Signed release pipeline (macOS/Windows/Linux/Web); README community note

Ports photocraft's release workflow + packaging (signing, notarization,
MSI/DMG/deb/rpm/AppImage/web), adds `cargo xtask version`. File-type
associations omitted for now (route B); app keeps its own .desktop. Fresh
WiX UpgradeCode. README 'about' note updated.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

xtask/src/main.rs

@@ -8,6 +8,7 @@ mod bundle;
 mod ico;
 mod layers;
 mod stats;
+mod version;
 
 use std::path::{Path, PathBuf};
 use std::process::{Command, ExitCode};
@@ -39,6 +40,7 @@ fn main() -> ExitCode {
         Some("corpus") => cmd_corpus(rest.contains(&"--download")),
         Some("bundle") => bundle::run(&root()),
         Some("ico") => ico::run(&rest),
+        Some("version") => version::run(&root(), &rest),
         Some("stats") => stats::run(&root(), rest.contains(&"--exact")),
         Some("-h" | "--help" | "help") | None => {
             print!("{USAGE}");

xtask/src/version.rs

@@ -0,0 +1,164 @@
+//! `cargo xtask version [set X.Y.Z[-pre]]`: the workspace version, the single source of truth.
+//!
+//! The version lives in `[workspace.package] version` in the root `Cargo.toml`; every crate
+//! inherits it with `version.workspace = true`, and the packaging scripts read it from here.
+
+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();
+    if v.is_empty() {
+        return Err("empty [workspace.package] version".into());
+    }
+    Ok(v)
+}
+
+/// `manifest` with the workspace version replaced; everything else is byte-for-byte unchanged.
+pub fn replace(manifest: &str, new: &str) -> Result<String, String> {
+    validate(new)?;
+    let (idx, _) = find_line(manifest)?;
+    let mut out = String::with_capacity(manifest.len() + 8);
+    for (i, line) in manifest.split_inclusive('\n').enumerate() {
+        if i == idx {
+            let eol = if line.ends_with("\r\n") {
+                "\r\n"
+            } else if line.ends_with('\n') {
+                "\n"
+            } else {
+                ""
+            };
+            out.push_str(&format!("version = \"{new}\"{eol}"));
+        } else {
+            out.push_str(line);
+        }
+    }
+    Ok(out)
+}
+
+/// Semver without build metadata: `MAJOR.MINOR.PATCH` plus an optional `-pre.release` tag.
+pub fn validate(v: &str) -> Result<(), String> {
+    let bad = || Err(format!("`{v}` is not a version like 1.2.3 or 1.2.3-rc.1"));
+    let (core, pre) = match v.split_once('-') {
+        Some((c, p)) => (c, Some(p)),
+        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'))
+        })
+    {
+        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'-')
+            }))
+    {
+        return bad();
+    }
+    Ok(())
+}
+
+/// Index and text of the `version` line in `[workspace.package]`.
+fn find_line(manifest: &str) -> Result<(usize, &str), String> {
+    let mut in_section = false;
+    for (i, line) in manifest.lines().enumerate() {
+        let t = line.trim();
+        if t.starts_with('[') {
+            in_section = t == "[workspace.package]";
+            continue;
+        }
+        if in_section
+            && let Some(rest) = t.strip_prefix("version")
+            && rest.trim_start().starts_with('=')
+        {
+            return Ok((i, line));
+        }
+    }
+    Err("no `version = \"…\"` in [workspace.package] of the root Cargo.toml".into())
+}
+
+pub fn run(root: &Path, args: &[&str]) -> Result<(), String> {
+    let path = root.join("Cargo.toml");
+    let text = std::fs::read_to_string(&path).map_err(|e| format!("read {}: {e}", path.display()))?;
+    match args {
+        [] => {
+            println!("{}", read(&text)?);
+            Ok(())
+        }
+        ["set", new] => {
+            let old = read(&text)?;
+            let updated = replace(&text, new)?;
+            // Write atomically: a half-written root manifest breaks every build in the workspace.
+            let tmp = root.join("target").join("Cargo.toml.xtask-version");
+            std::fs::create_dir_all(root.join("target")).map_err(|e| format!("create target/: {e}"))?;
+            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")?;
+            }
+            println!("version: {old} -> {new}");
+            Ok(())
+        }
+        _ => Err("usage: cargo xtask version [set X.Y.Z[-pre]]".into()),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const MANIFEST: &str = "[workspace]\nmembers = [\"a\"]\n\n[workspace.package]\nversion = \"0.1.0\"\nedition = \"2024\"\n\n[workspace.dependencies]\nfoo = { version = \"1\" }\n";
+
+    #[test]
+    fn reads_the_workspace_version() {
+        assert_eq!(read(MANIFEST).unwrap(), "0.1.0");
+        assert!(read("[package]\nversion = \"1.0.0\"\n").is_err());
+    }
+
+    #[test]
+    fn replaces_only_the_workspace_version() {
+        let out = replace(MANIFEST, "1.2.3-rc.1").unwrap();
+        assert_eq!(read(&out).unwrap(), "1.2.3-rc.1");
+        assert_eq!(out, MANIFEST.replace("version = \"0.1.0\"", "version = \"1.2.3-rc.1\""));
+        assert!(out.contains("foo = { version = \"1\" }"));
+    }
+
+    #[test]
+    fn keeps_crlf_line_endings() {
+        let crlf = MANIFEST.replace('\n', "\r\n");
+        let out = replace(&crlf, "2.0.0").unwrap();
+        assert_eq!(out, crlf.replace("\"0.1.0\"", "\"2.0.0\""));
+    }
+
+    #[test]
+    fn validates_versions() {
+        for ok in ["0.1.0", "1.20.300", "1.0.0-rc.1", "1.0.0-alpha", "1.0.0-x-y.2"] {
+            assert!(validate(ok).is_ok(), "{ok}");
+        }
+        for bad in ["1.0", "1.0.0.0", "v1.0.0", "01.0.0", "1.0.0-", "1.0.0-a..b", "1.0.0+meta", "1.a.0", ""] {
+            assert!(validate(bad).is_err(), "{bad}");
+        }
+        assert!(replace(MANIFEST, "nope").is_err());
+    }
+
+    #[test]
+    fn the_real_manifest_has_a_valid_version() {
+        let text = std::fs::read_to_string(crate::root().join("Cargo.toml")).unwrap();
+        validate(&read(&text).unwrap()).unwrap();
+    }
+}