The following code segfaults, when the outer hashmap rehashes,
and I am not yet sure why.

module tests.refcounted_hashmap_test;

import containers;
import std.typecons;

struct Map
{
    HashMap!(int, int) theMap;
}

unittest
{
    HashMap!(int, RefCounted!Map) mapOfMaps;
    foreach (i; 0 .. 1000)
    {
        RefCounted!Map val;
        if (i == 0) val.theMap.getOrAdd(i, i);
        mapOfMaps.getOrAdd(i, val);
    }
}

For your convenience: https://run.dlang.io/is/gHSlu1

I am using Refcounted() because HashMap itself is not copy-able. Is there another way to have HashMaps as values of HashMaps?

On Sunday, 2 May 2021 at 07:38:03 UTC, Tobias Pankrath wrote:

module tests.refcounted_hashmap_test;

import containers;
import std.typecons;

struct Map
{
    HashMap!(int, int) theMap;
}

unittest
{
    HashMap!(int, RefCounted!Map) mapOfMaps;
    foreach (i; 0 .. 1000)
    {
        RefCounted!Map val;
        if (i == 0) val.theMap.getOrAdd(i, i);
        mapOfMaps.getOrAdd(i, val);
    }
}

HashMap!(int, RefCounted!Map) mapOfMaps = HashMap!(int, RefCounted!Map)(1024);

On Sunday, 2 May 2021 at 08:59:15 UTC, Imperatorn wrote:

HashMap!(int, RefCounted!Map) mapOfMaps = HashMap!(int, RefCounted!Map)(1024);

Is HashMap.init a broken state? That makes using them hard as struct members :/

On Sunday, 2 May 2021 at 08:59:15 UTC, Imperatorn wrote:

HashMap!(int, RefCounted!Map) mapOfMaps = HashMap!(int, RefCounted!Map)(1024);

That only fixes it, because you are avoiding the rehash with the
initial size.

On Sunday, 2 May 2021 at 07:38:03 UTC, Tobias Pankrath wrote:

I've figured it out and filed an PR https://github.com/dlang-community/containers/pull/169. Would be great if we can get a new version out with this.