strings in arenas causes leak

[tedhorst]

This program compiles cleanly and runs, but aborts at the end with a leak message. Changing str to int does not leak.

use std;
import std::arena;
import std::arena::arena;

enum hold { s(str) }

fn init(ar: &a.arena::arena, str: str) -> &hold {
    new(*ar) s(str)
}

fn main(args: [str]) {
    let ar = arena::arena();
    let leak = init(&ar, args[0]);
    alt *leak {
        s(astr) {
            io::println(#fmt("%?", astr));
        }
    };
}

rust: fatal, 'leaked memory in rust main loop (1 objects)' failed, ../src/rt/memory_region.cpp:169 1 objects
Abort trap: 6

[catamorphism]

To get this to compile with 552677e I had to change &hold to &a.hold in the return type of init. But then I found that it leaked whether with str or with int. That exhausts the limits of what I understand about this -- assigning.

[catamorphism]

Confirmed that this is still a bug as of 6/21/2012.

[graydon]

It does not leak with int. Which is correct behavior. It's not good behavior, but it's correct. This is because arenas don't do any cleanup on their contents, they just drop all the allocated memory. You have a unique-owning string you allocated the owning-pointer for in an arena. So it leaks when it's dropped.

[tedhorst]

So is there a way to get the string itself allocated in the arena?