Add INFINITE_LOOP_TRAP back to non-Maze app types

[joshlory]

Some interesting history here:

• Blockly.JavaScript.INFINITE_LOOP_TRAP was renamed to BlocklyApps.INFINITE_LOOP_TRAP almost 5 years ago, accidentally breaking Blockly's built-in infinite loop detection.
• Someone noticed that we didn't seem to have infinite loop detection and updated the comment. But that comment was later removed 😂.

I picked half a million steps sort-of-arbitrarily. It takes about 5 seconds to catch the infinite loop. I tried to balance user experience (don't freeze the browser too long) against not cutting off programs early that draw complex things.

The thrown exception is caught here:

code-dot-org/apps/src/turtle/artist.js

Lines 693 to 696 in ba8124e

	} catch (e) {
	// Infinity is thrown if we detect an infinite loop. In that case we'll
	// stop further execution, animate what occurred before the infinite loop,
	// and analyze success/failure based on what was drawn.

[Hamms]

Circle failure looks legit.

Does this play nicely with *labs levels that we expect to run for >5e5 ticks?

[joshlory]

Play Lab goes through the CustomMarshalingInterpreter.evalWithEvents path. This should only affect Artist, Craft, Eval & Calc which use CustomMarshalingInterpreter.evalWith.

[Hamms]

Awesome! Have you verified the timeout against some of the longer artist drawings? And can we also remove the maze special case for this?

[joshlory]

It looks like codegen is wrong for functional_definition blocks 🙄 when INFINITE_LOOP_TRAP is non-empty:

Globals.f = function(x) {
return   executionInfo.checkTimeout(); if (executionInfo.isTerminated()){return;}
  (  x +   1)
}
; return(  (  2 +   1) ==   Globals.f(  2))

[joshlory]

@Hamms PTAL!

[Hamms]

I'm still worried about the impact this will have on the longer artist drawings, particularly the really cool fractal ones

[joshlory]

Hmm — 500,000 steps is a lot. A program like that would noticeably hang most browsers. What cutoff do you think is best?

[Hamms]

Oh dang, right you are. Even https://studio.code.org/projects/artist/Ut6coOwiXo_fg_B6Eh2CAA/edit only takes ~50k steps.

Worry sated! This LGTM