## Summary
- **Add a self-referencing `InterpolationHandler` to `ValueStringBuilder`** that writes directly into the builder's buffer — zero intermediate allocation, works with `stackalloc`-backed builders
- **Replace all `System.Text.StringBuilder` usage** across the codebase with `ValueStringBuilder`
- **Convert `ValueStringBuilder.Create()` to `stackalloc`** at 10 sites where output length is provably bounded
- **Convert manual `Dispose()` to `using var`** where possible, and hoist loop-scoped builders outside loops with `Reset()`
- **Convert verbose `Append()` chains to `Append($"...")`** interpolation for readability
- **Add comprehensive documentation** for string handling patterns
## InterpolationHandler Design
`ValueStringBuilder` is a `ref struct`, which creates challenges for C#'s interpolated string handler pattern:
- **`ref` fields to ref structs are not allowed** (CS9050)
- **`[InterpolatedStringHandlerArgument("")]` passes struct receivers by value**, not by ref
- **`ISelfInterpolatedStringHandler` requires boxing** ref structs into interface fields
**Solution: Copy-and-reconcile pattern.** The handler receives a value copy of the builder. The copy shares the same underlying `char` buffer (`Span` points to the same `stackalloc`/pooled memory), so writes go to the original buffer. `Append()` reconciles by `this = handler._builder`, updating `_length` and any buffer references changed by `Grow()`.
This is safe because:
- The game loop is single-threaded — no concurrent access between handler construction and reconciliation
- If `Grow()` occurs in the copy, the original's stale buffer isn't accessed until `Append()` replaces it
- `Dispose()` correctly returns the reconciled buffer to the pool
## Changes by Category
### ValueStringBuilder (`Projects/Server/Buffers/ValueStringBuilder.cs`)
- Added nested `InterpolationHandler` ref struct with copy-and-reconcile pattern
- Added `Append([InterpolatedStringHandlerArgument("")] scoped ref InterpolationHandler)` method
- Removed `RawInterpolatedStringHandler` overloads (new handler replaces them)
- All `AppendFormatted` overloads delegate to existing `Append` methods (no code duplication)
- Alignment support via direct private field access (nested type privilege)
### StringBuilder → ValueStringBuilder (15 files)
Replaced all `new StringBuilder()` with `ValueStringBuilder.Create()` or `stackalloc`:
- ConPVP games: KingOfTheHill, DoubleDom, CTF, BombingRun, TourneyMatch
- ConPVP infrastructure: Tournament, Participant, TourneyParticipant
- ConPVP gumps: ArenaGump, TournamentBracketGump, AcceptTeamGump, ConfirmSignupGump
- Commands: Handlers, Logging, Add
- Other: TownCrier, SpeechLogGump, TestCenter
Key patterns:
- `sb = new StringBuilder()` reassignment → `sb.Reset()`
- `sb.AppendFormat("{0:N0}", value)` → `sb.Append($"{value:N0}")`
- `sb.Append(x).Append(y)` chains → separate statements (VSB returns void)
### Create() → stackalloc (10 files)
Converted heap-allocated builders to stackalloc where output is bounded:
- ClientVersion (32), MapSelection (160), HouseRaffleStone (48)
- HolySense (96), UnholySense (96), ClientVerification (192)
- AcceptTeamGump (64), ConfirmSignupGump (64)
- BaseWeapon (160), BaseArmor (128)
### Loop optimizations (2 files)
Hoisted `ValueStringBuilder` creation outside loops with `Reset()` per iteration:
- TourneyMatch.cs: `using var` inside for loop → stackalloc before loop
- ArenaGump.cs: `Create()` + `Dispose()` per iteration → stackalloc before loop
### Append chain → interpolation (5 files)
Converted multi-line `Append()` chains to `Append($"...")`:
- BountyMessage.cs: title switch (6 cases), paragraph (15→1 Append), description lines, closing
- AcceptTeamGump, ConfirmSignupGump, TournamentBracketGump: tournament type strings
- AdminGump: comment/tag formatting in loops
### Documentation
- `dev-docs/string-handling.md`: Full reference — construction, interpolation, disposal, decision guide
- `dev-docs/claude-skills/modernuo-string-handling.md`: Claude skill with quick reference
- `CLAUDE.md`: Added rule 17 (no StringBuilder), dev-docs table entry, skills table entry
- `dev-docs/code-standards.md`: Updated memory management section
## Test Plan
- [x] `dotnet build` — 0 errors, 0 warnings
- [x] `dotnet test` — 940/940 tests pass
- [x] 28 ValueStringBuilder tests covering all reconciliation scenarios:
- Stackalloc no-grow, stackalloc with grow (→pool transition)
- Heap no-grow, heap with grow, heap double grow
- Pre-existing content with and without grow
- Sequential multiple `Append($"...")` calls
- Mixed plain + interpolated Append
- Empty interpolation, literal-only, format specifiers
- Null string holes, ISpanFormattable types
- Dispose after stackalloc→pool grow
## Summary
Implements T2A-accurate mechanics for the three defensive spells based on UO98 demo scripts. Pre-UOR (`!Core.UOR`) triggers the new behavior; UOR and AOS paths are unchanged.
- **Reactive Armor**: percentage-based melee damage reflection (10-35% based on target Magery), targeted, timed (25-75s). Guards exempt, ranged attacks beyond 1 tile unaffected. Reflected damage is sourceless.
- **Protection**: temporary AC bonus (casterMagery/10, 1-10 AR) via VirtualArmorMod, targeted, timed (12-120s). Shared table with Arch Protection — only one protection buff per mobile.
- **Magic Reflect**: single-use spell reflection using MagicDamageAbsorb as a flag. No timer, no DefensiveSpell lock. Consumed on first reflected spell.
- **Arch Protection**: T2A path applies Protection via shared table with area sound (0x1F7 vs 0x1ED).
- No DefensiveSpell mutual exclusion for T2A — all three spells operate independently.
## Test plan
- [x] Set expansion to T2A
- [x] Cast Reactive Armor on self → verify particles (0x376A) and sound (0x1F2)
- [x] Get hit in melee → verify attacker takes reflected damage with spark effect and sound
- [x] Get hit by ranged weapon from > 1 tile → verify no reflection
- [x] Wait for RA to expire → verify effect ends silently
- [x] Cast RA on target that already has it → verify "This spell is already in effect"
- [x] Cast Protection on another player → verify particles (0x375A) and sound (0x1ED)
- [x] Check target's AR → verify it increased by casterMagery/10
- [x] Wait for Protection to expire → verify AR returns to normal
- [x] Cast Protection on self, then cast Protection on another player → verify both succeed
- [x] Cast Arch Protection on ground near allies → verify each gets AR bonus with sound 0x1F7
- [x] Cast Arch Protection near a target already protected → verify that target is skipped
- [x] Cast Magic Reflect on self → verify particles (0x375A) and sound (0x1E9)
- [x] Have an enemy cast a harmful spell at you → verify spell reflects back, effect consumed
- [x] Cast Magic Reflect again → verify it can be recast after consumption
- [x] Cast Magic Reflect when already active → verify "This spell is already in effect"
- [x] Verify all three spells can be active simultaneously on the same mobile
- [x] Switch expansion to UOR → verify existing UOR behavior unchanged
- [x] Switch expansion to AOS → verify existing AOS behavior unchanged
## Summary
- Adds `public virtual bool Murderer => Kills >= 5` property to `Mobile`, replacing ~30 scattered `Kills >= 5` / `Kills < 5` magic-number checks across the codebase
- `BaseCreature` overrides `Murderer` to also return `true` when `AlwaysMurderer` is set
- Updates `Corpse` serialization to v15, storing `_murderer` as a `bool` field (migrated from `int Kills >= 5` in earlier versions)
### Summary
Updates all calls to container.EnumerateItems() to properly dispose of the underlying PooledRefQueue so that we are properly recycling pooled arrays.
Fix [add command failing with ambiguous type names + refactor for performance
### Problem
[add blight would fail with "No type with that name was found" because multiple types contain "blight" (e.g., Server.Items.Blight, Server.Ethics.Evil.Blight, Server.Items.BlightGrippedLongbow, Server.Items.QuiverOfBlight). The old code only succeeded when exactly one type matched the search regardless of constructability and inheriting Mobi les/Items.
### Solution
Exact match takes priority: If a type's name exactly equals the search string (case-insensitive), use it directly. Otherwise, show the AddGump with all partial matches.
- [add blight → Creates Blight (exact name match)
- [add bligh → Shows gump with Blight, BlightGrippedLongbow, etc.
### Refactoring
- CommandEventArgs context: Added GetContext<T>/SetContext<T> to pass resolved type through the command chain without method signature changes
- Removed TrySetupTarget duplication: Validation now happens only in ValidateArgs, eliminating redundant code paths
- Split type matching:
- ExactMatch(string) → Returns Type for exact name match (used by [add)
- MatchEmptyCtor(string) → Returns ConstructorInfo[] for gump display (empty-callable constructors only)
### Memory & Performance Improvements
| Optimization | Benefit |
|-------------------------------|----------------------------------------------------------------------------------------------|
| _mobileItemTypes cache | Filters Mobile/Item types once per assembly, reused on all subsequent searches |
| ReadOnlySpan<string> for args | Avoids string[] heap allocations when slicing arguments |
| ValueStringBuilder | Stack-allocated string building, avoids StringBuilder heap allocation |
| Single type resolution | Type resolved once in ValidateArgs, passed via context to Execute (was resolved 2-3x before) |
### Summary
This PR transitions the spawner system from a simple radius-based model to a flexible 3D boundary system.
### Core Changes
* **Replaced `HomeRange` with `SpawnBounds`**: Spawners now use a `Rectangle3D` to define spawn areas instead of a circular integer range.
* **Backward Compatibility**:
* The `HomeRange` property remains as a helper that generates square `SpawnBounds` centered on the spawner.
* Included a migration path (v10 to v11) that automatically converts old range data into new bounds during deserialization.
* **Dynamic Bounds Shifting**: If a spawner is moved, its `SpawnBounds` will automatically shift with it, provided the bounds are currently configured as a centered square.
* **New Spawn Logic**: Added `SpawnLocationIsHome` toggle. If enabled, spawned mobiles treat their exact spawn coordinates as their "Home" rather than the spawner's location.
### Implementation Details
* **Interface Updates**: Updated `ISpawner` to include `WalkingRange`, `SpawnBounds`, and `IsInSpawnBounds()`.
* **UI Enhancements**: The Spawner Controller Gump now displays "Custom" for complex bounds and allows copying of the new boundary properties between spawners.
* **Refactored Constructors**: Streamlined `BaseSpawner`, `ProximitySpawner`, and `RegionSpawner` constructors to support the new data types.
> [!IMPORTANT]
> **Developer Note**
> THIS IS A BREAKING CHANGE TO THE NEW API GUMP.
> Please give us feedback in [discord ](https://muo.gg/discord) if you have issues, need help, or have ideas for a better API change!
### Summary
* Adds support for size/style to dynamic/static builder.
* Drastically simplifies the dynamic/static builder api for AddHtml.
* Cleans up some legacy gump files.
### Summary
- Adds [Code Generated Events](https://github.com/modernuo/CodeGeneratedEvents)
- Removes EventSink.PlayerDeath
- Adds `PlayerDeathEvent` and `CreatureDeathEvent` using code generated events
> [!Important]
> **Developer Note**
> Use `[OnEvent(nameof(PlayerMobile.PlayerDeathEvent))]` instead of `EventSink.PlayerDeath` delegate
> Check this commit for examples of how to use this.
> [!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
- Fixes an issue that causes CUO to crash due to bad string caching in static gumps
- Fixes wrong/bad 16bit html gump hues.
- Moves `C16232` (16-bit to 32-bit) and `C32216` (32-bit to 16-bit) to Utility class for broader use.
TODO:
- Some gumps have different 32bit (for string content) vs 16bit (for localized content) strings. Does this matter?
### Summary
- Fixes `[AdvancedSearch` being accessible by players 😱
- Adds `[GenCommands` to generate the same commands html page on https://muo.gg/commands.
- Fixes `[helpinfo` so all commands properly show up!
> [!WARNING]
> ### Developer Warning:
> Commands must now be registered in the `Configure` bootup phase.
> If a command is not registered early enough, it may not be available to systems like [helpinfo
> that cache their information.
> [!NOTE]
> ### Developer Note:
> Various commands related to generating content have been changed to _Developer_ and above access level.
### Screenshots
<img width="673" alt="image" src="https://github.com/modernuo/ModernUO/assets/3953314/b105b5c9-5eb4-4ace-93ff-1bfb31e7132f">
<img width="547" alt="image" src="https://github.com/modernuo/ModernUO/assets/3953314/e97487e8-47a5-4aa7-89cc-9fe3deda584d">
### Summary
- Fixes issues with non-_ISerializable_ objects having bad serialization (Skill/Stat. Mods)
- Fixes issues with MarkDirty and namespaces: https://github.com/modernuo/SerializationGenerator/issues/29
- Fixes missing dirty tracking for some data structures.
- Fixes cascading MarkDirty for non-serializable types that have owners that are also non-serializable types.
### New Codegenned API
When a data structure (Array, List, Dictionary, HashSet, etc) is source generated for serialization, new methods are added which will handle dirty tracking. Use these instead of the built in methods for that data structure.
_All Data Structures_
```cs
public void Clear<PropertyName>();
```
_Lists and Sets_
```cs
public void AddTo<PropertyName>(V value);
public void RemoveFrom<PropertyName>(V value);
```
_Lists_
```cs
public void InsertInto<PropertyName>(int index, V value);
public void RemoveFrom<PropertyName>At(int index);
```
_Dictionaries_
```cs
public void AddTo<PropertyName>(T key, V value);
public void RemoveFrom<PropertyName>(T key);
public void ReplaceIn<PropertyName>(T key, V value);
```
Over time, they will be cleaned up and more variants added such as `bool RemoveFrom<PropertyName>(T key, out V value)`
### 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
TLDR - .NET Framework rounded TimeSpan (and some DateTime) methods to the nearest millisecond. This was actually _expected_ accidentally for parts of RunUO.
We are aiming to fix this and clean up some other bad assumptions.
Closes#1604
### Summary
Eliminates `IPooledEnumerable<NetState>` and `eable.Free()` from `Map` for clients. This drastically simplifies code that iterates in range, for example:
```cs
foreach (var m in m.GetClientsInRange(5))
{
}
```
The code above no longer requires an eable and calling `Free()`.
### 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()`.
### Summary
Container enumeration is in dire need of optimization. Thanks to @stefanomerotta for initiating this work with PR #1443. This PR handles a small part of what Stefan started. Also included are some bug fixes.
### Method Signatures
```cs
// Use with foreach without moving/deleting items
FindItemsByTypeEnumerator<T> FindItemsByType<T>(bool recurse = true, Predicate<T> predicate = null)
// Use with foreach when moving/deleting items
QueuedItemsEnumerator<T> EnumerateItemsByType<T>(bool recurse = true, Predicate<T> predicate = null)
// Use when iterating multiple times or queuing
PooledRefQueue<T> QueueItemsByType<T>(bool recurse = true, Predicate<T> predicate = null)
// Use when iterating multiples times or manipulating elements without traversing
PooledRefList<T> ListItemsByType<T>(bool recurse = true, Predicate<T> predicate = null)
```
* `FindItemsByType<T>` has changed from returning `List<T>` to `FindItemsByTypeEnumerator<T>` - This method is not safe to use in situations where an item may get consumed, deleted, or moved.
* `EnumerateItemsByType<T>` was added as a safe way to iterate and manipulate items.
* **Note**: EnumerateItemsByType will _completely traverse the container_ before iteration starts because it uses `QueueItemsByType` under the hood.
* `QueueItemsByType<T>` and `ListItemsByType<T>` was added to return a queue or list of items to iterate multiple times and manipulate the items. This isn't the most efficient since it uses a predicate and can result in 2 or 3 total iterations unnecessarily.
### Bug Fixes
- [X] Fishing had an error in the random check that may have caused slight bias.
* * Fix statmod naming mismatch: everything in code searches for "[Magic] {type} Offset" but stat reductions are being added as "[Magic] {type} Curse"
* Clarifies and cleans up curses
* Fixes blood oath
* * NobleSacrifice remove all curses in one go
* Dont need a method
* Fix extra parentheses
Co-authored-by: Kamron Batman <3953314+kamronbatman@users.noreply.github.com>
## 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.
### THIS IS A BREAKING CHANGE IF YOU ARE ALREADY USING CODEGEN. IF YOUR WORLD HAS ERRORS LOADING PLEASE CONTACT ME ON DISCORD. ORE MIGHT FAIL TO LOAD.
### Changes
* Fixes Components from addons not marking dirty
* Code gens BaseAddonContainer
* Code gens Ingots
* Fixes code gen deserialization for Ore
* Code gens dyetubs
* Code gens reagents
* Code gens tailor commodities
* Code gens fish
### Changes/Fixes:
* Adds timer pooling.
* Allows pool to be configurable in ModernUO.json
* Pool replenishes itself asynchronously if depleted.
* Fixes an issue with barkeeps and town criers
* Fixes an issue with incognito buff icons not being removed
* Fixes an issue with polymorph name mod not being removed
* Fixes several places where timers go on forever even after an object is deleted, keeping a reference (memory leak)
* Eliminates the timer for MiningCart altogether.
* Deletes `AcidSlime` since it is a duplicate of `PoolOfAcid`
* Fixes HonorableExecution and standardizes the code for other Bushido moves.
## Changes to the Timer API:
```cs
public class Timer
{
// Creates a timer that will be returned to the pool once execution stops.
public static void StartTimer(Action callback);
public static void StartTimer(TimeSpan delay, Action callback);
public static void StartTimer(TimeSpan delay, TimeSpan interval, Action callback);
public static void StartTimer(TimeSpan interval, int count, Action callback);
public static void StartTimer(TimeSpan delay, TimeSpan interval, int count, Action callback);
// Creates a timer and returns a token for more control. Requires manual cancellation in order for the timer to be returned to the pool.
// If the token is dereferenced, the timer will be dereferenced too. While not returning a timer to the pool is not considered hazardous, it does defeat the purpose of pooled timers.
public static void StartTimer(Action callback, out TimerExecutionToken token);
public static void StartTimer(TimeSpan delay, Action callback, out TimerExecutionToken token);
public static void StartTimer(TimeSpan delay, TimeSpan interval, Action callback, out TimerExecutionToken token);
public static void StartTimer(TimeSpan interval, int count, Action callback, out TimerExecutionToken token);
public static void StartTimer(TimeSpan delay, TimeSpan interval, int count, Action callback, out TimerExecutionToken token);
// If you aren't sure how to use the API above, or you don't care about performance, then you can use the old RunUO Timer.DelayCall
public static DelayCallTimer DelayCall(Action callback);
public static DelayCallTimer DelayCall(TimeSpan delay, Action callback);
public static DelayCallTimer DelayCall(TimeSpan delay, TimeSpan interval, Action callback);
public static DelayCallTimer DelayCall(TimeSpan interval, int count, Action callback);
public static DelayCallTimer DelayCall(TimeSpan delay, TimeSpan interval, int count, Action callback);
}
public struct TimerExecutionToken
{
public bool Running { get; }
public int Index { get; }
public int RemainingCount { get; }
public DateTime Next { get; }
}
```
## When to use `TimerExecutionToken`?
Use tokens when you want to gain the performance benefit of using a pooled timer, but you need one of the following:
* Access to the next time the timer will tick:`token.Next`
* Access to which interval, how many intervals there are, or how many are remaining: `token.Index`, `token.Count`, and `token.RemainingCount`
* Stop a timer manually.
* Determine if the timer is running: `timer.Running`
* See notes below about requirements for using tokens!
## Notes about using the TimerExecutionToken:
When you opt-in to receive a token, you must call `Cancel()` to return the timer. This can be done inside of the callback, or outside of the callback at any time.
If this is not called and your timer is an infinite interval, then you will create a potential memory leak, or null pointer exception in your callback.
If the timer ends and is stopped, but cancel is not called, then the timer will never return to the pool and stay referenced until the token is deleted or cancel is called. (Memory leak)
## Is this thread safe?
No. The ModernUO timer system is not thread safe at all. If you require a thread safe timer system, contact me and I'll help adapt this system. Keep in mind that there is a massive performance hit to make this thread safe when there are literally no use cases for it.
If you need to synchronize execution, meaning you want to execute code from another thread on the core thread. Let's say you have a discord bot that is pushing commands to the game server. Then use `EventLoopContext.Post(SendOrPostCallback callback, object state);`.
