## Why
Delta world saves (only changed entities re-serialized during the freeze) need two things from content: `Serialize` must be pure, and an unchanged entity must produce identical bytes on every save. An audit of the tree found the places that break this today. This PR fixes them and adds a diagnostic that measures byte stability in a running world over real time. No wire format changes, no version bumps.
## What
- **Guild**: `Serialize` ran the daily guildmaster recalculation (dictionary-order tie breaks, random picks, mutates another entity), war expiry, and the alliance leadership check on every save. That work now runs from `GuildMaintenanceTimer` (the former `WarTimer`, now started for both guild systems; the war and alliance checks are no-ops without the new guild system).
- **BaseHouse**: the `DecayLevel` getter wrote `LastRefreshed` and advanced the dynamic decay stage on every read, so any undecayable house changed its persisted bytes whenever a sign, gump, or `[Props` looked at it. It is now a pure read; `UpdateDecay()` on the decay tick advances the stage and refreshes a house that leaves the undecayable state.
- **Locked-down container contents decay through `DecayScheduler`** instead of a sweep inside `BaseHouse.Serialize`. `Item.CanDecay` now accepts a parent container whose new `Container.ContentsDecay` is true (locked down and not secure) when the content item is not itself locked down or secured; the `IsLockedDown`/`IsSecure` setters re-evaluate a container and its direct contents; `OnDecay` resolves the region from the world location. `BaseBoard`, `Aquarium` and `FishBowl` override `ContentsDecay` to false, matching the exclusions of the old sweep. Items already inside such containers are picked up at load, where every item re-evaluates its registration. The per-save O(all locked-down items) walk is gone; the work is now event driven.
- **BraceletOfBinding**: the `Bound` getter nulled its backing field for a deleted target; it now returns null for a missing or deleted target without writing.
- **`[SaveStability [delaySeconds=60] [sampleStride=1]`** (Administrator): hashes the serialized bytes of every entity in every registered entity persistence (`Persistence.EntityPersistences`, new), waits the delay in real time, hashes again, and reports per type how many records changed. Both passes are chunked under a 20 ms per-tick budget. Serializing twice inside one tick cannot see drift derived from `Core.Now`, which is frozen within a tick; the real-time wait is the point. On an idle shard the only legitimate churn is NPC movement and regeneration, so a static type with a high changed fraction is a serialization bug. `[SaveStability cancel` stops a run.
Engine additions: `Container.ContentsDecay` / `UpdateContentsDecayRegistration()`, the `CanDecay`/`OnDecay` change above, and diagnostic-facing `IGenericEntityPersistence.Name`, `EntityCount`, `EnumerateEntities()`, and `Persistence.EntityPersistences`.
## Behaviour notes
- Fealty recalculation now happens on the minute timer for both guild systems instead of at save time.
- A house that becomes decayable is refreshed on its next decay tick rather than at the exact moment of transition (at most one minute later).
- Contents of locked-down containers now decay on their own schedule (same `LastMoved + DecayTime` rule) instead of at the next world save after becoming due.
## Testing
- New tests: `GuildSerializePurityTests`, `HouseDecayPurityTests`, `SaveStabilityTests` (stable entities hash identically after the clock advances; a clock-stamped record is reported by type only after the clock advances; the snapshot covers Items, Mobiles and Guilds).
- `LockedDownContainerDecayTests` (Server.Tests): registration on drop, lock/secure/release transitions, excluded containers, nested containers, and decay on schedule through the scheduler.
- Full suites: Server.Tests 855 passed, UOContent.Tests 765 passed.
## Problem
Houses and boats (multis) were pathed correctly only by **delegation to the slow path**: `StepCache.TryGetMask` returns `Fallthrough_Multi` for any multi-covered cell, and `GetSuccessors` ran `CheckMovement` **8× per cell** (each re-resolving the tile stack via `GetStaticAndMultiTiles`) — a sustained per-step cost near every house/boat. There was also no automated test pinning multi pathfinding.
This branch is the full multi-pathfinding effort in phases on one branch.
## Phase 1 — characterization tests (the oracle)
Implementation-agnostic invariants: a cache-on≡cache-off whole-path invariant, a per-cell sweep vs `CheckMovement` over footprint+halo (incl. destination Z), hand-verified routing (around walls, demolish-reopens, foundation-redesign-honored), classic-house / foundation / boat fixtures, non-vacuity guards. These gate every later phase byte-for-byte.
## Phase 2 — live single-pass synthesizer
`StepProbe.ComputeMultiMaskAt` synthesizes a covered cell's full 8-direction `StepMask` in one pass (the existing surface/step logic over `GetStaticAndMultiTiles` instead of 8× `CheckMovement`). `GetSuccessors` routes `Fallthrough_Multi` cells through it. No new cache, no `.swb` change. **~1.5×**, zero added allocations.
## Phase 3 / 3.1 — warm per-`multiID` interior cache (airtight)
`MultiMaskCache` caches each fixed multi's local-frame `StepMask` for **interior** cells (cell + all 8 neighbours covered → terrain-neighbour-free → position-invariant), keyed by `multiID & 0x3FFF`, built lazily from the MCL. Interior cells become ~20 ns lookups.
The cache is gated on a **per-instance footprint-clean flag** (`BaseMulti.PathInteriorCacheState`): an instance whose whole footprint terrain is below its floor (`maxTerrain < minFloor`) serves from the cache; a **dirty** instance (terrain intrudes — a contrived/GM placement) **degrades to live-synth, never a wrong mask**. This closes a cross-instance soundness gap (the cached mask depends on neighbour terrain too) found in a holistic review. The gate resets whenever the footprint's world-terrain relationship can change — **location, map, or ItemID** (a boat's heading swaps the MCL).
**Boats are cached too.** Their per-`multiID` deck masks are movement-invariant (built once per heading), so a sailing boat never rebuilds them; only the cheap clean-flag rescan repeats per move (and only when pathed near). Narrow existing boats have little interior; wide galleons (`multi.mul`) would gain Castle-class. `HouseFoundation` (per-instance runtime `DesignState`) is the one type that stays on the live path.
## Verification
- `UOContent.Tests` **454/454**, `Server.Tests` **708/708**, 0 failures.
- The Phase-1 oracle (`MultiPathInvariantTests`, cache-on ≡ cache-off) stays **byte-identical** with the synthesizer + interior cache active.
- Tests pin: footprint-cleanliness (clean vs sunk), dirty/cluttered placement degrades to live-synth while still pathing, clean placement serves, and the gate resets on move/ItemID change.
## Performance (modernuo/ModernUO-Benchmarks#8, full-fixture)
Houses at **Green Acres** (flat staff region → clean footprints, the legit-placement case):
| Route | Slow path | Phase 3.1 (interior cache) | Speedup |
|-------|----------:|---------------------------:|--------:|
| `around_a` (29 steps) | 238.3 µs | **49.1 µs** | **4.85×** |
| `around_b` (29 steps) | 224.3 µs | **49.5 µs** | **4.53×** |
~130 of ~167 multi cells/route serve from the cache (~20 ns) vs 37 live-synth. Per-cell, the slow path's 8× `CheckMovement` grows with multi complexity (GuildHouse ~857 ns → Castle ~1,194 ns), the synthesizer is a flat ~780 ns, and the cache serve is ~20 ns — so big/tall multis (and wide galleons) gain most. Identical allocations throughout.
## Summary
- Converts `HouseGumpAOS` from legacy `Gump` to `DynamicGump` with a private constructor and the static `DisplayTo` entry-point pattern.
- `AddPageButton`, `AddButtonLabeled`, and `AddList` helpers now write directly to the `DynamicGumpBuilder` via `ref` parameters.
- All internal re-display calls and the `HouseSign` / `ConfirmResizeHouseGump` callers route through `HouseGumpAOS.DisplayTo`.
- Field naming updated to underscore-prefix convention (`_house`, `_page`, `_from`, `_list`, `_hangerNumbers`, `_foundationNumbers`, `_postNumbers`, `_houseSigns`).
## Summary
- Converts the legacy pre-AOS `HouseGump` to `DynamicGump` with a private constructor and the static `DisplayTo` entry-point pattern.
- `HouseListGump` and `HouseRemoveGump` now route back through `HouseGump.DisplayTo` instead of constructing the gump directly.
- Updates the `HouseSign` caller accordingly.
### Summary
Updates all calls to container.EnumerateItems() to properly dispose of the underlying PooledRefQueue so that we are properly recycling pooled arrays.
### Summary
Changes component verification so the order is now housing.bin, then txt files in client, then txt files in Data/Components folder on the server.
> [!Important]
> **Developer Note**
> This code change will **completely move gumps out of the core**
### Summary
- Adds `GetGumps()` convenience which exposes methods to Find/Close/Send multiple gumps. This helper is a performance improvement by eliminating the Dictionary<Player, List> lookup for gumps.
## 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.*
> [!Warning]
> Users on Linux/OSX will need to follow the Readme
> and make sure `libdeflate` is properly installed
> [!Note]
> **Developer Note**
> The API for compression has changed. Use `Deflate.Standard` for the same functionality.
### Summary
* Replaces Zlib with LibDeflate for a 50% performance improvement!
* Adds MacOS 14 to properly test Arm64
### Summary
* Adds `StaticNoticeGump<T>` and `StaticWarningGump<T>`
* Converts NoticeGump/WarningGump to use `DynamicGump`
* Changes various uses of notice gump and warning gump to their static counterpart.
### Summary
* Fixes syntax compile error when THREADGUARD is enabled.
* Removes `int packetLength` from incoming packet handles since they aren't needed.
### Developer Notes
Incoming packet handler `SpanReader` is now properly scoped to that packet by length.
### Summary
* Refactors getting static/multi tiles to not use allocations.
* `TileList` is now only used during bootstrapping and uses rented buffers to eliminate extra allocations.
* Replaces `StaticTile[] GetStaticTiles` with:
```cs
Map.StaticTileEnumerable GetStaticTiles(int x, int y);
Map.StaticTileEnumerable GetStaticAndMultiTiles(int x, int y);
Map.StaticTileEnumerable GetMultiTiles(int x, int y);
```
* Removes `Synchronized` and `lock` from TileMatrix. It is no longer considered a multi-thread safe system.
### Summary
- Works around a sneaky edge case bug in the JIT with stackalloc where sometimes the buffer is not zero'd.
- Fixes SendDisplayBoatHS
- Fixes sending health bars in the `SendEverything()` logic.
- Fixes a bug in sizing for some string helper functions.
### Developer Note
We are enabled `SkipLocalsInit` - do not rely on `stackalloc` to be zero'd. To zero the buffer, use `span.Clear();`
Closes#1606
### Summary
Eliminates `IPooledEnumerable<BaseMulti>` and `eable.Free()` from `Map` for multis. This drastically simplifies code that iterates in range, for example:
```cs
foreach (var m in m.GetMultisInRange(5))
{
}
```
The code above no longer requires an eable and calling `Free()`.
### Bug Fixes
- [X] Fixes an issue with searching through nested empty containers.
## BREAKING CHANGE
- Deletes `map.GetObjectsInRange` and `map.GetObejctsInBounds`
### Notes
Developers are expected to enumerate mobiles and items separately now using `map.GetMobilesInRange` and `map.GetItemsInRange`. This helps keep the code streamlined so we don't have to maintain multiple copies of ref struct enumerators that do the same thing.
### Fixes
- [X] Fixes bug with planks closing
- [X] Fixes issue with iterating items/mobiles from a null map
### Summary
Eliminates `IPooledEnumerable<T>` and `eable.Free()` from `Map` for mobiles. This drastically simplifies code that iterates in range, for example:
```cs
foreach (var m in m.GetMobilesInRange(5))
{
}
```
The code above no longer requires an eable and calling `Free()`.
- [X] Fixed several locations where an NPC that was damaged would cause a server crash.
- [X] Removed an unnecessary allocation in guard fake calls (NPCs calling guards on you)
- [X] Fixes damage precision loss in Poison Strike Spell
- [X] BogThing no longer attempts to "search" for boglings to eat when it is at full health
### Summary
Modifying a ValueLinkList using one of the methods will bump the "version". This field is used by iterators (foreach loops) to determine if the link list was modified while iterating. The sector.Items (and in the future other lists), will no longer be safe to modify while iterating. The server will _CRASH_ if the ValueLinkList is modified.
Thanks to @stefanomerotta for help!
### Screenshots
<img width="588" alt="image" src="https://github.com/modernuo/ModernUO/assets/3953314/83ee0b6e-ff4f-4768-9e29-84456e04b1ec">
### Summary
Eliminates `IPooledEnumerable<T>` and `eable.Free()` from `Map` for items. This drastically simplifies code that iterates in range, for example:
```cs
foreach (var item in m.GetItemsInRange(5))
{
}
```
The code above no longer requires an eable and calling `Free()`.
