Second level cache key mismatch

[gokhanabatay]

When using a distributed second level cache relying on cache key binary serialization, the keys do not
match across .Net Core processes. They also do not match inside a same process when the keys include filters.

Original report

Hi,
When I use Contextual Filters it tries to retrieve from cache but cached query and current query session filter does not matches.
But it's actually are the same filter when I call ISet.ToString() I can see and I know that they are same filters. It needed to be retrieved from cache below sample.

http://nhibernate.info/doc/howto/various/contextual-data-using-nhibernate-filters

Anyway when I debug the nh I see the error QueryKey.cs line : 130

if (!CollectionHelper.SetEquals(_filters, that._filters))
{
	return false;
}

Somehow the above code does not call FilterKey Equals method when HashSet SetEquals called.
It just call overrided GetHashCode metod of FilterKey class.

When I changed above code to below code it runs like charm.

if (!CollectionHelper.SequenceEquals(_filters, that._filters))
{
	return false;
}

[gokhanabatay]

@hazzik please let me an option to fix this issue.
@fredericDelaporte as you say that the issue is GetHashCode function. Let me tell you.
I debug all .net core HashSet among other class there are lots of codes...

Below code CoreDistributedCache line 232 at Deserialize calls our "FilterKey GetHashCode" method and "_filterParameters" is empty when it called. And wrong HashCode is calculated and stored at HashSet local variable.
This is the issue that your test does not effected and succeeded but in life scenario it fails, because in your test you do not deserialize Filters you just initialize them.

var serializer = new BinaryFormatter(); using (var stream = new MemoryStream(cachedData)) { var entry = serializer.Deserialize(stream) as Tuple<object, object>; return Equals(entry?.Item1, key) ? entry.Item2 : null; }

FilterKey
public override int GetHashCode() { var result = 13; result = 37 * result + _filterName.GetHashCode(); result = 37 * result + CollectionHelper.GetHashCode(_filterParameters, NamedParameterComparer.Instance); return result; }

As a Result I think best solution is SequenceEquals because it does not care HashCode it just cares Equals method and it works like charm as i said :) I Ordered filters for your tip.

if (!CollectionHelper.SequenceEquals(_filters?.OrderBy(x=>x.ToString()) , that._filters?.OrderBy(x=>x.ToString()))) { return false; }