gather-take leaks memory

[bbkr]

raku -e 'use Telemetry; my @s = lazy gather loop { take rand x 1024 }; for @s { say T{"max-rss"} }'

It looks like taken values are not disposed properly - the bigger the values the bigger memory leak.

# raku -v
Welcome to Rakudo™ v2022.07.
Implementing the Raku® Programming Language v6.d.
Built on MoarVM version 2022.07.

[bbkr]

Same for 2022.12, but the leak seems to be slower here.

[ab5tract]

Memory usage is stable when using $s := instead of @s =:

> r 'use Telemetry; my $s := lazy gather loop { take rand x 1024 }; for $s { say T{"max-rss"} }'
146
...
146
> ./rakudo-m -v
Welcome to Rakudo™ v2024.04-92-g24057e69c.
Implementing the Raku® Programming Language v6.d.
Built on MoarVM version 2024.04-6-g84121f0de.

Not sure whether that classifies this into DIHWIDT territory or not...

[bbkr]

Uh, I kind of feel stupid now...

$ raku -e 'my @s = lazy gather loop { take rand }; say @s[3]; say @s[4]; say @s[3];'
0.5002519799798362
0.9103084169123906
0.5002519799798362 # this is materialized

I have no idea why I thought @s will keep lazy Seq itself without binding. So yes, DIHWIDT :)