Zig

Zig Project Rules

Agent Automation Commands

CRITICAL: Execute these commands after EVERY implementation (see AGENT_AUTOMATION module for full workflow).

# Complete quality check sequence:
zig fmt --check .         # Format check
zig build                 # Build verification
zig build test            # All tests (100% pass)

# No standard security audit tool for Zig yet

Zig Configuration

CRITICAL: Use Zig 0.11+ with strict compilation and comprehensive testing.

• Version: Zig 0.11+
• Recommended: Zig 0.13+
• Build System: zig build (built-in)
• Testing: zig test (built-in)
• Formatter: zig fmt (built-in)

build.zig Requirements

const std = @import("std");

pub fn build(b: *std.Build) void {
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

    // Library
    const lib = b.addStaticLibrary(.{
        .name = "your-lib",
        .root_source_file = .{ .path = "src/main.zig" },
        .target = target,
        .optimize = optimize,
    });
    b.installArtifact(lib);

    // Executable
    const exe = b.addExecutable(.{
        .name = "your-app",
        .root_source_file = .{ .path = "src/main.zig" },
        .target = target,
        .optimize = optimize,
    });
    b.installArtifact(exe);

    // Tests
    const main_tests = b.addTest(.{
        .root_source_file = .{ .path = "src/main.zig" },
        .target = target,
        .optimize = optimize,
    });

    const run_main_tests = b.addRunArtifact(main_tests);
    const test_step = b.step("test", "Run library tests");
    test_step.dependOn(&run_main_tests.step);

    // Run command
    const run_cmd = b.addRunArtifact(exe);
    run_cmd.step.dependOn(b.getInstallStep());
    if (b.args) |args| {
        run_cmd.addArgs(args);
    }

    const run_step = b.step("run", "Run the app");
    run_step.dependOn(&run_cmd.step);
}

Code Quality Standards

Mandatory Quality Checks

CRITICAL: After implementing ANY feature, you MUST run these commands in order.

IMPORTANT: These commands MUST match your GitHub Actions workflows to prevent CI/CD failures!

# Pre-Commit Checklist (MUST match .github/workflows/*.yml)

# 1. Format check (matches workflow)
zig fmt --check src/ tests/

# 2. Build (MUST pass - matches workflow)
zig build -Doptimize=ReleaseFast

# 3. Build with all optimizations (matches workflow)
zig build -Doptimize=ReleaseSmall
zig build -Doptimize=ReleaseSafe

# 4. Run all tests (MUST pass 100% - matches workflow)
zig build test

# 5. Test with different targets (matches workflow)
zig build test -Dtarget=x86_64-linux
zig build test -Dtarget=x86_64-windows
zig build test -Dtarget=aarch64-macos

# 6. Check for memory leaks (matches workflow)
zig build test -Doptimize=Debug --summary all

# If ANY fails: ❌ DO NOT COMMIT - Fix first!

If ANY of these fail, you MUST fix the issues before committing.

Why This Matters:

• Running different commands locally than in CI causes build failures
• Zig's compile-time guarantees only work if all checks pass
• Example: Using zig fmt src/ locally but zig fmt --check src/ in CI = failure
• Example: Only testing Debug builds locally = Release builds fail in CI
• Example: Not testing cross-compilation = deployment fails on target platform

Testing

• Framework: Built-in zig test
• Location: Tests can be inline or in /tests
• Coverage: Comprehensive test coverage required
• Memory: No leaks allowed (valgrind clean)

Example test structure:

const std = @import("std");
const testing = std.testing;
const DataProcessor = @import("processor.zig").DataProcessor;

test "DataProcessor: basic functionality" {
    var processor = DataProcessor.init(0.5);
    defer processor.deinit();
    
    const input = [_]i32{ 1, 2, 3, 4, 5 };
    const result = try processor.process(&input);
    defer testing.allocator.free(result);
    
    try testing.expect(result.len > 0);
    try testing.expectEqual(@as(usize, 3), result.len);
}

test "DataProcessor: handles empty input" {
    var processor = DataProcessor.init(0.5);
    defer processor.deinit();
    
    const input = [_]i32{};
    const result = try processor.process(&input);
    defer testing.allocator.free(result);
    
    try testing.expectEqual(@as(usize, 0), result.len);
}

test "DataProcessor: memory management" {
    // Test that all allocations are freed
    const allocator = testing.allocator;
    
    var processor = try DataProcessor.initWithAllocator(allocator, 0.5);
    defer processor.deinit();
    
    const input = try allocator.alloc(i32, 1000);
    defer allocator.free(input);
    
    for (input, 0..) |*item, i| {
        item.* = @intCast(i);
    }
    
    const result = try processor.process(input);
    defer allocator.free(result);
    
    // If we reach here without leaks, test passes
    try testing.expect(result.len > 0);
}

Memory Safety

CRITICAL: Zig provides compile-time safety - use it!

// ✅ GOOD: Safe memory management
const std = @import("std");

pub fn processData(allocator: std.mem.Allocator, input: []const i32) ![]i32 {
    var result = std.ArrayList(i32).init(allocator);
    defer result.deinit();  // Always cleanup!
    
    for (input) |value| {
        if (value > 0) {
            try result.append(value * 2);
        }
    }
    
    return result.toOwnedSlice();
}

// Usage with proper cleanup
pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    
    const allocator = gpa.allocator();
    
    const input = [_]i32{ 1, 2, 3, 4, 5 };
    const result = try processData(allocator, &input);
    defer allocator.free(result);  // Free returned memory!
    
    for (result) |value| {
        std.debug.print("{}\n", .{value});
    }
}

// ❌ BAD: Memory leaks
pub fn processDataLeaky(allocator: std.mem.Allocator) ![]i32 {
    var result = std.ArrayList(i32).init(allocator);
    // Missing defer result.deinit()!
    
    try result.append(42);
    return result.toOwnedSlice();  // Leaks ArrayList memory!
}

Best Practices

DO's ✅

• USE defer for cleanup
• CHECK all error returns
• VALIDATE all inputs
• TEST with different allocators
• USE comptime for compile-time computations
• PREFER stack allocation when possible
• USE tagged unions for variants
• CROSS-COMPILE to verify portability

DON'Ts ❌

• NEVER ignore error returns
• NEVER use undefined behavior
• NEVER leak memory
• NEVER use @ptrCast without validation
• NEVER assume platform specifics
• NEVER skip cross-compilation tests
• NEVER use global mutable state

CI/CD Requirements

Must include GitHub Actions workflows:

1. Testing (zig-test.yml):

   • Test on Linux, Windows, macOS
   • Test with Debug, ReleaseSafe, ReleaseFast, ReleaseSmall
   • Cross-compilation tests
   • Memory leak detection

2. Linting (zig-lint.yml):

   • zig fmt --check
   • Build verification
   • All optimize modes