csharp-coding-standards

name	csharp-coding-standards
description	C# 13 coding standards for the YOS project — naming, formatting, nullability, and testing conventions. Use this when writing, reviewing, or refactoring any C# (.cs) file.

C# Coding Standards

Language Version

Use C# 13 features wherever applicable.

General

• Make only high-confidence suggestions when reviewing code changes.
• Handle edge cases and write clear exception handling.

Naming Conventions

• PascalCase for component names, method names, and public members.
• camelCase for private fields and local variables.
• Prefix interface names with I (e.g., IUserService).

Formatting

• Apply the code-formatting style defined in .editorconfig.
• Prefer file-scoped namespace declarations and single-line using directives.
• Insert a newline before the opening curly brace of any code block (after if, for, while, foreach, using, try, etc.).
• Always use braces for every control-flow clause (if, else, for, foreach, while, etc.) — even single-line bodies. Never omit braces.
• Ensure the final return statement of a method is on its own line.
• Use pattern matching and switch expressions wherever possible.
• Use nameof instead of string literals when referring to member names.
• Add XML doc comments on all public APIs; include <example> and <code> sections where applicable.

Nullable Reference Types

• Declare variables non-nullable; check for null only at entry points.
• Always use is null / is not null instead of == null / != null.
• Trust C# null annotations — do not add null checks when the type system guarantees a value cannot be null.

Testing

• Always include test cases for critical paths.
• Do not emit // Arrange, // Act, or // Assert comments.
• Match the naming style and capitalization of nearby test files.