatmatty]

There is currently an issue with the evaluate function.

In evaluate.luau look at the section of the code that decides whether a recompute is needed. Assume dependency.lastChange > target.lastChange is true for one of the dependencies.
Then when the computation is complete assume the new value is the same, so "targetMeaningfullyChanged" is false and target.lastChange does not update.

Then dependency.lastChange > target.lastChange will remain true and the target will keep updating unnecessarily when it has already been computed with the new value of the dependency.

A fix to this would be to introduce another property, lastCompute, which tracks the last time a stateobject was updated.

[parker02311]

Is there a reason this section was replaced with a print statement?
Or was it just left over from debugging?

[hatmatty]

Oh yeah that's a mistake. Good catch

[hatmatty]

an alternate way to do this without modifying a lot of the files would be to do

if target.lastCompute then
	if dependency.lastChange > target.lastCompute then
		needsComputation = true
	end
else
	if dependency.lastChange > target.lastChange then
		needsComputation = true
	end
end

in evaluate.luau, and then set lastCompute in the "if needsComputation" block.

[bytejon]

Can you provide an example (with code) to highlight this issue happening with the current behavior?