fix(scheduler): keep PodScheduled in cached pods (cherry-pick for v0.18.6-meshy.2)

.changes/unreleased/fixed-20261028-174735.yaml

@@ -0,0 +1,6 @@
+kind: Fixed
+body: |-
+  Scheduler patches a pending pod's PodScheduled condition only when it changes, not every cycle
+custom:
+  Author: "sam-huang1223"
+  Issue: "2544"

pkg/scheduler/cache/pod_transform.go

@@ -75,13 +75,16 @@ func compactContainerStatuses(statuses []v1.ContainerStatus) []v1.ContainerStatu
 	return compact
 }
 
+// compactConditions keeps PodResizePending for resize accounting and PodScheduled, which the status
+// updater compares against so it patches the condition only when it changes.
 func compactConditions(conditions []v1.PodCondition) []v1.PodCondition {
+	var compact []v1.PodCondition
 	for _, c := range conditions {
-		if c.Type == v1.PodResizePending {
-			return []v1.PodCondition{c}
+		if c.Type == v1.PodResizePending || c.Type == v1.PodScheduled {
+			compact = append(compact, c)
 		}
 	}
-	return nil
+	return compact
 }
 
 func compactContainers(containers []v1.Container) []v1.Container {

pkg/scheduler/cache/pod_transform_test.go

@@ -148,5 +148,25 @@ var _ = Describe("compactSchedulerPod", func() {
 			Expect(compact.Annotations).To(HaveLen(2))
 			Expect(compact.ManagedFields).To(BeNil())
 		})
+
+		It("keeps PodScheduled, which the status updater compares before patching it", func() {
+			pod := succeededPod()
+			pod.Status.Phase = v1.PodPending
+			unschedulable := v1.PodCondition{
+				Type:               v1.PodScheduled,
+				Status:             v1.ConditionFalse,
+				Reason:             v1.PodReasonUnschedulable,
+				Message:            "no nodes with enough resources",
+				LastTransitionTime: metav1.Unix(1767323045, 0),
+			}
+			resizePending := v1.PodCondition{Type: v1.PodResizePending, Status: v1.ConditionTrue}
+			pod.Status.Conditions = []v1.PodCondition{unschedulable, {Type: v1.PodReady}, resizePending}
+
+			transformed, err := compactSchedulerPod(pod)
+			Expect(err).NotTo(HaveOccurred())
+
+			compact := transformed.(*v1.Pod)
+			Expect(compact.Status.Conditions).To(Equal([]v1.PodCondition{unschedulable, resizePending}))
+		})
 	})
 })