Print null instead of string

[jupvfranco]

In the program below, the main class creates many passive objects, of type Image,
which are initialized always with the same name "blah".
Each object of type Image is sent to a new active object of type Processing, which prints
the name of the image.

When I execute this program, the output is something like:

blah
blah
blah
...
blah
(null)
blah
blah

blah
...

nulls and empty lines are being printed and it shouldn't happen.
Thanks.

class Main

    def main(): void {

        let 
            n  = 10000
        in {
            repeat i <- n {
                let p = new Processing in 
                p!run(new Image(i))
            }
        }
    }

class Processing 

    def run(img: Image): void {
        print img.name
    }

----- passive data -------

passive class Image
    name: string
    n: int

    def init(n: int): void {
        this.name = "blah";
        this.n = n
    }

[TheGrandmother]

Hmm.. interestingly this only seems to cause problems when printing the strings and not the integers.

If I change run to:

    def run(img: Image): void {
        print("{}:{}\n",img.name,img.n);
    }

I get output which looks like:

blah:960
:959
blah:962
blah:961
blah:964
blah:963
blah:966
...
...
...
blah:990
blah:989
blah:992
(null):991
blah:994
blah:993

[supercooldave]

Probably a GC problem.
I bet if you create the Image inside the run method the problem will go away.
(Not that this solves the problem.)

[EliasC]

I agree with @supercooldave that the GC is the most likely cause. (null) is what printf prints if asked to print NULL as a %s. The blank lines could be that the actual string has been zeroed out, making it look like an empty string.

[TheGrandmother]

This bug may be related to #48

It the blank lines appears at regular intervals and the problem only occurs when n exceeds a certain value.

I had a similar problem with the same characteristics and that was due to the GC so I would not be surprised if this bug is related to the GC.

[EliasC]

As far as I can tell, this seems to be fixed now. My guess is the updated GC from 2ba9fb1 solved the problem. I'm closing this.