Try to work on build some more.

crates/core/src/dependency.rs

@@ -7,7 +7,8 @@ use crate::package::PackageHandler;
 #[derive(Debug, Clone, Deserialize, Serialize, Hash, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Dependency {
     name: String,
-    version: Version,
+    #[serde(skip_serializing_if = "<Option<_>>::is_none")]
+    version: Option<Version>,
     pub checksum: String,
     #[serde(skip_serializing_if = "<Option<_>>::is_none")]
     source: Option<String>, // Path / URL
@@ -24,13 +25,19 @@ impl Dependency {
         // TODO: Convert from reverse domain name to path.
         return self.name.clone();
     }
+
+    pub fn is_updated(&self) -> crate::Result<bool> {
+        // If the path is local and that file has not been updated.
+        Ok(self.source.as_ref().is_some_and(|path| is_url(path))
+            && self.checksum == sha256::try_digest(self.source.as_ref().unwrap())?)
+    }
 }
 
 impl From<PackageHandler> for Dependency {
     fn from(value: PackageHandler) -> Self {
         Dependency {
             name: value.name(),
-            version: value.version(),
+            version: Some(value.version()),
             checksum: String::new(),
             source: None,
         }