feat(xtask): cross-platform release build via cargo-zigbuild

Replace build-all.sh shell script with a Rust xtask workspace member.
Uses cargo-zigbuild + zig as a universal cross-linker -- no VMs, no
containers, no root required.

Produces all three release binaries from a single FreeBSD machine:
  anvil-X.Y.Z-freebsd-x86_64.tar.gz  (native cargo build)
  anvil-X.Y.Z-linux-x86_64.tar.gz    (cargo zigbuild)
  anvil-X.Y.Z-windows-x86_64.zip     (cargo zigbuild)

Commands:
  cargo xtask --fix     install zig, zip, cargo-zigbuild, rustup targets
  cargo xtask --check   verify all dependencies
  cargo xtask           build all three binaries + SHA256SUMS
  cargo xtask --clean   remove cross-compile artifacts
  cargo xtask --suffix rc1  build with version suffix

Also converts Cargo.toml to a workspace (members: anvil, xtask).
build-all.sh retained as a thin wrapper around cargo xtask.

xtask/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "xtask"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[[bin]]
+name = "xtask"
+path = "src/main.rs"
+
+[dependencies]
+# CLI argument parsing
+clap = { version = "4.4", features = ["derive"] }
+# Error handling
+anyhow = "1.0"
+# Colors
+colored = "2.1"
+# Command existence check
+which = "5.0"

xtask/src/main.rs

@@ -0,0 +1,667 @@
+//! xtask -- build automation for Anvil.
+//!
+//! Usage:
+//!   cargo xtask                     Build all platform binaries
+//!   cargo xtask --check             Check dependencies
+//!   cargo xtask --fix               Install missing dependencies
+//!   cargo xtask --clean             Remove zig/cargo cross-compile cache
+//!   cargo xtask --suffix rc1        Build with version suffix (e.g. 1.0.0-rc1)
+//!
+//! Produces:
+//!   release-artifacts/anvil-X.Y.Z-freebsd-x86_64.tar.gz  (native)
+//!   release-artifacts/anvil-X.Y.Z-linux-x86_64.tar.gz    (via cargo-zigbuild)
+//!   release-artifacts/anvil-X.Y.Z-windows-x86_64.zip     (via cargo-zigbuild)
+
+use anyhow::{bail, Context, Result};
+use clap::Parser;
+use colored::*;
+use std::env;
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::process::{Command, Stdio};
+
+// ---------------------------------------------------------------------------
+// CLI
+// ---------------------------------------------------------------------------
+
+#[derive(Parser, Debug)]
+#[command(
+    name = "xtask",
+    about = "Build Anvil release binaries for all platforms",
+    long_about = "Builds FreeBSD (native), Linux, and Windows binaries using cargo-zigbuild.\n\
+                  No VMs, no root, no containers required.\n\n\
+                  First time: cargo xtask --fix\n\
+                  Every release: cargo xtask"
+)]
+struct Args {
+    /// Check dependencies and report what is missing
+    #[arg(long)]
+    check: bool,
+
+    /// Install missing dependencies (zig, cargo-zigbuild, rustup targets)
+    #[arg(long)]
+    fix: bool,
+
+    /// Remove cargo target directories for cross-compile targets
+    #[arg(long)]
+    clean: bool,
+
+    /// Version suffix (e.g. rc1 -> 1.0.0-rc1)
+    #[arg(long, value_name = "SUFFIX")]
+    suffix: Option<String>,
+}
+
+// ---------------------------------------------------------------------------
+// Targets
+// ---------------------------------------------------------------------------
+
+#[allow(dead_code)]
+struct Target {
+    name: &'static str,
+    triple: &'static str,
+    binary_name: &'static str,
+    archive_ext: &'static str,
+}
+
+const TARGETS: &[Target] = &[
+    Target {
+        name: "Linux x86_64",
+        triple: "x86_64-unknown-linux-gnu",
+        binary_name: "anvil",
+        archive_ext: "tar.gz",
+    },
+    Target {
+        name: "Windows x86_64",
+        triple: "x86_64-pc-windows-gnu",
+        binary_name: "anvil.exe",
+        archive_ext: "zip",
+    },
+];
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+fn ok(msg: &str) {
+    println!("{}   {}", "ok".green(), msg);
+}
+
+fn warn(msg: &str) {
+    println!("{}  {}", "warn".yellow(), msg);
+}
+
+fn info(msg: &str) {
+    println!("{}  {}", "....".cyan(), msg);
+}
+
+fn fail(msg: &str) {
+    eprintln!("{}  {}", "FAIL".red(), msg);
+}
+
+fn header(msg: &str) {
+    println!("\n{}\n", format!("=== {} ===", msg).bold());
+}
+
+fn cmd_exists(cmd: &str) -> bool {
+    which::which(cmd).is_ok()
+}
+
+fn run(program: &str, args: &[&str], cwd: Option<&Path>) -> Result<()> {
+    let mut cmd = Command::new(program);
+    cmd.args(args);
+    if let Some(dir) = cwd {
+        cmd.current_dir(dir);
+    }
+    let status = cmd
+        .status()
+        .with_context(|| format!("Failed to run: {} {}", program, args.join(" ")))?;
+    if !status.success() {
+        bail!("{} {} failed with exit code: {}", program, args.join(" "), status);
+    }
+    Ok(())
+}
+
+fn run_captured(program: &str, args: &[&str]) -> Result<String> {
+    let output = Command::new(program)
+        .args(args)
+        .stdout(Stdio::piped())
+        .stderr(Stdio::null())
+        .output()
+        .with_context(|| format!("Failed to run: {}", program))?;
+    Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
+}
+
+/// Find the workspace root.
+/// When run via `cargo xtask`, cargo sets CARGO_MANIFEST_DIR to the xtask
+/// package directory. The workspace root is one level up from there.
+fn workspace_root() -> Result<PathBuf> {
+    // CARGO_MANIFEST_DIR points to xtask/ -- parent is the workspace root
+    if let Ok(manifest_dir) = env::var("CARGO_MANIFEST_DIR") {
+        let xtask_dir = PathBuf::from(manifest_dir);
+        if let Some(parent) = xtask_dir.parent() {
+            if parent.join("Cargo.toml").exists() {
+                return Ok(parent.to_path_buf());
+            }
+        }
+    }
+    // Fallback: walk up from current dir looking for a workspace Cargo.toml
+    let mut dir = env::current_dir()?;
+    loop {
+        let cargo_toml = dir.join("Cargo.toml");
+        if cargo_toml.exists() {
+            // Check if it's a workspace (contains [workspace])
+            let contents = fs::read_to_string(&cargo_toml).unwrap_or_default();
+            if contents.contains("[workspace]") {
+                return Ok(dir);
+            }
+        }
+        if !dir.pop() {
+            bail!("Could not find workspace root (no Cargo.toml with [workspace] found)");
+        }
+    }
+}
+
+/// Read version from workspace Cargo.toml
+fn read_version(workspace: &Path) -> Result<String> {
+    let cargo_toml = fs::read_to_string(workspace.join("Cargo.toml"))
+        .context("Failed to read Cargo.toml")?;
+    for line in cargo_toml.lines() {
+        let line = line.trim();
+        if line.starts_with("version") && line.contains('=') {
+            if let Some(v) = line.split('=').nth(1) {
+                let v = v.trim().trim_matches('"');
+                return Ok(v.to_string());
+            }
+        }
+    }
+    bail!("Could not read version from Cargo.toml")
+}
+
+/// Detect host OS
+fn host_os() -> &'static str {
+    if cfg!(target_os = "freebsd") {
+        "freebsd"
+    } else if cfg!(target_os = "linux") {
+        "linux"
+    } else if cfg!(target_os = "macos") {
+        "macos"
+    } else if cfg!(target_os = "windows") {
+        "windows"
+    } else {
+        "unknown"
+    }
+}
+
+/// Archive binary into release-artifacts/
+fn package_binary(
+    workspace: &Path,
+    triple: &str,
+    binary_name: &str,
+    archive_name: &str,
+    archive_ext: &str,
+) -> Result<()> {
+    let artifacts = workspace.join("release-artifacts");
+    fs::create_dir_all(&artifacts)?;
+
+    let binary_path = workspace
+        .join("target")
+        .join(triple)
+        .join("release")
+        .join(binary_name);
+
+    if !binary_path.exists() {
+        // Show what's actually in the target dir to help diagnose
+        let target_dir = binary_path.parent().unwrap();
+        let entries: Vec<String> = fs::read_dir(target_dir)
+            .map(|rd| rd.flatten()
+                .map(|e| e.file_name().to_string_lossy().to_string())
+                .collect())
+            .unwrap_or_default();
+        bail!(
+            "Binary not found: {}\n  Contents of {}:\n    {}",
+            binary_path.display(),
+            target_dir.display(),
+            if entries.is_empty() { "(empty)".to_string() } else { entries.join(", ") }
+        );
+    }
+
+    match archive_ext {
+        "tar.gz" => {
+            let archive = artifacts.join(format!("{}.tar.gz", archive_name));
+            run(
+                "tar",
+                &[
+                    "-czf",
+                    archive.to_str().unwrap(),
+                    "-C",
+                    binary_path.parent().unwrap().to_str().unwrap(),
+                    binary_name,
+                ],
+                None,
+            )?;
+        }
+        "zip" => {
+            let archive = artifacts.join(format!("{}.zip", archive_name));
+            // -j = junk paths (store just the filename, not the full path)
+            run(
+                "zip",
+                &["-q", "-j", archive.to_str().unwrap(), binary_path.to_str().unwrap()],
+                None,
+            )?;
+        }
+        _ => bail!("Unknown archive format: {}", archive_ext),
+    }
+
+    Ok(())
+}
+
+/// Package native FreeBSD binary from target/release/
+fn package_native(workspace: &Path, archive_name: &str) -> Result<()> {
+    let artifacts = workspace.join("release-artifacts");
+    fs::create_dir_all(&artifacts)?;
+
+    let binary_path = workspace.join("target").join("release").join("anvil");
+    if !binary_path.exists() {
+        bail!("Native binary not found: {}", binary_path.display());
+    }
+
+    let archive = artifacts.join(format!("{}.tar.gz", archive_name));
+    run(
+        "tar",
+        &[
+            "-czf",
+            archive.to_str().unwrap(),
+            "-C",
+            binary_path.parent().unwrap().to_str().unwrap(),
+            "anvil",
+        ],
+        None,
+    )?;
+
+    Ok(())
+}
+
+/// Generate SHA256SUMS in release-artifacts/
+fn generate_checksums(workspace: &Path) -> Result<()> {
+    let artifacts = workspace.join("release-artifacts");
+    let prev = env::current_dir()?;
+    env::set_current_dir(&artifacts)?;
+
+    // Collect artifact files
+    let mut files: Vec<String> = fs::read_dir(&artifacts)?
+        .flatten()
+        .filter_map(|e| {
+            let name = e.file_name().to_string_lossy().to_string();
+            if name != "SHA256SUMS" {
+                Some(name)
+            } else {
+                None
+            }
+        })
+        .collect();
+    files.sort();
+
+    if cmd_exists("sha256sum") {
+        let mut args = vec!["--"];
+        for f in &files {
+            args.push(f.as_str());
+        }
+        let output = Command::new("sha256sum")
+            .args(&args)
+            .output()?;
+        fs::write("SHA256SUMS", &output.stdout)?;
+    } else if cmd_exists("shasum") {
+        let mut args = vec!["-a", "256", "--"];
+        for f in &files {
+            args.push(f.as_str());
+        }
+        let output = Command::new("shasum")
+            .args(&args)
+            .output()?;
+        fs::write("SHA256SUMS", &output.stdout)?;
+    }
+
+    let checksums = fs::read_to_string("SHA256SUMS").unwrap_or_default();
+    print!("{}", checksums);
+
+    env::set_current_dir(prev)?;
+    Ok(())
+}
+
+// ---------------------------------------------------------------------------
+// Check
+// ---------------------------------------------------------------------------
+
+fn run_check(_workspace: &Path) -> Result<bool> {
+    header("Checking dependencies");
+    let mut missing = 0;
+
+    // zig
+    if cmd_exists("zig") {
+        let ver = run_captured("zig", &["version"]).unwrap_or_default();
+        ok(&format!("zig {}", ver));
+    } else {
+        warn("zig -- not found");
+        println!("       {}", "sudo pkg install zig  (FreeBSD)  or  apt install zig  (Linux)");
+        missing += 1;
+    }
+
+    // zip (for Windows archive)
+    if cmd_exists("zip") {
+        ok("zip");
+    } else {
+        warn("zip -- not found");
+        println!("       {}", "sudo pkg install zip  (FreeBSD)  or  apt install zip  (Linux)");
+        missing += 1;
+    }
+
+    // cargo-zigbuild
+    if cmd_exists("cargo-zigbuild") {
+        let ver = run_captured("cargo-zigbuild", &["--version"])
+            .unwrap_or_default();
+        ok(&format!("cargo-zigbuild {}", ver.replace("cargo-zigbuild ", "")));
+    } else {
+        warn("cargo-zigbuild -- not found");
+        println!("       {}", "cargo install cargo-zigbuild");
+        missing += 1;
+    }
+
+    // rustup targets
+    if cmd_exists("rustup") {
+        let targets = run_captured("rustup", &["target", "list", "--installed"])
+            .unwrap_or_default();
+        for t in TARGETS {
+            if targets.contains(t.triple) {
+                ok(&format!("rustup target: {}", t.triple));
+            } else {
+                warn(&format!("rustup target: {} -- not installed", t.triple));
+                println!("       rustup target add {}", t.triple);
+                missing += 1;
+            }
+        }
+    } else {
+        warn("rustup -- not found");
+        println!("       {}", "curl https://sh.rustup.rs -sSf | sh");
+        missing += 1;
+    }
+
+    // Host platform note
+    let host = host_os();
+    if host == "linux" {
+        println!();
+        warn("Running on Linux -- FreeBSD binary cannot be produced.");
+        println!("       Boot into FreeBSD and run 'cargo xtask' for the FreeBSD binary.");
+    } else if host != "freebsd" {
+        println!();
+        warn(&format!("Unsupported host OS: {}", host));
+    }
+
+    println!();
+    if missing == 0 {
+        ok("All dependencies satisfied -- ready to build!");
+        Ok(true)
+    } else {
+        warn(&format!("{} dependency/dependencies missing. Run: cargo xtask --fix", missing));
+        Ok(false)
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Fix
+// ---------------------------------------------------------------------------
+
+fn run_fix() -> Result<()> {
+    header("Installing dependencies");
+
+    let host = host_os();
+
+    // zig
+    if cmd_exists("zig") {
+        ok("zig already installed");
+    } else {
+        info("Installing zig...");
+        match host {
+            "freebsd" => run("sudo", &["pkg", "install", "-y", "zig"], None)?,
+            "linux" => {
+                // Try common package managers
+                if cmd_exists("apt-get") {
+                    run("sudo", &["apt-get", "install", "-y", "zig"], None)?;
+                } else if cmd_exists("dnf") {
+                    run("sudo", &["dnf", "install", "-y", "zig"], None)?;
+                } else {
+                    bail!("Could not install zig automatically. Install manually: https://ziglang.org/download/");
+                }
+            }
+            _ => bail!("Cannot auto-install zig on {}. Install manually: https://ziglang.org/download/", host),
+        }
+        ok("zig installed");
+    }
+
+    // zip (for Windows archive packaging)
+    if cmd_exists("zip") {
+        ok("zip already installed");
+    } else {
+        info("Installing zip...");
+        match host {
+            "freebsd" => run("sudo", &["pkg", "install", "-y", "zip"], None)?,
+            "linux" => {
+                if cmd_exists("apt-get") {
+                    run("sudo", &["apt-get", "install", "-y", "zip"], None)?;
+                } else if cmd_exists("dnf") {
+                    run("sudo", &["dnf", "install", "-y", "zip"], None)?;
+                } else {
+                    bail!("Could not install zip automatically. Install it manually.");
+                }
+            }
+            _ => bail!("Cannot auto-install zip on {}. Install it manually.", host),
+        }
+        ok("zip installed");
+    }
+
+    // cargo-zigbuild
+    if cmd_exists("cargo-zigbuild") {
+        ok("cargo-zigbuild already installed");
+    } else {
+        info("Installing cargo-zigbuild...");
+        run("cargo", &["install", "cargo-zigbuild"], None)?;
+        ok("cargo-zigbuild installed");
+    }
+
+    // rustup targets
+    if cmd_exists("rustup") {
+        let installed = run_captured("rustup", &["target", "list", "--installed"])
+            .unwrap_or_default();
+        for t in TARGETS {
+            if installed.contains(t.triple) {
+                ok(&format!("rustup target {} already installed", t.triple));
+            } else {
+                info(&format!("Adding rustup target {}...", t.triple));
+                run("rustup", &["target", "add", t.triple], None)?;
+                ok(&format!("rustup target {} added", t.triple));
+            }
+        }
+    } else {
+        bail!("rustup not found -- install it first: curl https://sh.rustup.rs -sSf | sh");
+    }
+
+    println!();
+    ok("All dependencies installed. Run: cargo xtask");
+    Ok(())
+}
+
+// ---------------------------------------------------------------------------
+// Clean
+// ---------------------------------------------------------------------------
+
+fn run_clean(workspace: &Path) -> Result<()> {
+    header("Cleaning cross-compile artifacts");
+
+    for t in TARGETS {
+        let target_dir = workspace.join("target").join(t.triple);
+        if target_dir.exists() {
+            info(&format!("Removing target/{}/...", t.triple));
+            fs::remove_dir_all(&target_dir)?;
+            ok(&format!("target/{} removed", t.triple));
+        } else {
+            ok(&format!("target/{} already clean", t.triple));
+        }
+    }
+
+    let artifacts = workspace.join("release-artifacts");
+    if artifacts.exists() {
+        info("Removing release-artifacts/...");
+        fs::remove_dir_all(&artifacts)?;
+        ok("release-artifacts removed");
+    }
+
+    println!();
+    ok("Clean complete.");
+    Ok(())
+}
+
+// ---------------------------------------------------------------------------
+// Build
+// ---------------------------------------------------------------------------
+
+fn run_build(workspace: &Path, version: &str) -> Result<()> {
+    let host = host_os();
+
+    println!();
+    println!("{}", format!("Building Anvil v{} -- all platforms", version).bold());
+    println!("  Version:  {} (from Cargo.toml)", version);
+    println!("  Host:     {}", host);
+
+    // Clean previous artifacts
+    let artifacts = workspace.join("release-artifacts");
+    if artifacts.exists() {
+        fs::remove_dir_all(&artifacts)?;
+    }
+    fs::create_dir_all(&artifacts)?;
+
+    // -- FreeBSD native ----------------------------------------------------
+    if host == "freebsd" {
+        header("FreeBSD x86_64");
+        info("Building...");
+        run("cargo", &["build", "--release"], Some(workspace))?;
+        let archive_name = format!("anvil-{}-freebsd-x86_64", version);
+        package_native(workspace, &archive_name)?;
+        ok(&format!("{}.tar.gz", archive_name));
+    } else if host == "linux" {
+        println!();
+        warn("Running on Linux -- FreeBSD binary cannot be produced.");
+        println!("  Boot into FreeBSD and run 'cargo xtask' for the FreeBSD binary.");
+        println!();
+    }
+
+    // -- Linux x86_64 via cargo-zigbuild -----------------------------------
+    header("Linux x86_64 (via cargo-zigbuild)");
+    info("Building...");
+    run(
+        "cargo",
+        &["zigbuild", "--release", "--target", "x86_64-unknown-linux-gnu"],
+        Some(workspace),
+    )?;
+    let archive_name = format!("anvil-{}-linux-x86_64", version);
+    package_binary(
+        workspace,
+        "x86_64-unknown-linux-gnu",
+        "anvil",
+        &archive_name,
+        "tar.gz",
+    )?;
+    ok(&format!("{}.tar.gz", archive_name));
+
+    // -- Windows x86_64 via cargo-zigbuild ---------------------------------
+    header("Windows x86_64 (via cargo-zigbuild)");
+    info("Building...");
+    run(
+        "cargo",
+        &["zigbuild", "--release", "--target", "x86_64-pc-windows-gnu"],
+        Some(workspace),
+    )?;
+    let archive_name = format!("anvil-{}-windows-x86_64", version);
+    package_binary(
+        workspace,
+        "x86_64-pc-windows-gnu",
+        "anvil.exe",
+        &archive_name,
+        "zip",
+    )?;
+    ok(&format!("{}.zip", archive_name));
+
+    // -- Checksums ---------------------------------------------------------
+    header("Checksums");
+    generate_checksums(workspace)?;
+
+    // -- Summary -----------------------------------------------------------
+    println!();
+    println!("{}", format!("=== Anvil v{} ready ===", version).bold().green());
+    println!();
+    for entry in fs::read_dir(&artifacts)?.flatten() {
+        let meta = entry.metadata()?;
+        println!(
+            "  {} ({:.1} MB)",
+            entry.file_name().to_string_lossy(),
+            meta.len() as f64 / 1_048_576.0
+        );
+    }
+    println!();
+    println!("Upload to Gitea:");
+    println!("  1. Releases -> New Release -> Tag: v{}", version);
+    println!("  2. Drag and drop everything from release-artifacts/");
+    println!("  3. Save");
+    println!();
+
+    Ok(())
+}
+
+// ---------------------------------------------------------------------------
+// Main
+// ---------------------------------------------------------------------------
+
+fn main() {
+    let args = Args::parse();
+    let workspace = workspace_root().expect("Could not find workspace root");
+
+    let result = if args.clean {
+        run_clean(&workspace)
+    } else if args.check {
+        match run_check(&workspace) {
+            Ok(true) => Ok(()),
+            Ok(false) => std::process::exit(1),
+            Err(e) => Err(e),
+        }
+    } else if args.fix {
+        run_fix()
+    } else {
+        // Build -- check deps first
+        match run_check(&workspace) {
+            Ok(false) => {
+                println!();
+                fail("Dependencies missing.");
+                fail("Run: cargo xtask --fix");
+                println!();
+                std::process::exit(1);
+            }
+            Err(e) => {
+                fail(&format!("Dependency check failed: {}", e));
+                std::process::exit(1);
+            }
+            Ok(true) => {}
+        }
+
+        let base_version =
+            read_version(&workspace).expect("Could not read version from Cargo.toml");
+        let version = match &args.suffix {
+            Some(s) => format!("{}-{}", base_version, s.trim_start_matches('v')),
+            None => base_version,
+        };
+
+        run_build(&workspace, &version)
+    };
+
+    if let Err(e) = result {
+        fail(&format!("{:#}", e));
+        std::process::exit(1);
+    }
+}