Highly Performant & Scalable Ultima Online Server Emulator
https://www.modernuo.com
c-sharpcsharpcsharp-coredotnetdotnet-coreemulatorgplgplv3mmommo-enginemmorpgmmorpg-serveronlinerpgrunuoserverservuoultimaultima-onlineuo
a2c232f4a8
## 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. |
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| LICENSE | ||
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| README.md | ||
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ModernUO 
Ultima Online Server Emulator for the modern era!
Requirements
Supported Operating Systems
Required Frameworks
All Operating Systems
Windows
Hardware
| Use | vCPU | RAM | Storage |
|---|---|---|---|
| Development / test | 2 dedicated | 2 GB | SSD |
| Small live shard (< 50 concurrent) | 4 dedicated | 4 GB | NVMe |
| Medium (50–200) | 4–8 | 8 GB | NVMe |
| Large (200+) | 8+, high clock | 16 GB+ | NVMe |
See dev-docs/server-requirements.md for more information.
Development
Supported IDEs
Getting Started
- Install prerequisite requirements
- Clone this repository (or download the latest):
git clone https://github.com/modernuo/ModernUO.git
- Open
ModernUO.slnto start developing
Building/Publishing
Interactive Mode (Recommended for new users)
Run ./publish.cmd (Windows) or ./publish.sh (Linux/macOS) with no arguments to launch the guided build tool. It will:
- Check prerequisites (.NET SDK, native libraries)
- Walk you through configuration and platform selection
- Build and publish the server to the
Distributiondirectory - Show deployment instructions for cross-compiled builds
Command Line
./publish.cmd [release|debug] [os] [arch]
os- Supported operating systemsarchx64- Intel/AMD 64-bitarm64- ARM 64-bit
Linux Prerequisites
Fedora, CentOS, RHEL, AlmaLinux, Rocky, etc
dnf upgrade --refresh -y
# RHEL-family distributions (CentOS Stream, AlmaLinux, Rocky, RHEL) need CRB and EPEL enabled.
# Fedora skips this block.
dnf install -y dnf-plugins-core
dnf config-manager --set-enabled crb
dnf install -y epel-release
# Prerequisites
dnf install -y findutils libicu libdeflate libargon2 tzdata
Ubuntu, Debian, etc
apt-get update -y
# The ICU runtime package carries the ABI version in its name (libicu74, libicu76, …) and has no
# stable alias, so match it by pattern rather than pinning a release-specific name.
apt-get install -y '^libicu[0-9]+$' libdeflate0 libargon2-1 tzdata
Only the runtime libraries are needed — the -dev/-devel packages are not. Run
./build-tool --check-prereqs to check the current machine and print the exact packages your
release needs.
zstd is not listed because ZstdNet bundles libzstd for every platform, and liburing is not
listed because IORingGroup issues io_uring syscalls directly.
If the shard's configured time zone is a legacy alias such as US/Eastern, Debian 12 and Ubuntu
24.04 also need tzdata-legacy. See Platform Prerequisites
for what each dependency is for and what breaks without it.
OSX Requirements
brew install icu4c libdeflate argon2
Running the Server
- Follow the publish instructions
- The
Distributiondirectory is portable — copy it to your production server for deployment - Run
ModernUO.exeordotnet ModernUO.dllfrom theDistributiondirectory - On first run, the server will prompt you to configure game data file locations
Troubleshooting / FAQ
- See FAQ
Want to sponsor?
Thank you for supporting us! You can find out how by visiting the sponsors page.
Collaborators
Thanks
- RunUO Team & Community
- Voxpire, the ServUO Team & Community
- Karasho, Jaedan and the ClassicUO Community
Development Tools & Plugins provided with ♥ by
Code Signing Policy
Free code signing provided by SignPath.io, certificate by SignPath Foundation.
This program will not transfer any information to other networked systems unless specifically requested by the user or the person installing or operating it
Teams & Roles
Approvers & Committers: Development Team