Fix plugins versions being alpha compared

Signed-off-by: itowlson <[email protected]>

Author: itowlson

crates/plugins/src/manager.rs

@@ -12,6 +12,7 @@ use reqwest::{header::HeaderMap, Client};
 use serde::Serialize;
 use spin_common::sha256;
 use std::{
+    cmp::Ordering,
     fs::{self, File},
     io::{copy, Cursor},
     path::{Path, PathBuf},
@@ -173,7 +174,9 @@ impl PluginManager {
                     name: plugin_manifest.name(),
                     version: installed.version,
                 });
-            } else if installed.version > plugin_manifest.version && !allow_downgrades {
+            } else if installed.compare_versions(plugin_manifest) == Some(Ordering::Greater)
+                && !allow_downgrades
+            {
                 bail!(
                     "Newer version {} of plugin '{}' is already installed. To downgrade to version {}, run `spin plugins upgrade` with the `--downgrade` flag.",
                     installed.version,

crates/plugins/src/manifest.rs

@@ -70,6 +70,16 @@ impl PluginManifest {
     pub fn try_version(&self) -> Result<semver::Version, semver::Error> {
         semver::Version::parse(&self.version)
     }
+
+    // Compares the versions. Returns None if either's version string is invalid semver.
+    pub fn compare_versions(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        if let Ok(this_version) = self.try_version() {
+            if let Ok(other_version) = other.try_version() {
+                return Some(this_version.cmp_precedence(&other_version));
+            }
+        }
+        None
+    }
 }
 
 /// Describes compatibility and location of a plugin source.