zig-best-practices

# Zig Best Practices Follows type-first, functional, and error handling patterns from CLAUDE.md. This skill covers Zig-specific idioms only. ## Type System Patterns **Tagged unions for mutually exclusive states** — prevents invalid combinations that a struct with multiple nullable fields would allow: ```zig const RequestState = union(enum) { idle, loading, success: []const u8, failure: anyerror, }; ``` **Explicit error sets** — documents exactly what can fail; `anyerror` hides failure modes: ```zig const ParseError = error{ InvalidSyntax, UnexpectedToken, EndOfInput }; fn parse(input: []const u8) ParseError!Ast { ... } ``` **Distinct types for domain IDs** — compiler prevents mixing up different ID types: ```zig const UserId = enum(u64) { _ }; const OrderId = enum(u64) { _ }; ``` **Comptime validation** — catch invalid configurations at compile time, not runtime: ```zig fn Buffer(comptime size: usize) type { if (size == 0) @compileError("buffer size must be greater than 0"); return struct { data: [size]u8 = undefined, len: usize = 0 }; } ``` ## Memory Management - Pass allocators explicitly to every function that allocates; no global allocator state. - Place `defer resource.deinit()` immediately after acquisition — keeps cleanup co-located with creation. - Use `errdefer` for cleanup on error paths; `defer` for unconditional cleanup. - Use arena allocators for batch/temporary work; they free everything at once. - Use `std.testing.allocator` in t...