ModernUO/dev-docs/claude-skills/migrate-from-runuo/migrate-serialization.md

name	description
migrate-serialization	Trigger: when converting RunUO Serialize/Deserialize methods, adding [SerializableField], converting [Constructable] to [Constructible], or migrating manual serialization code. Covers: source-generated serialization, field conversion, version handling, TypeAlias.

RunUO -> ModernUO Serialization Migration

When This Activates

• Converting Serialize(GenericWriter)/Deserialize(GenericReader) overrides
• Converting [Constructable] to [Constructible]
• Adding [SerializableField] attributes
• Handling save compatibility with [TypeAlias]

Conversion Steps

1. Add using ModernUO.Serialization;
2. Read the old Serialize() to find the version number it writes. Bump it by 1 for [SerializationGenerator]
3. If old Deserialize() used reader.ReadInt() (not ReadEncodedInt()), pass false as second parameter: [SerializationGenerator(N, false)]
4. Add partial to class declaration
5. Convert each serialized field: private int m_X -> [SerializableField(N)] private int _x
6. Add [SerializedCommandProperty(AccessLevel.X)] if RunUO had [CommandProperty]
7. Add [InvalidateProperties] if setter called InvalidateProperties()
8. DELETE the Serial constructor
9. DELETE the Serialize() override
10. Convert Deserialize() to private void Deserialize(IGenericReader reader, int version) to handle pre-codegen saves (remove override, base.Deserialize(), and version read line). Delete entirely if no existing saves.
11. Change [Constructable] to [Constructible]
12. Timer fields: leave unserialized, add [AfterDeserialization] method

Quick Mapping

RunUO	ModernUO
public class Foo : Item	[SerializationGenerator(N, false)] public partial class Foo : Item (N = old version + 1)
private int m_X + manual Serialize	[SerializableField(0)] private int _x
[CommandProperty(GM)] on property	[SerializedCommandProperty(GM)] on field
Foo(Serial serial) : base(serial)	DELETE
Serialize(GenericWriter)	DELETE -- auto-generated
Deserialize(GenericReader)	Convert to private void Deserialize(IGenericReader reader, int version) for old saves
Custom setter with InvalidateProperties()	[InvalidateProperties] attribute
Custom setter logic	[SerializableProperty(N)] with this.MarkDirty()
reader.ReadMobile()	reader.ReadEntity<Mobile>()
reader.ReadItem()	reader.ReadEntity<Item>()

Anti-Patterns

• Missing partial keyword -> build error
• Serializing TimerExecutionToken -> build error
• Missing this.MarkDirty() in [SerializableProperty] setter -> changes not saved
• Wrong field prefix (m_ instead of _)

See Also

• dev-docs/runuo-migration-docs/02-serialization.md -- detailed migration reference with before/after
• dev-docs/serialization.md -- complete ModernUO serialization system
• dev-docs/claude-skills/modernuo-serialization.md -- ModernUO serialization skill (patterns, attributes, examples)