Apply minor improvements

Author: reinterpretcat

vrp-core/src/construction/features/capacity.rs

@@ -230,7 +230,7 @@ where
     ) -> Option<ConstraintViolation> {
         let demand = self.get_demand(activity_ctx.target);
 
-        let violation = if activity_ctx.target.retrieve_job().is_some_and(|job| job.as_multi().is_some()) {
+        let violation = if activity_ctx.target.has_parent_job() {
             // NOTE multi job has dynamic demand which can go in another interval
             if self.can_handle_demand_on_intervals(route_ctx, demand, Some(activity_ctx.index)) {
                 None

vrp-core/src/models/problem/jobs.rs

@@ -197,6 +197,11 @@ impl Multi {
         single.dimens.get_value::<JobLink, Weak<Multi>>().and_then(|w| w.upgrade())
     }
 
+    /// Returns `true` if given single job is a child of multi job.
+    pub(crate) fn is_child(single: &Single) -> bool {
+        single.dimens.get_value::<JobLink, Weak<Multi>>().is_some()
+    }
+
     /// Wraps given multi job into [`Arc`] adding reference to it from all sub-jobs.
     fn bind(mut multi: Self) -> Arc<Self> {
         Arc::new_cyclic(|weak_multi| {

vrp-core/src/models/solution/route.rs

@@ -112,7 +112,18 @@ impl Activity {
 
     /// Checks whether activity has given job.
     pub fn has_same_job(&self, job: &Job) -> bool {
-        self.retrieve_job().as_ref() == Some(job)
+        match (job, self.job.as_ref()) {
+            (Job::Single(left), Some(right)) => Arc::ptr_eq(left, right),
+            (Job::Multi(multi), Some(single)) => {
+                Multi::roots(single).is_some_and(|single_parent| Arc::ptr_eq(multi, &single_parent))
+            }
+            _ => false,
+        }
+    }
+
+    /// Checks whether activity job has a parent multi job.
+    pub fn has_parent_job(&self) -> bool {
+        self.job.as_ref().map_or(false, |single| Multi::is_child(single))
     }
 
     /// Returns job if activity has it.