xtask: make version.rs compile here and register cargo xtask version

version.rs (ported from PhotoCraft) called crate::cargo() and a two-argument
crate::run() that don't exist in this xtask, so xtask didn't build at all.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

xtask/src/main.rs

@@ -15,6 +15,7 @@ type Command = fn(&[String]) -> anyhow::Result<()>;
 
 /// Every subcommand: name, one-line summary, entry point.
 const COMMANDS: &[(&str, &str, Command)] = &[
+    ("version", "Print the workspace version, or `version set X.Y.Z[-pre]` to change it and refresh Cargo.lock", version_cmd),
     ("layers", "Enforce the crate dependency layering (plan/architecture.md §3)", gates::layers),
     ("wasm", "cargo check --target wasm32-unknown-unknown for every crate below L8", gates::wasm),
     ("deny", "Dependency licences, bans, sources and advisories (deny.toml; needs cargo-deny)", gates::deny),
@@ -29,6 +30,11 @@ const COMMANDS: &[(&str, &str, Command)] = &[
     ("demo-pdf", "Build dist/demo/printcraft-showcase.pdf (needs Google Chrome or Chromium)", demo_pdf::run),
 ];
 
+fn version_cmd(args: &[String]) -> anyhow::Result<()> {
+    let args: Vec<&str> = args.iter().map(String::as_str).collect();
+    version::run(&gates::root(), &args).map_err(anyhow::Error::msg)
+}
+
 fn main() -> ExitCode {
     let args: Vec<String> = std::env::args().skip(1).collect();
     let Some(name) = args.first() else {

xtask/src/version.rs

@@ -8,10 +8,7 @@ use std::path::Path;
 /// The `version = "…"` value inside `[workspace.package]`.
 pub fn read(manifest: &str) -> Result<String, String> {
     let (_, line) = find_line(manifest)?;
-    let v = line
-        .split_once('=')
-        .map(|(_, v)| v.trim().trim_matches('"').to_string())
-        .unwrap_or_default();
+    let v = line.split_once('=').map(|(_, v)| v.trim().trim_matches('"').to_string()).unwrap_or_default();
     if v.is_empty() {
         return Err("empty [workspace.package] version".into());
     }
@@ -48,20 +45,11 @@ pub fn validate(v: &str) -> Result<(), String> {
         None => (v, None),
     };
     let nums: Vec<&str> = core.split('.').collect();
-    if nums.len() != 3
-        || nums.iter().any(|n| {
-            n.is_empty()
-                || !n.bytes().all(|b| b.is_ascii_digit())
-                || (n.len() > 1 && n.starts_with('0'))
-        })
-    {
+    if nums.len() != 3 || nums.iter().any(|n| n.is_empty() || !n.bytes().all(|b| b.is_ascii_digit()) || (n.len() > 1 && n.starts_with('0'))) {
         return bad();
     }
     if let Some(p) = pre
-        && (p.is_empty()
-            || p.split('.').any(|id| {
-                id.is_empty() || !id.bytes().all(|b| b.is_ascii_alphanumeric() || b == b'-')
-            }))
+        && (p.is_empty() || p.split('.').any(|id| id.is_empty() || !id.bytes().all(|b| b.is_ascii_alphanumeric() || b == b'-')))
     {
         return bad();
     }
@@ -104,12 +92,17 @@ pub fn run(root: &Path, args: &[&str]) -> Result<(), String> {
             std::fs::write(&tmp, updated).map_err(|e| format!("write {}: {e}", tmp.display()))?;
             std::fs::rename(&tmp, &path).map_err(|e| format!("replace {}: {e}", path.display()))?;
             // Refresh the workspace members' entries in Cargo.lock (no dependency upgrades).
-            let mut c = crate::cargo();
-            c.args(["update", "--workspace", "--offline"]);
-            if crate::run(c, "cargo update --workspace --offline").is_err() {
-                let mut c = crate::cargo();
-                c.args(["update", "--workspace"]);
-                crate::run(c, "cargo update --workspace")?;
+            let cargo_update = |extra: &[&str]| -> Result<(), String> {
+                let st = std::process::Command::new(env!("CARGO"))
+                    .current_dir(root)
+                    .args(["update", "--workspace"])
+                    .args(extra)
+                    .status()
+                    .map_err(|e| format!("cargo update: {e}"))?;
+                if st.success() { Ok(()) } else { Err(format!("cargo update --workspace {} failed", extra.join(" "))) }
+            };
+            if cargo_update(&["--offline"]).is_err() {
+                cargo_update(&[])?;
             }
             println!("version: {old} -> {new}");
             Ok(())