Compare prerelease versions correctly for updates

src/bin/dosh-client.rs

@@ -4135,15 +4135,71 @@ fn update_binary_version_for_installer(local: &str, latest_tag: Option<&str>) ->
 }
 
 fn compare_dotted_versions(left: &str, right: &str) -> std::cmp::Ordering {
-    let left = parse_dotted_version(left);
-    let right = parse_dotted_version(right);
-    let width = left.len().max(right.len());
+    let left = parse_comparable_version(left);
+    let right = parse_comparable_version(right);
+    let width = left.core.len().max(right.core.len());
     for index in 0..width {
         let ordering = left
+            .core
             .get(index)
             .copied()
             .unwrap_or(0)
-            .cmp(&right.get(index).copied().unwrap_or(0));
+            .cmp(&right.core.get(index).copied().unwrap_or(0));
+        if ordering != std::cmp::Ordering::Equal {
+            return ordering;
+        }
+    }
+    compare_prerelease(left.prerelease.as_deref(), right.prerelease.as_deref())
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct ComparableVersion {
+    core: Vec<u64>,
+    prerelease: Option<String>,
+}
+
+fn parse_comparable_version(version: &str) -> ComparableVersion {
+    let version = version.strip_prefix('v').unwrap_or(version);
+    let version = version.split_once('+').map_or(version, |(base, _)| base);
+    let (core, prerelease) = version
+        .split_once('-')
+        .map_or((version, None), |(core, pre)| (core, Some(pre)));
+    ComparableVersion {
+        core: parse_dotted_version(core),
+        prerelease: prerelease
+            .filter(|value| !value.is_empty())
+            .map(|value| value.to_ascii_lowercase()),
+    }
+}
+
+fn compare_prerelease(left: Option<&str>, right: Option<&str>) -> std::cmp::Ordering {
+    match (left, right) {
+        (None, None) => std::cmp::Ordering::Equal,
+        (None, Some(_)) => std::cmp::Ordering::Greater,
+        (Some(_), None) => std::cmp::Ordering::Less,
+        (Some(left), Some(right)) => compare_prerelease_identifiers(left, right),
+    }
+}
+
+fn compare_prerelease_identifiers(left: &str, right: &str) -> std::cmp::Ordering {
+    let left_parts = left.split(['.', '-']).collect::<Vec<_>>();
+    let right_parts = right.split(['.', '-']).collect::<Vec<_>>();
+    let width = left_parts.len().max(right_parts.len());
+    for index in 0..width {
+        let Some(left) = left_parts.get(index).copied() else {
+            return std::cmp::Ordering::Less;
+        };
+        let Some(right) = right_parts.get(index).copied() else {
+            return std::cmp::Ordering::Greater;
+        };
+        let left_number = parse_numeric_identifier(left);
+        let right_number = parse_numeric_identifier(right);
+        let ordering = match (left_number, right_number) {
+            (Some(left), Some(right)) => left.cmp(&right),
+            (Some(_), None) => std::cmp::Ordering::Less,
+            (None, Some(_)) => std::cmp::Ordering::Greater,
+            (None, None) => left.cmp(right),
+        };
         if ordering != std::cmp::Ordering::Equal {
             return ordering;
         }
@@ -4151,6 +4207,12 @@ fn compare_dotted_versions(left: &str, right: &str) -> std::cmp::Ordering {
     std::cmp::Ordering::Equal
 }
 
+fn parse_numeric_identifier(value: &str) -> Option<u64> {
+    (!value.is_empty() && value.bytes().all(|byte| byte.is_ascii_digit()))
+        .then(|| value.parse::<u64>().ok())
+        .flatten()
+}
+
 fn parse_dotted_version(version: &str) -> Vec<u64> {
     version
         .split(|byte: char| !byte.is_ascii_digit())
@@ -11226,6 +11288,14 @@ mod tests {
             update_binary_version_for_installer("1.0.0-rc41", Some("v1.0.0-rc42")),
             None
         );
+        assert_eq!(
+            update_binary_version_for_installer("1.0.0", Some("v1.0.0-rc42")).as_deref(),
+            Some("v1.0.0")
+        );
+        assert_eq!(
+            update_binary_version_for_installer("1.0.0-rc42", Some("v1.0.0")),
+            None
+        );
         let config = ClientConfig::default();
         let unix = unix_update_script(
             &config,
@@ -11357,6 +11427,15 @@ mod tests {
             update_version_status("1.0.0-rc40", "1.0.0-rc37"),
             "local newer than latest release"
         );
+        assert_eq!(
+            update_version_status("1.0.0-rc42", "1.0.0"),
+            "update available"
+        );
+        assert_eq!(
+            update_version_status("1.0.0", "1.0.0-rc42"),
+            "local newer than latest release"
+        );
+        assert_eq!(update_version_status("1.0.0", "1.0.0+build.7"), "current");
     }
 
     #[test]