Potential Memory Leak w/ function local variables

[PhilCCMG]

Description

When writing functions (not procedures), storing local variables are potentially causing a memory leak as they do not appear to be deleted once the function returns a value.

Steps to Reproduce

1. Write a function which is often called setting numerous variables, for example

function orderLore(i: item) :: item:
    set {_lore::*} to lore of {_i}
    set {_hasce} to false
    set {_enchants} to ""
    loop {_lore::*}:
        set {_b} to loop-value
        replace all "&a" and "&b" with "" in {_b}
        set {_b::*} to {_b} split at " "
        set {_b} to {_b::1}
        {_enchants::*} contains {_b}:
            {_enchants} is "":
                set {_enchants::*} to "%loop-value%"
            else:
                set {_enchants::*} to "%{_enchants}%", "%loop-value%"
        else if loop-value contains "Rarity: ":
            set {_rarity} to loop-value
        else:
            size of {_other::*} is 0:
                set {_other::*} to "%loop-value%"
            else:
                add "%loop-value%" to {_other::*}
    set {_lore::*} to {_enchants::*}, {_other::*}
    set {_i}'s lore to {_lore::*}
    return {_i}

2. Run the function on a consistent basis every few seconds.
3. After approximately 1-2 hours, the server will start to dramatically spike in RAM usage.

Expected Behavior

Local variables should be fully deleted from the RAM and the server should not keep tracking them.

Errors / Screenshots

Here is a screenshot of the Eclipse Memory Analyser taken during a lagspike.

Server Information

• Server version/platform: 1.12.2 Paper
• Skript version: Skript 2.4

Additional Context

Potentially similar to #2337, though it is marked as closed before 2.4 was released.

[JRoy]

Can you reproduce this in 2.5-alpha2?

[PhilCCMG]

I'll give it a shot - as stated it takes up to two hours to reproduce as it accumulates and only seems to start after a certain amount of time, but will try.

[PhilCCMG]

Server isn't even booting; has this error about 50 times on 2.5-alpha2
https://hastebin.com/erehihudin.cs

[bensku]

Please try without addons, this should have been fixed before 2.4 was released.

[PhilCCMG]

Hard to tell if it's directly continuing without addons but appears to be.

[PhilCCMG]

From digging into a heapdump in a bit more detail, it seems to be setting a variable to something split, for instance:

set {_lore::*} to player's tool's lore
loop {_lore::*}:
    set {_lines::*} to loop-value split at " " # This seems to be causing the leak

[PhilCCMG]

I'm mistaken.

The {_lore::*} variable from above was set 16 million times after 4 hours of uptime. I'd presume the local variable isn't being deleted when in list form.

[PhilCCMG]

As an example, however, we see {_lore::*} is being stored 300,000 times in RAM which shouldn't be happening.

[ham1255]

after doing testing with @Govindass quick solution is to delete local variable at the end of a code
like showing below.

delete {_receivers::*}

[Whimsyturtle]

I'm not sure if this issue is the same as the issue that I reported in #2337, but it seems like #2337 is still an issue in Skript 2.5-alpha3.

[Whimsyturtle]

Closing in favor of #2337, to consolidate this issue.