V2/Persistence/PersistedTypeAttribute.cs
Attribute type that marks a concrete payload type with a stable persistence identity. It stores a string Id (validated via PersistedTypeKey) and a positive integer Version, and throws if version is <= 0.
#nullable enable
using System;
namespace Hexagon.V2.Persistence;
/// <summary>
/// Documents the stable persistence identity of a concrete payload type.
/// This marker never triggers discovery: schemas must still register a matching
/// typed codec and immutable-publication function explicitly.
/// </summary>
[AttributeUsage( AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false )]
public sealed class PersistedTypeAttribute : Attribute
{
public PersistedTypeAttribute( string id, int version )
{
Id = new PersistedTypeKey( id ).Value;
if ( version <= 0 )
throw new ArgumentOutOfRangeException( nameof(version), "Persisted type versions start at one." );
Version = version;
}
public string Id { get; }
public int Version { get; }
}