Better version comparison

crates/tower-cmd/src/lib.rs

@@ -85,8 +85,10 @@ impl App {
         if let Some(latest) = Self::check_latest_version().await {
             let current = tower_version::current_version();
 
-            if current != latest {
-                output::write_update_message(&latest, &current);
+            if tower_version::is_older_version(current, &latest) {
+                output::write_update_available_message(&latest, current);
+            } else if tower_version::is_newer_version(current, &latest) {
+                output::write_dev_version_message(current, &latest);
             }
         }
 

crates/tower-cmd/src/output.rs

@@ -501,7 +501,7 @@ pub fn spinner(msg: &str) -> Spinner {
     Spinner::new(msg.into())
 }
 
-pub fn write_update_message(latest: &str, current: &str) {
+pub fn write_update_available_message(latest: &str, current: &str) {
     let line = format!(
         "{}\n{}\n",
         format!(
@@ -517,6 +517,20 @@ pub fn write_update_message(latest: &str, current: &str) {
     io::stderr().write_all(line.as_bytes()).unwrap();
 }
 
+pub fn write_dev_version_message(current: &str, latest: &str) {
+    let line = format!(
+        "{}\n",
+        format!(
+            "Running dev version {} (latest published: {})",
+            current, latest
+        )
+        .dimmed()
+    );
+
+    use std::io::{self, Write};
+    io::stderr().write_all(line.as_bytes()).unwrap();
+}
+
 /// newline just outputs a newline. This is useful when you have a very specific formatting you
 /// want to maintain and you don't want to use println!.
 pub fn newline() {

crates/tower-version/src/lib.rs

@@ -42,3 +42,39 @@ pub async fn check_latest_version() -> Result<Option<String>> {
     }
     Ok(None)
 }
+
+fn parse_version(v: &str) -> Option<(u32, u32, u32)> {
+    let parts: Vec<_> = v.split('.').filter_map(|p| p.parse::<u32>().ok()).collect();
+    (parts.len() == 3).then(|| (parts[0], parts[1], parts[2]))
+}
+
+pub fn is_older_version(current: &str, latest: &str) -> bool {
+    matches!((parse_version(current), parse_version(latest)), (Some(c), Some(l)) if c < l)
+}
+
+pub fn is_newer_version(current: &str, latest: &str) -> bool {
+    matches!((parse_version(current), parse_version(latest)), (Some(c), Some(l)) if c > l)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_current_version_equal() {
+        assert!(!is_older_version("0.3.39", "0.3.39"));
+        assert!(!is_newer_version("0.3.39", "0.3.39"));
+    }
+
+    #[test]
+    fn test_older_version() {
+        assert!(is_older_version("0.3.38", "0.3.39"));
+        assert!(!is_newer_version("0.3.38", "0.3.39"));
+    }
+
+    #[test]
+    fn test_newer_version() {
+        assert!(!is_older_version("0.3.40", "0.3.39"));
+        assert!(is_newer_version("0.3.40", "0.3.39"));
+    }
+}