I think I finished it...

crates/core/src/package.rs

@@ -19,8 +19,8 @@ pub struct PackageHandler {
 impl PackageHandler {
     const DIR_JAVA: &str = "java/";
 
-    pub fn new<P: AsRef<Path>>(package_root: P, target_dir: P) -> crate::Result<Self> {
-        let package_root = package_root.as_ref().to_path_buf();
+    pub fn new<P: AsRef<Path>>(src_dir: P, package_root: P, target_dir: P) -> crate::Result<Self> {
+        let package_root = src_dir.as_ref().join(package_root.as_ref());
 
         Ok(Self {
             prey: Prey::try_from(package_root.join(F_PREY_TOML))?,
@@ -42,32 +42,32 @@ impl PackageHandler {
         self.prey.version()
     }
 
-    pub fn get_update_targets(&mut self) -> crate::Result<Vec<&mut Class>> {
-        let mut targets = vec![];
-
+    pub fn get_update_targets(&mut self) -> crate::Result<Vec<&Class>> {
         if self.prey_lock.is_none() {
             // Try to pass a reference to the class so that there's mutability of the object
             // available at the workspace level instead of parsing all the way down the
             // tree. How I do this, idk. My brain is friend from a few days of JS.
 
-            self.prey_lock = Some(PreyLock::from(expand_files(Self::DIR_JAVA)?));
-            return Ok(self
-                .prey_lock
-                .clone()
-                .unwrap()
-                .classes
-                .iter()
-                .map(|mut *class| &mut class)
-                .collect());
+            self.prey_lock = Some(PreyLock::from(expand_files(
+                self.package_root.join(Self::DIR_JAVA),
+            )?));
+            return Ok(self.prey_lock.as_ref().unwrap().classes.iter().collect());
         }
 
-        for mut tracked in self.prey_lock.unwrap().classes {
-            if !tracked.is_updated()? {
-                targets.push(&mut tracked);
-            }
-        }
-
-        Ok(targets)
+        Ok(self
+            .prey_lock
+            .as_ref()
+            .unwrap()
+            .classes
+            .iter()
+            .filter_map(|tracked| {
+                if tracked.is_updated().is_ok_and(|v| v == true) {
+                    Some(tracked)
+                } else {
+                    None
+                }
+            })
+            .collect())
     }
 }