Repository layout

What's in the repository today: the files at its root, every project and what it depends on, the tests and the CI workflow. The server core itself isn't built yet; its design is on Server core design, and the codec, its first piece, is on Codec design.

The root

Build and repository files

File	Holds
global.json	The SDK pin, 10.0.400 with rollForward: latestPatch, and Microsoft Testing Platform as the test runner
Directory.Build.props	Nullable reference types on for every project; every warning an error; code-style rules run in the build; the analysis level pinned to 10-recommended
Directory.Build.targets	The hot-path switch: a project that sets <HotPath>true</HotPath> gets the banned-API list and the hot-path rules as errors
Directory.Packages.props	Every package version, pinned exactly (central package management)
nuget.config	nuget.org as the only package source, mapped for every package
.editorconfig	Formatting, style and naming rules, and every suppression with its reason
.gitattributes	* text=auto eol=crlf: text stored with LF, checked out with CRLF on every system
.git-blame-ignore-revs	Mechanical commits git blame skips: the line-ending normalization, the formatting pass and the renames
README.md, CONTRIBUTING.md, SECURITY.md, LICENSE	The front door, the contributor rules, how to report a security problem, the AGPL-3.0

Folders

Folder	Holds
Source/	Every project, and the solution Source/NexusTomorrow.slnx
Tests/	One test project per project under test
Tools/	One-off tools that work on the code itself; today the model converter, deleted when the codec step ends
Build/HotPath/	The hot-path ban list (BannedSymbols.txt) and the rules it raises to errors (HotPath.globalconfig)
.github/workflows/	The Tests workflow

Projects

Libraries

Every library targets net10.0, except the generator, which targets netstandard2.0 because the compiler loads it.

Project	Holds	References	Nullable
NexusTomorrow.Shared	Factories, configuration binding, the update timer, shared extensions		On
NexusTomorrow.Cryptography	SRP6 login maths, the packet cipher, password and random helpers		On
NexusTomorrow.IO	Readers for the client's area files; reader and writer for the server's map format, .nfmap		On
NexusTomorrow.Game.Static	The game's enums and flags, one folder per system		On
NexusTomorrow.GameTable	Typed loading of the client's game tables (.tbl) and text tables	Game.Static, Shared	On
NexusTomorrow.Network.Codec	The bit reader and writer, the declaration attributes, the layout types, and the client facts table. Hot path		On
NexusTomorrow.Network.Codec.Generator	The source generator that writes each declared type's reader, writer and layout, and its diagnostics NTC001 to NTC013		On
NexusTomorrow.Network	The old bit-level reader and writer, message framing, the opcode list, and the [WireMessage] attribute beside it	Cryptography, Network.Codec, Shared	On
NexusTomorrow.Network.Sts	Message models for the STS login protocol, in XML		On
NexusTomorrow.Network.Auth	Message declarations for the auth server; the generated reader and writer are their only code	Game.Static, Network; the generator	Off
NexusTomorrow.Network.World	Message declarations for the world server; the generated reader and writer are their only code	Game.Static, Network; the generator	Off

The two projects with nullable reference types off are the ones the codec's conversion replaces; they're converted as part of it. Every project builds with every warning as an error; those two also switch their analysers off until then. Network, Network.Auth and Network.World run the generator, which writes each model's reader, writer and size, and one WireMessages registry per assembly with a factory per direction keyed by opcode. The old bit reader and writer still sit in Network until stage 3 deletes them; only the legacy snapshot uses them now.

Tools

Project	Does	References
NexusTomorrow.MapGenerator	Extracts the game tables and localization files from your client, and generates .nfmap map files from its area files	GameTable, IO, Shared
NexusTomorrow.ClientConnector	Starts your client with a server's address on its command line. Windows only	Shared
NexusTomorrow.ModelConverter, in Tools/	Converts the old message models into codec declarations, in place, and reports every type it leaves alone. One-off	Game.Static, Network

How to run the first two is in the repository's README.md. Their output is built from your client and never goes in the repository. The converter reads only our own source.

Packages

Package	Used by
Microsoft.Extensions.* (configuration, dependency injection, logging, options)	Shared, Network, GameTable, MapGenerator, the tests
Microsoft.CodeAnalysis.CSharp, Microsoft.CodeAnalysis.Analyzers	The generator and its tests; the converter and its tests
Microsoft.CodeAnalysis.BannedApiAnalyzers	Every hot-path project, added by Directory.Build.targets
NLog	Shared
Newtonsoft.Json	GameTable, ClientConnector
CommandLineParser	MapGenerator
Nexus.Archive	MapGenerator, to read the client's archives
xunit.v3.mtp-v2, Microsoft.Testing.Extensions.TrxReport	The tests

Tests

Test projects

Project	Tests
NexusTomorrow.Network.Codec.Tests	The bit reader and writer against hand-derived bytes and against the old reader and writer; strings and packed floats; generated code on test messages of every member shape; the facts check over every message Network, Network.Auth and Network.World declare, with each disagreement pinned
NexusTomorrow.Network.Codec.Generator.Tests	Every diagnostic, and the source the generator emits
NexusTomorrow.ModelConverter.Tests	Each conversion pattern, on models compiled against the real old reader and writer
NexusTomorrow.Network.Equivalence.Tests	That every converted type writes and reads the same bytes as its old twin in the legacy snapshot, and that the harness catches the mistakes it's built to catch. Temporary, deleted with the snapshot
NexusTomorrow.Cryptography.Tests	The SRP6 session key is always 64 bytes
NexusTomorrow.GameTable.Tests	A missing or empty GameTablePath fails options validation, and a bound one passes
NexusTomorrow.ClientConnector.Tests	Reading the configuration throws, naming the key, when the host name or language is missing or empty, and returns both when they're set

268 tests in all, in seven xUnit v3 test applications on Microsoft Testing Platform: 146 in the codec's, 64 in the generator's, 30 in the equivalence harness's, 21 in the converter's, and 7 in the other three. One of the equivalence tests covers every converted type.

The legacy snapshot

Tests/NexusTomorrow.Network.Legacy holds no tests. It's an unchanged copy of the old message models from Network.World, Network.Auth and Network, compiled against the old reader and writer, so the conversion can be proven to produce the same bytes as the code it replaces. It's temporary: the codec's third stage deletes it along with the old primitives.

The workflow

.github/workflows/test.yml, named Tests:

Step	Does
Trigger	workflow_dispatch only, with an optional args input passed to the test applications
Runner	ubuntu-24.04
Permissions	contents: read
Checkout	Full history, so the commit check can see every commit since main; the token isn't kept in the checkout
Commit messages	Every commit in origin/main..HEAD: a blank second line, a headline of 72 characters or fewer, no full stop at its end
Em dashes	Fails on any em dash in a .cs or .md file, and lists where
Set up .NET	Installs the SDK global.json asks for: the latest 10.0.4xx patch
Restore, build	Against Source/NexusTomorrow.slnx, in Debug
Format	dotnet format Source/NexusTomorrow.slnx --verify-no-changes, after the build, because it loads the codec's generator from the build output
Test	Every test application, with a .trx report
Upload results	The test-results artifact, uploaded even when tests fail

Every action is pinned to a full commit. Running the tests shows how to dispatch it.

Known edges

• NexusTomorrow.Network.Auth and NexusTomorrow.Network.World still opt out of nullable reference types, switch their analysers off, and suppress the generator's NTC003 and NTC006 with <NoWarn>, until the codec's third stage settles each width from the client facts and brings them under the analysers. Their model classes keep their old names until then too, so ServerPathInitialise the class answers to ServerPathInitialize the opcode.
• The facts check pins 55 disagreements with the client facts, each with its reason, until the codec's third stage fixes them.
• The legacy snapshot is a second copy of every old model, about 1,180 files, until stage 3 deletes it. Its copies shadow the originals it references, on purpose: they're the ones it compares.
• GameMessageOpcode.cs still names one opcode by its number, Server_0x178_SoundTrigger. The duplicate value it used to declare is settled.
• MapGenerator and ClientConnector haven't been run against a real client since the nullable work changed how they read their settings.
• The old server's login front door, permissions and GM command definitions aren't here yet. They were part of the trunk that was deleted, and come back lifted from the old code when the core is ready for them.

Where the code lives

Piece	Path
The solution	Source/NexusTomorrow.slnx
Projects	Source/NexusTomorrow.*/
The codec	Source/NexusTomorrow.Network.Codec/
The generator	Source/NexusTomorrow.Network.Codec.Generator/
The converter	Tools/NexusTomorrow.ModelConverter/
The client facts table	Source/NexusTomorrow.Network.Codec/Facts/wire-facts-16042.jsonl
The hot-path switch and list	Directory.Build.targets, Build/HotPath/
Tests	Tests/NexusTomorrow.*.Tests/
Package versions	Directory.Packages.props
The workflow	.github/workflows/test.yml