## The bug
`ObjectPropertyList.AddHash` folded each cliloc and a Marvin hash of each argument together with XOR, which is both commutative and self-inverse. Any value mixed in an even number of times cancelled outright, so two properties sharing one argument hashed identically no matter what that argument was:
```
_hash = 31659021
AddHash(1063752); AddHash(hash("10"))
AddHash(1063737); AddHash(hash("10")) // the argument cancels here
AddHash(1063740) // -> 32714560, for ANY argument
```
The 10% and 5% variants of the same item therefore produced the same revision. The client caches the tooltip by revision and only re-requests when it changes, so it kept rendering the stale percentage.
Same root cause, three more shapes:
| | old | new |
|---|---|---|
| Two properties sharing an argument | collides | distinct |
| Properties reordered | collides | distinct |
| Two properties trading arguments | collides | distinct |
| Argument-less property added twice | cancels to 0 | distinct |
## The fix
Hash the finished property block in `Terminate()` instead of accumulating per property. Those bytes — cliloc, length prefix and UTF-16 text, in emission order — are the exact content the client renders, so anything that changes the tooltip changes the hash. The length prefix also removes the concatenation ambiguity the old scheme had.
`AddHash` and both `string.GetHashCode` calls are gone.
## Why 26 bits, and why not 64
The client never recomputes the hash — it stores what we send in 0xD6 and compares it for equality against the 0xDC revision (`ObjectPropertiesListManager.IsRevisionEquals`). So the algorithm is ours to choose, but the width is not:
- Both packets carry a **4-byte** revision, so 64 bits is not available. A wider internal value would be worse than useless: the server would see a change and send a 0xDC whose truncated 32 bits are identical, and the client still wouldn't refresh.
- `Terminate` writes the bare hash into 0xD6 while `SendOPLInfo` writes `Hash` with bit 30 set. The client recovers one from the other by masking off `0x40000000`, which only holds while the hash stays below that bit. Hence 26 bits, unchanged from before.
- `Hash => 0x40000000 + _hash` keeps the revision non-zero; the client parks 0 as its "nothing cached" sentinel.
## Collision behaviour
Enumerated real small-OPL spaces and counted 26-bit collisions against the birthday expectation for a uniform hash:
| Scenario | block | n | collisions | expected |
|---|---|---|---|---|
| 1 cliloc, no arg (every cliloc 1.0M–3.2M) | 6 B | 2,200,000 | 35,591 | ~36,061 |
| 1 cliloc + numeric arg 0–199,999 | 8–12 B | 200,000 | 300 | ~298 |
| 2 clilocs, both with numeric args | 12–24 B | 202,500 | 288 | ~306 |
| 1 cliloc + 1-char arg | 8 B | 4,000,000 | 116,291 | ~119,209 |
Every case lands on the random-model line, and per-bit P(1) across all 26 bits is 0.4962–0.5024 — XXH3's short-input paths still avalanche fully, so a 6-byte block behaves like a uniform 26-bit draw. Masking the low 26 bits versus folding all 64 down was a wash (35,591 vs 35,558).
The metric that matters is narrower, since the client compares a revision only against the previous revision **for the same serial**: 2^-26 = 1.5e-8 per genuine tooltip change. Consecutive-value transitions (charges 50 -> 49) collided 0 times in 200,000.
Row 3 is the old scheme quantified: it collapsed 202,500 inputs into 100,954 distinct hashes, a 50% collision rate — systematic, not probabilistic.
One honest regression: in row 1 the old scheme had zero collisions, because for a single argument-less cliloc under 2^26 the hash was the identity function. An item whose whole tooltip is one argument-less cliloc changing to a different one goes from never colliding to 1.5e-8.
## Performance
Cheaper, not just correct — one xxHash3 pass replaces a Marvin hash per string property over those same bytes. A 12-property, 302-byte tooltip, steady state:
```
old (XOR + Marvin per property) 70.5 ns
xxHash3 (streaming, HashUtility) 27.0 ns
```
`XxHash3.HashToUInt64` one-shot is a further ~7ns faster and produces byte-identical output, but taking it would mean editing `HashUtility.ComputeHash64`, whose values are baked into save files via `AssemblyHandler.GetTypeHash`. Not worth it.
## Second commit: plant old-client property list
Found while tracing the `Hash` read sites. `PlantItem.OldClientPropertyList` called `InitializePropertyList` on every access instead of only when the list was null, and without a `Reset`. Every read appended another copy of every property to the same buffer. `SendOPLPacketTo` and `SendPropertiesTo` both go through the getter, so a pre-7.0.12 client looking at a plant grew the buffer without bound and moved the revision on reads alone.
Now builds once, matching `Item.PropertyList`. `InvalidateProperties` already `Reset`s before rebuilding.
## Testing
`Server.Tests` 869 passed, `UOContent.Tests` 779 passed.
New regression tests, each confirmed failing against the old code first:
- `RepeatedArgument_DoesNotCancelOut` — the reported case
- `PropertyOrder_ChangesHash`, `SwappedArguments_ChangeHash`, `DuplicateProperty_ChangesHash`
- `ShortNumericArguments_ConsecutiveValuesDiffer`, `SmallPropertyBlocks_StayWellDistributed` — short-input avalanche, bounded loosely enough to hold for any seed
- `Hash_StaysWithinTheRevisionMask`, `EmptyList_IsNonZeroAndDistinctFromPopulated` — wire constraints
- `PlantItemPropertyListTests.OldClientPropertyList_BuildsOnceAndIsStableAcrossReads`
## Why
Delta world saves re-serialize an entity only when it has been marked dirty. An audit of the generated classes found three ways serialized state changes without a mark; this PR closes the ones that do not need a new generator package.
## What
- **Custom `[SerializableProperty]` setters mark dirty.** Twelve hand-written setters assigned their backing field without `this.MarkDirty()`. `PlagueBeastLord.OpenedBy` was an auto-property carrying the attribute with no backing field at all; it is now a generated field with the same name, order and command-property exposure.
- **Generated sub-objects are linked to their owner.** Without a `[DirtyTrackingEntity]` member the generator emits setters that mark nothing. Eight entity-owned sub-objects now carry the link and receive the owner through the constructor the generator calls: `BOBFilter` (owner is `IEntity`: a `PlayerMobile` or a `BulkOrderBook`), `BOBLargeSubEntry`, `PuzzleChestSolution` and `PuzzleChestSolutionAndTime`, `TalismanAttribute` (the random factories now take the talisman), `VendorItem`, `PlayerBBMessage`, `RaffleEntry`, `ShardPollOption`. Migration schemas were regenerated with the pinned tool; the only change is the value rule argument becoming `DeserializationRequiresParent`.
- **BaseVendor uses the generator; restock amounts are no longer persisted.** The only state it wrote was which buy entries had grown restock amounts, packed by index into the live `SBInfos` tables. Restock is transient now and rebuilds on load; version 1 records are read and discarded through the legacy path. Every vendor subclass now serializes through a generated chain.
## Generator 4.1.0
This PR adopts SerializationGenerator 4.1.0 (modernuo/SerializationGenerator#55): SG3019/SG3020 diagnostics, `[VolatileSerializedState]`, `StopXxx()` timer helpers, and owner-constructor preference for sub-objects (so dictionary values are constructed with their owner; the 4.0.0 relink fallback is gone). `PlayerVendor.v3.json` gains `DeserializationRequiresParent` for its `VendorItem` values so the migration content struct constructs them with their vendor.
SG3019 is an error under `TreatWarningsAsErrors` and generator diagnostics ignore pragmas, so the five contexts that live in whole-file player-keyed persistences (`ChampionTitle`, `ChampionTitleContext`, `MurderContext`, `VirtueContext`, `JailRecord`) now carry a `[DirtyTrackingEntity]` link to their `PlayerMobile`, which is where they will live once those blobs move onto the player record. `JailSystem.EmptyRecord` keeps a null player (`[CanBeNull]`). `ChampionTitle` needs both a context and a player constructor because the generator resolves the rule against the containing type but emits the call with the parent field; a comment in the file records this.
## Wire format
Unchanged. No version bumps except `BaseVendor` 1 to 2 (which now writes nothing of its own). Schema diffs are rule-argument only (`DeserializationRequiresParent`).
## Testing
Server.Tests 848 passed, UOContent.Tests 759 passed.
## 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.
## Summary
Adopts ModernUO.Serialization 4.0.0 across the engine. Three commits, reviewable independently:
1. **Package + tool bump to 4.0.0** (`Server.csproj`, `UOContent.csproj`, `dotnet-tools.json`).
2. **Timers → `[DeserializeTimer]`** — the 8 drifting timers (BaseLight, TreasureMapChest, MarkContainer, FillableContainer, DeathRobe, DecayedCorpse, Corpse, BaseEscortable) now store their next tick as **anchored time**: server downtime no longer consumes the remaining delay, and idle-world saves are byte-stable. This changes their wire format, so each class bumps its serialization version with a `MigrateFrom` that replays the old delta-time read through the migration schema (the new `vN.json` files carry `@AnchoredTimer`; the old ones keep `@TimerDrift`, which the generator reads forever). The 2 wall-clock timers (Aquarium, FountainOfLife) keep their exact format via `wallClock: true` — no bump. Restart methods drop their `TimeSpan.MinValue` sentinel checks: v4 invokes them **only when a timer was actually running at save**.
3. **Linkage → field-side declarations** — 175 conversions across 25 files: `[SerializableFieldSaveFlag(order)]`/`[SerializableFieldDefault(order)]` become `[SaveFlag(nameof(...), nameof(...))]` on the field, and `[SerializableFieldChanged(order)]` becomes the `fieldChanged:` argument of `[SerializableField]`. **Wire-neutral: zero migration schemas changed.**
## Verification
- Solution builds with **0 errors, 0 warnings**; all three 4.0.0 packages verified indexed on nuget.org (no local feed needed).
- **835 + 708 tests green.**
- Generated output inspected: old-version content structs replay `ReadDeltaTime` (e.g. `V3Content.DecayTimerNext = reader.ReadDeltaTime()`), current versions write/read anchored time with the gated restart, and the wall-clock classes emit byte-identical `Write`/`ReadDateTime` framing.
- Schema tool run is committed (CI's `git diff --exit-code` schema check passes): exactly the 8 expected new `vN.json` files, nothing else touched.
- The conversion was scripted with a class-scoped resolver (order → same-class `[SerializableField(order)]`/`[SerializableProperty(order)]`); it planned 175/175 with zero ambiguities before applying.
## Notes
- New `MigrateFrom`s use the content structs' provided `XxxDelay` property, matching the pre-existing idiom in Corpse's and TreasureMapChest's older migrations.
- Follow-up candidate (separate PR, wire-neutral, any time): fold the ~150 eligible hand-written `[SerializableProperty]` setters (clamps, post-change side effects) down to `[SerializableField]` with `allowFieldChange`/`fieldChanged` hooks.
## Summary
Second PR in the player-facing legacy gump migration. Converts the four Plants system gumps:
- `MainPlantGump`, `ReproductionGump`, `EmptyTheBowlGump` → `DynamicGump`. Layout varies by plant status, growth stage, health, and pollination/resource availability — cannot use cached `StaticGump<T>`.
- `SetToDecorativeGump` → `StaticGump<SetToDecorativeGump>`. Pure confirmation dialog with no per-instance variation.
All four:
- `Singleton => true` (auto-replace previous plant gump on re-open instead of stacking)
- Constructor `private`; entry is static `DisplayTo(Mobile, PlantItem)` per the empty-gump rule (CLAUDE.md §13)
- `OnResponse` self-refresh paths converted from `from.SendGump(new XGump(_plant))` to `from.SendGump(this)` — saves an allocation on every help/info button click and on every "gather resources/seeds/pollen" action
- Helper draw methods take `ref DynamicGumpBuilder builder` instead of mutating instance state
- Renamed legacy `m_Plant` to `_plant` per CLAUDE.md §12
Updated external callers to use the new entry points:
- `PlantItem.OnDoubleClick` → `MainPlantGump.DisplayTo(from, this)`
- `PlantPourTarget.OnTargetFinish` → `MainPlantGump.DisplayTo(from, m_Plant)` (also drops the now-redundant legacy `singleton: true` flag — `Singleton` property handles it)
- `PollinateTarget.OnTargetFinish` → `ReproductionGump.DisplayTo(from, m_Plant)`
## Summary
- Removes allocation of a `List<ContextMenuEntry>` every time a context menu is created.
- Moves packet/context menu creation logic out of the core
- Fixes tame entry
## BREAKING CHANGE
> [!Important]
> **Developer Note**
> ```cs
> public virtual void GetContextMenuEntries(Mobile from, List<ContextMenuEntry> list)
> ```
> and similar functions changed to
> ```cs
> public virtual void GetContextMenuEntries(Mobile from, ref PooledRefList<ContextMenuEntry> list)
> ```
## Summary
### Changes
- Adds `[IgnoreDupe]` and `[SerializedIgnoreDupe]`
- Updates all _known_ classes that need the attribute. Some might be missing, please helps us find them!
- Adds `Item.Dupe()` command and encapsulates `CopyProperties` and `OnAfterDuped`. This is also overridable.
- Updates Dupe command to use the new logic.
- Fixes duping multiple kinds of objects that used to be outright broken.
### Bug Fixes
- Fixes issue with durability after duping
- Fixes issue with hue after duping
> [!Note]
> **Developer Note**
> Customizing how duping an item works now requires two steps:
> 1. Add `[IgnoreDupe]` or `[SerializedIgnoreDupe]` to the property/field
> 2. Add custom logic in an `OnAfterDuped` override
>
> When do you need to do this?
> *When the property being copied is not a primitive, and you need to manually deep-clone the contents of the property such as with Lists, Dictionaries, or sub classes.*
## 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.
