## Summary
Folds **113** hand-written `[SerializableProperty]` members into plain `[SerializableField]` declarations using the v4 setter hooks — value coercion/vetoes via `allowFieldChange`, post-change side effects via `fieldChanged` (whose `oldValue` parameter covers the old-house/old-sender unsubscribe patterns). Net **-450 lines** of setter boilerplate.
```cs
// before
[SerializableProperty(1)]
[CommandProperty(AccessLevel.GameMaster)]
public int Charges
{
get => _charges;
set
{
_charges = Math.Clamp(value, 0, MaxCharges);
InvalidateProperties();
this.MarkDirty();
}
}
// after
[SerializableField(1, allowFieldChange: nameof(AllowChargesChange))]
[SerializedCommandProperty(AccessLevel.GameMaster)]
[InvalidateProperties]
private int _charges;
private bool AllowChargesChange(ref int value)
{
value = Math.Clamp(value, 0, MaxCharges);
return true;
}
```
## How sites were selected
A classifier parsed all 204 `[SerializableProperty]` sites and converted only those matching strict shapes: getter is exactly `get => _field;`, the assignment comes first (after at most an equality guard), and relocated side effects contain no `return`, no `value` mutation, and no field re-assignment. Everything else was left alone deliberately:
- **~34 custom getters** (fallback defaults like `_x == -1 ? Default : _x`, self-healing refs) — no setter hook can express these.
- **~35 pre-assignment logic** (durability Unscale/Scale sandwiches, old-state captures like PotionKeg's pile weight).
- **virtual/override members, name-mismatched backing fields (`m_`), exotic semantics** (guards' `Focus` does work on *equal* assignment; `ChampionSpawn.Active` never assigns its field).
Five sites the classifier refused were converted by hand where the hooks fit cleanly: `ReceiverCrystal.Sender`, `PlayerVendor.House`, `PlayerBarkeeper.House` (old-value unsubscribe via `oldValue`), `BaseSuit.AccessLevel` (its existing virtual `OnAccessLevelChanged` already had the exact callback shape), and `DyeTub.DyedHue` (a true veto: `AllowDyedHueChange(ref int value) => _redyable`).
## Verification
- Build: **0 errors, 0 warnings**.
- **Schema regeneration produces zero Migrations changes** — the conversion is wire- and schema-neutral by construction (same orders, types, and property names), and CI's schema diff check enforces it.
- **835 + 708 tests green.**
## Behavioral notes (all strict improvements, called out for review)
- Generated setters skip everything when the incoming value equals the current one; a few converted setters previously re-ran side effects on equal assignment (redundant `Update()`-style refreshes).
- Generated setters always `MarkDirty()` on change; several converted setters never did (e.g. `DyeTub.DyedHue`, `MorphItem` ranges) — their changes only persisted if something else dirtied the entity. Those latent persistence bugs are fixed by construction.
## Changes
- [X] Adds OPL convenience methods
- `opl.Add(cliloc, value)` and `opl.Add(value)` - value as an integer or string works just like `opl.Add(cliloc, $"{value}")`
- `opl.AddLocalized(cliloc, clilocValue)` - works the same as `opl.Add(cliloc, $"#{clilocValue}");`
- [X] Simplifies basic `list.Add()` situations
- [X] Changes cliloc as an argument so it works with custom IPropertyList implementations (HTML)
- [X] Fixes plants so they support the old localization and new (changed in 7.0.12.0+)
- [X] Exposes more methods to override for Item to make creating custom OPL possible.
## Important Notes
* Using a ternary as an argument, like this `opl.Add(number, showType ? $"{type}\t{value}" : $"{value}");` _will not use the correct string interpolation_. This means if you use a custom PropertyList (for HTML or some other purpose), the property list won't be localized properly.
* All localization values must be interpolated, even if they are literal strings, or integers. Example: `opl.Add(number, $"{"Charges"}\t{m_Charges}");` is correct. Using the following: `$"Charges\t{m_Charges}"` will not work for custom PropertyList implementations!
## Breaking Changes (New API)
ObjectPropertyList supports the following API:
```cs
list.Add(500000);
list.Add(500001, stringArgument);
list.Add("Some text");
list.Add($"Some text with {argument}");
list.Add(500002, $"{arg1}\t{arg2}");
```
## Notes
1. All API uses that require a formatter like this:
```cs
list.Add(500002, "{0}\t{1}", arg1, arg2);
```
Should be changed to use string interpolation, for example:
```cs
list.Add(500002, $"{arg1}\t{arg2}");
```
2. The following paradigm should no longer be used:
```cs
list.Add(1061170, prop.ToString()); // strength requirement ~1_val~
```
The new string interpolation API will avoid having to convert the argument to a string before writing it to the packet. Instead use the following:
```cs
list.Add(1061170, $"{prop}"); // strength requirement ~1_val~
```
### Benchmarks
```cs
| Method | Mean | Error | StdDev | Gen 0 | Allocated |
|------------------------------- |---------:|--------:|--------:|-------:|----------:|
| BenchmarkOldOPL | 241.0 ns | 0.56 ns | 0.47 ns | 0.0105 | 88 B |
| BenchmarkStringInterpolatedOPL | 199.9 ns | 2.44 ns | 2.39 ns | - | - |
```
### Changes
- [X] Removes crash in STArray.Return when array is null.
- [X] Fixes NPE in OPL when entity is null. Serial in packet will be 0 when entity is null.
- [X] Fixes NPE in AosAttributes when Parent is null.
- [X] Changes OPL to use string interpolation.
- [X] Introduces `IPropertyList` to allow extending PropertyList for other uses.
- [X] Fixes an issue where a buffer smaller than 8 bytes would not double with enough space in some cases.
- [X] Fixes an issue with dupe copying the savebuffer reference (ugh).
- [X] Streamlines the IGenericWriter API to use better generics.
- [X] Streamlines the IGenericReader API to use better generics.
- [X] Forces `tidying` of a List/HashSet to be done externally since Writers/Readers should not have side effects.
- [X] Fixes an issue where Tidying a list didn't TrimExcess, causing memory leaks.
- [X] Reverted the meaning of `World.Running` to specifically refer to any world state post world loading.
- NOTE: Do not use this if you want to block on world saves. Instead use checks against `WorldState.Saving` states.
- [X] Fixes an issue with serializing negative DateTime deltas.
- [X] Fixes a potential issue with serializing non-UTC DateTime.
Bumps release version
