## 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
### 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.*
### Summary
- Fixes the name `Vegies` to `Veggies`
- Adds feeding leather to goats
- Adds metal for Lava Lizards
- Fixes Bone Helm being classified as plate instead of bone.
- Fixes wooden shields not classified as wood.
### Note
On OSI, the preferred foods on the animal lore gump doesn't contain all possible favorite food categories. Furthermore, the one listed is not necessarily always the "first" in the list of possible categories. We aren't going to try and fix that since it isn't important.
## Changes
* Improves type hashing by introducing xxHash3 (64bit)
* Removes individual `tdb` files in favor of a single `SerializedTypes.db` file. This file is only used to identify a type that is being deserialized, which doesn't exist.
* Adds duplicate type alias detection
* Adds `AssemblyHandler.FindTypeByHash`
View changed files whitespaces: https://github.com/modernuo/ModernUO/pull/1172/files?diff=split&w=1
## SerializedTypes.db
The serialized types file is used to get back the original name of a type in case it no longer exists in code. This can easily be necessary if a class is renamed in code and no `TypeAlias` is provided.
### Format
byte[4] - version
byte[4] - count
--array--
byte[8] - xxHash
byte[1] - flag, 0 - null, 1 - not null
byte[n] - Full class name in UTF8
### Example
<img width="472" alt="SerializedTypes_Example" src="https://user-images.githubusercontent.com/3953314/195255429-31d24293-6bd1-419e-811b-07874dd0f78d.png">
## Benchmarks
Serialized 500 Type fields. The 8192bytes comes from the _ConcurrentQueue_ that would later be used for SerializedTypes.
Note that the queue is never cleared, so it's size grew considerably.
```cs
| Method | Mean | Error | StdDev | Allocated |
|--------------------- |---------:|---------:|---------:|----------:|
| BenchmarkXXHash | 18.44 us | 0.278 us | 0.260 us | 8192 B |
| BenchmarkTypeStrings | 25.09 us | 0.292 us | 0.259 us | - |
```
TODO:
* Add support in the Serialization Generator for `ReadType()` and `Write(Type)`
* Remove `SetTypeRef` from Serialization Generator
* Adds `SerializationProperty` - This will generate the private variable for serialization. Also provides an option `useField` to specify your own. Example:
```cs
[SerializationProperty(0, useField: nameof(_resource)]
```
## 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.
* Now reads Prof.txt to get the professions
* The templated professions are based on profession `TrueName`
* Adds missing starting equipment
* Implements gargish starting equipment
* Consolidates some of the code
* Moves TC stuff to the TC file.
* Fixes some starting equipment that was wrong.
Note:
* Implementing the original T2A professions is possible on the client side, but requires moving the old clilocs to the current clilocs file. In the current file the entries are blank.
* Using the original LBR professions (they match AOS but without necromancy/chivalry) is kind of confusing because the profession indexes are ripped out of the UOTD/UOR ones and have non-sequential indexes. This will probably cause confusion and people will get no templated items when they select the wrong profession.
* Adds `RaceFlag` to the `Race` object. This is `1 << RaceIndex`
* Replaces `RequiredRace` with `RequiredRaces` for items.
* Adds convenience flags for `RequiredRaces`
```cs
public const int AllowAllRaces = 0x7; // Race.Human.RaceFlag | Race.Elf.RaceFlag | Race.Gargoyle.RaceFlag
public const int AllowHumanOrElves = 0x3; // Race.Human.RaceFlag | Race.Elf.RaceFlag
public const int AllowElvesOnly = 0x2; // Race.Elf.RaceFlag
public const int AllowGargoylesOnly = 0x4; // Race.Gargoyle.RaceFlag
```
* Example usage on an item:
```cs
public override int RequiredRaces => Race.AllowHumanOrElves;
```
* Adds Wood and Stone armor material types
* Updates Woodland armor to Wood
* Adds proper messaging for race restrictions
* Adds gargoyle only for object properties
* Adds `CheckRace` functions for validating if a race or mobile can use the item:
```cs
bool CheckRace(Race race);
bool CheckRace(Mobile from, bool message = true);
```
* Adds save flag support (see `ElvenGlasses` for an example)
* Updates AOSAttributes so they are code genned
* Fixes embedded object support by adding an `IRawSerializable`
* Fixes various inconsistencies in serializing with codegen
- [X] Adds a property to `CommandProperty` to allow modifying `PropertyObject` where there is no property setter that is accessible.
- [X] Updates AosAttributes and friends
Example of how to make this work:
```cs
[CommandProperty(AccessLevel.GameMaster, canModify: true)]
public AosWeaponAttributes WeaponAttributes { get; private set; }
```
This fix is necessary because in release mode the optimizer will sometimes _entirely remove the setter_ because it knows it can do something that is more efficient _when the property setter is private_. RunUO got around this by declaring a public setter explicitly that _was empty_.
### Screenshot
<img width="313" alt="Screen Shot 2021-05-15 at 11 34 01 PM" src="https://user-images.githubusercontent.com/3953314/118387955-49293c00-b5d6-11eb-8f31-a3b5e31bd18b.png">
- [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
### API Breaking Change
Combined `AsciiMessage` and `UnicodeMessage` into a single function that takes two arguments, `bool ascii` and `string lang`. Lang can be null (or anything) if ascii is true.
- [X] Changes message packets
- [X] Cleans up some code
- [X] Uses benchmarks to determine if the spanwriter + copyfrom
