godot: str2var crashes the application when processing a non-convertible string - not very useful behavior

A common use case for str2var for me is to have it go through a collection of string variables and have it convert them to the appropriate type. This however becomes a problem, as str2var will crash godot if it encounters a variable that is supposed to be a string in the first place.

I think it would be more useful if the function simply returns the original input string in that case, rather than crashing the engine.

I made an ugly workaround function to get around that- just to stop it from crashing:

func cusStr2Var(inputString):
	if !isItAString(inputString):
		return str2var(inputString)
	else: return inputString

func isItAString(string): ##fixed
	var NameRegEx = RegEx.new()
	NameRegEx.compile('[A-Za-z]+')
	if NameRegEx.search(string) != null:
		return true
	else: return false

Its messy, might have to rewrite it, the idea is to avoid crashing

But would really like it if I didn’t have to 😃 If you want to keep the crash message as to why it failed to convert it, why not turn it into a warning instead?

About this issue

Original URL
State: closed
Created 7 years ago
Comments: 15 (10 by maintainers)

Commits related to this issue

GDscript function str2var now returns input string on invalid input str2var used to raise a blocking error when invalid input was passed. Now it logs an error message and returns the input string. T... — committed to rxlecky/godot by rxlecky 6 years ago

Most upvoted comments

Actually, returning the original string sounds like the best solution. You can compare the input and the output and if they’re the same it means the parsing failed.

vnen on Dec 21, 2017

No, I think it should be changed only for GDScript (since this is a GDScript-only function), so just change this if block to just return the original argument instead of creating an error:

https://github.com/godotengine/godot/blob/1fa9aac3e415f53a095e955c8a37000629d56dde/modules/gdscript/gdscript_functions.cpp#L702-L708

People using the VariantParser directly can detect the error themselves.

vnen on Dec 21, 2017

I’m not necessarily opposed to changing things to prevent a crash, but I don’t think a second parameter is the answer in this case. A more efficient solution might be to have it return an ERR_* integer in case of failure. Doesn’t seem as though it would be that difficult to implement. Granted, I don’t know how it’s string parsing works or whether it can be evaluated in advance, prior to the crash check.

willnationsdev on Dec 21, 2017

For one side it’s good to have it error, since it can avoid bugs. OTOH this current behavior makes it impossible to recovery, since Godot offers no error handling.

I don’t like returning the original string, it makes impossible to know if it was a success or not. TBH this is also the case for null, it’s totally possible to the original value was a Null since typeof(str2var('null')) == TYPE_NIL is true.

Also note that for a string to parsed correctly, it needs to be enclosed in double-quotes: print(str2var('"This will print nicely"')).

vnen on Nov 19, 2017