From 16285cd62e226d1d4c4a0ef22c3b0ad65753d363 Mon Sep 17 00:00:00 2001
From: smittie2000 <smittie2000@gmail.com>
Date: Sat, 24 Oct 2026 07:43:05 +0200
Subject: [PATCH] xtask local: order pre-releases by semver (rc.10 after rc.9)
 (#820)

compare_versions compared pre-release tags as plain strings, so
1.0.0-rc.10 sorted before 1.0.0-rc.9. `cargo xtask local` uses it to pick
the newest mirrored build for `status` and to choose what `prune` keeps,
so a tenth release candidate would have been treated as older than the
ninth and pruned first.

Parse with the workspace's semver crate and compare by precedence, which
orders numeric pre-release parts as numbers.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
---
 Cargo.lock         |  1 +
 xtask/Cargo.toml   |  1 +
 xtask/src/local.rs | 32 ++++++++++++--------------------
 3 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 9704e406..99bf1efe 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5909,6 +5909,7 @@ name = "xtask"
 version = "0.7.0"
 dependencies = [
  "jiff",
+ "semver",
 ]
 
 [[package]]
diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
index 941b3d56..2a36b604 100644
--- a/xtask/Cargo.toml
+++ b/xtask/Cargo.toml
@@ -10,3 +10,4 @@ workspace = true
 
 [dependencies]
 jiff = { workspace = true }
+semver = { workspace = true }
diff --git a/xtask/src/local.rs b/xtask/src/local.rs
index c653978a..f655a116 100644
--- a/xtask/src/local.rs
+++ b/xtask/src/local.rs
@@ -514,38 +514,29 @@ fn rfc3339(secs: i64) -> String {
 
 // ---- versions -----------------------------------------------------------------------------------
 
-/// `1.2.3` or `1.2.3-pre.4`: the numeric core and the pre-release, if any.
-fn parse_version(v: &str) -> Option<([u64; 3], Option<String>)> {
-    let (core, pre) = match v.split_once('-') {
-        Some((c, p)) => (c, Some(p.to_string())),
-        None => (v, None),
-    };
-    let mut parts = core.split('.').map(|p| p.parse::<u64>().ok());
-    let n = [parts.next()??, parts.next()??, parts.next()??];
-    parts.next().is_none().then_some((n, pre))
+/// `1.2.3` or `1.2.3-pre.4`.
+fn parse_version(v: &str) -> Option<semver::Version> {
+    semver::Version::parse(v).ok()
 }
 
 /// The version a build of an unreleased commit gets: after `checkout` and before whatever is
 /// released next, ordered by commit time. `0.4.0` → `0.4.1-dev.20261010183500`;
 /// `1.0.0-rc.1` → `1.0.0-rc.1.dev.20261010183500`.
 fn dev_version(checkout: &str, committed: i64) -> Result<String, String> {
-    let ([major, minor, patch], pre) = parse_version(checkout).ok_or_else(|| format!("can't read version `{checkout}`"))?;
+    let v = parse_version(checkout).ok_or_else(|| format!("can't read version `{checkout}`"))?;
+    let (major, minor, patch) = (v.major, v.minor, v.patch);
     let stamp: String = rfc3339(committed).chars().filter(char::is_ascii_digit).collect();
-    Ok(match pre {
-        None => format!("{major}.{minor}.{}-dev.{stamp}", patch.checked_add(1).ok_or("version too large")?),
-        Some(pre) => format!("{major}.{minor}.{patch}-{pre}.dev.{stamp}"),
+    Ok(if v.pre.is_empty() {
+        format!("{major}.{minor}.{}-dev.{stamp}", patch.checked_add(1).ok_or("version too large")?)
+    } else {
+        format!("{major}.{minor}.{patch}-{}.dev.{stamp}", v.pre)
     })
 }
 
+/// Semver precedence: numeric pre-release parts compare as numbers (`rc.10` is after `rc.9`).
 fn compare_versions(a: &str, b: &str) -> std::cmp::Ordering {
-    use std::cmp::Ordering;
     match (parse_version(a), parse_version(b)) {
-        (Some((na, pa)), Some((nb, pb))) => na.cmp(&nb).then_with(|| match (pa, pb) {
-            (None, None) => Ordering::Equal,
-            (None, Some(_)) => Ordering::Greater,
-            (Some(_), None) => Ordering::Less,
-            (Some(x), Some(y)) => x.cmp(&y),
-        }),
+        (Some(x), Some(y)) => x.cmp_precedence(&y),
         _ => a.cmp(b),
     }
 }
@@ -734,6 +725,7 @@ mod tests {
         assert_eq!(rfc3339(i64::MIN), "-292277022657-01-27T08:29:52Z");
         assert_eq!(compare_versions("0.10.0", "0.9.0"), std::cmp::Ordering::Greater);
         assert_eq!(compare_versions("1.0.0", "1.0.0-rc.1"), std::cmp::Ordering::Greater);
+        assert_eq!(compare_versions("1.0.0-rc.10", "1.0.0-rc.9"), std::cmp::Ordering::Greater);
         assert!(parse_version("1.2").is_none() && parse_version(".building-1.2.3").is_none());
     }