C# on .NET

Default: the current LTS .NET SDK, nullable reference types on, warnings as errors, xUnit, dotnet publish self-contained.

Setup

1. dotnet new console -n App and dotnet new xunit -n App.Tests; add both to a solution.
2. In the project file: <Nullable>enable</Nullable>, <TreatWarningsAsErrors>true</TreatWarningsAsErrors>, <ImplicitUsings>enable</ImplicitUsings>.
3. Pin the SDK with global.json so CI and every machine build with the same compiler.
4. A machine without admin rights can install the SDK per user with the official dotnet-install script; put it on PATH only where it is used.

Command-line tools

• Use System.CommandLine for parsing; it gives help, validation and tab completion.
• Keep the core logic in a library project and the CLI as a thin layer; test the library.
• Return non-zero exit codes on failure; write data to stdout and messages to stderr.

Desktop games with Raylib-cs

• Separate the simulation (plain classes, deterministic, testable with xUnit) from drawing.
• Measure frame time with a real clock over a window (e.g. 1 s) and report mean and worst; a single fps number hides stutter. Add a --stats flag rather than guessing.
• Provide a headless mode (--bench, --screenshot <scene>) so balance and images can be produced without playing.
• Load fonts with the exact set of code points the UI uses (collect them from all string tables at start-up). Loading only ASCII makes every Japanese or accented character render as ?.
• Font collections (.ttc) cannot be passed directly to loaders that expect a single font; extract the face you need first, then verify every required glyph exists in its cmap.

Persistence

• Give save data a version number and migrate forward step by step (v1 → v2 → v3). Test each migration with a stored fixture of the old format.
• Write saves atomically (temp file + File.Move(..., overwrite: true)).

Publishing

dotnet publish -c Release -r win-x64 --self-contained -p:PublishSingleFile=true
dotnet publish -c Release -r linux-x64 --self-contained -p:PublishSingleFile=true

• Self-contained avoids "install the runtime first" support issues; check the output size and keep it in the release notes.
• Native libraries (raylib) must be present for each runtime identifier; test the published binary on a clean machine or VM.

Verification loop

1. dotnet build with zero warnings.
2. dotnet test — unit tests plus a deterministic benchmark (fixed seed → known outcome ranges).
3. Run the published binary, not dotnet run, before release.

Pitfalls

• Culture-sensitive formatting: double.Parse and ToString() follow the OS locale. Use CultureInfo.InvariantCulture for files and protocols.
• async void swallows exceptions except in event handlers.
• Floating-point determinism differs across platforms and JIT settings; do not rely on bit-identical physics for replays across machines without fixed-point or careful ordering.
• Disposing native resources: textures, sounds and fonts from native libraries are not garbage-collected promptly; unload them explicitly.
• WSL or remote desktops may render through a software path; measure performance on the target hardware before tuning.