Lesson 22, Practice 1 - Persistent Freeze during Run assessment

[MysticAndMuse]

gdquest-1774819456854.log

Description
While an incorrect answer to the code produced the expected error report and allowed me to continue working within the app just fine, getting the answer right (I believe - see screenshot) and pressing Run has caused the app to irrevocably freeze at the exact point shown in the image. The animations play to the point of summoning the toast order and its loading bar to about half way, and then the app hoses. Nothing is interactable in any of the menus or toolbars - the browser window must be refreshed entirely and Lesson 22 itself is reloaded from the start upon selecting "Continue".

To Reproduce

• I refreshed the page and reproduced this three times, once after updating and restarting the Chrome browser just in case that was presenting the issue.
• Lesson 22 has few interactive elements, and I skipped them upon scrolling through to get to Practice 1 on subsequent reloads. It made no difference.
• The code I've entered into the code window has been exactly the same each time before pushing Run and the app has frozen, as I believe this to be the right answer. I had one error/failure to start, which was a typo on "waiting_orders.pop_front()" where I left out the "s" on "orders". Running this incorrect iteration went fine though. The freeze only happened once I fixed the typo. It then happened again and again no matter how I refreshed the browser.

Expected behavior
App was expected to complete assessment animation and give practice code either an all-clear or some kind of error notes.

My Device:

• Operating System: Decently new Windows 11 gaming desktop
• Browser: Chrome, fully up to date

Additional context

• Minimal tabs are open and only low memory, passive apps are running on the device at the time of the freeze
• The rest of the Chrome browser and PC continues to function fine, regardless of the Learn GDScript app's behavior
• I'm going to assume I got it right and move on, but I hope this is useful is some way for catching a bug

Thank you for the lessons! I do love the integrated game-making style, and would like to see it running smoothly.

[NathanLovato]

Related: #960

[NathanLovato]

This specific issue is addressed by #1248

[NathanLovato]

@Razoric480 when testing the code above that would freeze in Godot 3, I get the generic error "The script has an error, but the script verifier did not catch it." Could you please check this?

Direct link to practice: https://gdquest.github.io/learn-gdscript/staging/#course/lesson-23-append-to-arrays/practice-KUdOCQiG.tres

Complete code listing for easy copy paste:

var waiting_orders = []
var completed_orders = []

func complete_current_order():
	var completed_order = waiting_orders.pop_front()
	completed_orders.append()

[Razoric480]

Godot 3

When GDScript::reload is called, it runs it through the GDScriptParser, then the compiler. Both pass, then it tries to run code and calls append() without an argument. The app breaks, but because we're in debug mode it just kind of holds at verification, until the yield timer kicks in to force-finish the verification.

We don't really have an opportunity to catch this issue unless we start peppering information about the internal API and look for it specifically, which is not particularly tenable.

So this is will-not-fix while we're still on Godot 3.

Godot 4

When GDScript::reload is called, it runs it through the GDScriptParser, then a GDScriptAnalyzer, then the compiler.

The Error Checker runs the parser, but not the analyzer, where things like this end up failing. Because reload() returns error 43 (ERR_PARSE_ERROR), then we give a generic "failed to parse" error. But at least the app doesn't crash - it just doesn't tell the student anything about why it failed unless they go on discord to ask for help.

I can recompile the engine to include the analyzer when doing an error checker test, which would fix this with actual error messages.

[NathanLovato]

If we can have the analyzer running and catch more error messages, that would actually be great. You can definitely give it a try!