Bug: index out range when collaset spec.replicas < partition

[ColdsteelRail]

Minimal reproduce step

• 问题复现：Collaset缩容时，replicas值可能小于partion值，导致崩溃

apiVersion: apps.kusionstack.io/v1alpha1
kind: CollaSet
metadata:
  name: server
  namespace: operating-tutorial
spec:
  replicas: 2 # scale down from 3 to 2
  selector:
    matchLabels:
      app: server
  updateStrategy:
    podUpgradePolicy: InPlaceIfPossible
    rollingUpdate:
      byPartition:
        partition: 3
  template:
    metadata:
      labels:
        app: server
    spec:
      containers:
      - image: wu8685/echo:1.3
        name: server
        command:
        - /server
        resources:
          limits:
            cpu: "0.1"
            ephemeral-storage: 100Mi
            memory: 100Mi
          requests:
            cpu: "0.1"
            ephemeral-storage: 100Mi
            memory: 100Mi
        readinessProbe:
          httpGet:
            path: /healthz
            port: 8080
          initialDelaySeconds: 5
          periodSeconds: 3

What did you expect to see?

• 校验或拦截

What did you see instead

• kusionstack-controller-aneger崩溃

NAMESPACE            NAME                                              READY   STATUS    RESTARTS        AGE
kusionstack-system   kusionstack-controller-manager-6b6db85868-mgxc2   0/1     Error     8 (5m24s ago)   22m

• 关键日志

panic: runtime error: slice bounds out of range [:3] with capacity 2

goroutine 328 [running]:
kusionstack.io/operating/pkg/controllers/collaset/synccontrol.decidePodToUpdateByPartition(0xc000158a00, {0xc00094d8c0?, 0x1b78b80?, 0x2})
	/home/runner/work/operating/operating/pkg/controllers/collaset/synccontrol/update.go:108 +0xb2
kusionstack.io/operating/pkg/controllers/collaset/synccontrol.decidePodToUpdate(0xc00094d850?, {0xc00094d8c0?, 0x2?, 0xc00094c790?})
	/home/runner/work/operating/operating/pkg/controllers/collaset/synccontrol/update.go:85 +0x4f
kusionstack.io/operating/pkg/controllers/collaset/synccontrol.(*RealSyncControl).Update(0xc0003e7e80, 0xc000158a00, {0xc00094d850, 0x2, 0x2}, {0xc00094c790, 0x2, 0x2}, 0xc000108f20, 0xc000745800, ...)
	/home/runner/work/operating/operating/pkg/controllers/collaset/synccontrol/sync_control.go:358 +0x193
kusionstack.io/operating/pkg/controllers/collaset.(*CollaSetReconciler).doSync(0xc000324a40, 0x58?, 0x7f21f1aeb5b8?, {0xc00094c790, 0x2, 0x2}, 0x0?)
	/home/runner/work/operating/operating/pkg/controllers/collaset/collaset_controller.go:193 +0x1b5
kusionstack.io/operating/pkg/controllers/collaset.(*CollaSetReconciler).DoReconcile(0xc000339260?, 0x1b88c18?, 0xc000158a00?, {0xc00094c790?, 0x8?, 0xc000860350?}, 0x0?)
	/home/runner/work/operating/operating/pkg/controllers/collaset/collaset_controller.go:174 +0x2b
kusionstack.io/operating/pkg/controllers/collaset.(*CollaSetReconciler).Reconcile(0xc000324a40, {0x1b775b8, 0xc000652b10}, {{{0xc000846168?, 0x186e6a0?}, {0xc000860350?, 0x281b890?}}})
	/home/runner/work/operating/operating/pkg/controllers/collaset/collaset_controller.go:164 +0x63b
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile(0xc000000fa0, {0x1b775b8, 0xc000652ab0}, {{{0xc000846168?, 0x186e6a0?}, {0xc000860350?, 0xc000628380?}}})
	/home/runner/go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:114 +0x22c
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler(0xc000000fa0, {0x1b77510, 0xc0003165c0}, {0x174b160?, 0xc00080fb20?})
	/home/runner/go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:311 +0x2f2
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem(0xc000000fa0, {0x1b77510, 0xc0003165c0})
	/home/runner/go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:266 +0x1d9
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2()
	/home/runner/go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:227 +0x85
created by sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2
	/home/runner/go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:223 +0x30c

What is your KusionStack components and its version?

operating 版本: latest
Kubernetes 版本: v1.27.3

[ColdsteelRail]

thanks for your responses, could you please assign this issue to @ColdsteelRail, appreciate

[wu8685]

thanks for your responses, could you please assign this issue to @ColdsteelRail, appreciate

Assigned. Thanks for your contributing.