fix: skip IPAM init for empty IP annotation and handle nil IPRangeList (kubeovn#6296)

- Skip IPAM initialization when pod IP annotation is empty, log warning instead
- Make IPRangeList.Len() nil-safe to prevent panic in GetSubnetIPRangeString
- Add unit test for nil IPRangeList.Separate() behavior

Signed-off-by: zbb88888 <jmdxjsjgcxy@gmail.com>

Author: zbb88888

pkg/controller/init.go

@@ -452,9 +452,13 @@ func (c *Controller) InitIPAM() error {
 				portName := ovs.PodNameToPortName(podName, pod.Namespace, podNet.ProviderName)
 				ip := pod.Annotations[fmt.Sprintf(util.IPAddressAnnotationTemplate, podNet.ProviderName)]
 				mac := pod.Annotations[fmt.Sprintf(util.MacAddressAnnotationTemplate, podNet.ProviderName)]
+				if ip == "" {
+					klog.Warningf("pod %s/%s has empty IP annotation for provider %s, skip IPAM init", pod.Namespace, podName, podNet.ProviderName)
+					continue
+				}
 				_, _, _, err := c.ipam.GetStaticAddress(key, portName, ip, &mac, podNet.Subnet.Name, true)
 				if err != nil {
-					klog.Errorf("failed to init pod %s.%s address %s: %v", podName, pod.Namespace, pod.Annotations[fmt.Sprintf(util.IPAddressAnnotationTemplate, podNet.ProviderName)], err)
+					klog.Errorf("failed to init pod %s.%s address %s: %v", podName, pod.Namespace, ip, err)
 				} else {
 					err = c.createOrUpdateIPCR(portName, podName, ip, mac, podNet.Subnet.Name, pod.Namespace, pod.Spec.NodeName, podType)
 					if err != nil {

pkg/ipam/ip_range_list.go

@@ -77,6 +77,9 @@ func NewIPRangeListFrom(x ...string) (*IPRangeList, error) {
 }
 
 func (r *IPRangeList) Clone() *IPRangeList {
+	if r == nil {
+		return NewEmptyIPRangeList()
+	}
 	ret := &IPRangeList{make([]*IPRange, r.Len())}
 	for i := range r.ranges {
 		ret.ranges[i] = r.ranges[i].Clone()
@@ -85,10 +88,16 @@ func (r *IPRangeList) Clone() *IPRangeList {
 }
 
 func (r *IPRangeList) Len() int {
+	if r == nil {
+		return 0
+	}
 	return len(r.ranges)
 }
 
 func (r *IPRangeList) Count() internal.BigInt {
+	if r == nil {
+		return internal.BigInt{}
+	}
 	var count internal.BigInt
 	for _, v := range r.ranges {
 		count = count.Add(v.Count())
@@ -97,13 +106,16 @@ func (r *IPRangeList) Count() internal.BigInt {
 }
 
 func (r *IPRangeList) At(i int) *IPRange {
-	if i < len(r.ranges) {
-		return r.ranges[i]
+	if r == nil || i < 0 || i >= len(r.ranges) {
+		return nil
 	}
-	return nil
+	return r.ranges[i]
 }
 
 func (r *IPRangeList) Find(ip IP) (int, bool) {
+	if r == nil {
+		return 0, false
+	}
 	return sort.Find(len(r.ranges), func(i int) int {
 		if r.At(i).Start().GreaterThan(ip) {
 			return -1
@@ -121,6 +133,9 @@ func (r *IPRangeList) Contains(ip IP) bool {
 }
 
 func (r *IPRangeList) Add(ip IP) bool {
+	if r == nil {
+		return false
+	}
 	n, ok := r.Find(ip)
 	if ok {
 		return false
@@ -145,6 +160,9 @@ func (r *IPRangeList) Add(ip IP) bool {
 }
 
 func (r *IPRangeList) Remove(ip IP) bool {
+	if r == nil {
+		return false
+	}
 	n, ok := r.Find(ip)
 	if !ok {
 		return false

pkg/ipam/ip_range_list_test.go

@@ -1388,3 +1388,95 @@ func TestIPRangeListToCIDRsEdgeCases(t *testing.T) {
 		require.Equal(t, []string{"::/128"}, result)
 	})
 }
+
+func TestIPRangeList_NilReceiverSafety(t *testing.T) {
+	// Background: In single-stack subnets, V4Available or V6Available can be nil.
+	// All IPRangeList methods must handle nil receiver without panic.
+	var nilList *IPRangeList
+	ip, _ := NewIP("10.0.0.1")
+
+	t.Run("Len", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			require.Equal(t, 0, nilList.Len())
+		})
+	})
+
+	t.Run("Count", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			require.Equal(t, "0", nilList.Count().String())
+		})
+	})
+
+	t.Run("Clone", func(t *testing.T) {
+		var result *IPRangeList
+		require.NotPanics(t, func() {
+			result = nilList.Clone()
+		})
+		require.NotNil(t, result)
+		require.Equal(t, 0, result.Len())
+	})
+
+	t.Run("At", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			require.Nil(t, nilList.At(0))
+		})
+	})
+
+	t.Run("Find", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			idx, found := nilList.Find(ip)
+			require.Equal(t, 0, idx)
+			require.False(t, found)
+		})
+	})
+
+	t.Run("Contains", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			require.False(t, nilList.Contains(ip))
+		})
+	})
+
+	t.Run("Add", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			require.False(t, nilList.Add(ip))
+		})
+	})
+
+	t.Run("Remove", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			require.False(t, nilList.Remove(ip))
+		})
+	})
+
+	t.Run("Separate", func(t *testing.T) {
+		var result *IPRangeList
+		require.NotPanics(t, func() {
+			result = nilList.Separate(nil)
+		})
+		require.NotNil(t, result)
+		require.Equal(t, 0, result.Len())
+	})
+
+	t.Run("String", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			require.Equal(t, "", nilList.String())
+		})
+	})
+
+	t.Run("ToCIDRs", func(t *testing.T) {
+		require.NotPanics(t, func() {
+			cidrs, err := nilList.ToCIDRs()
+			require.NoError(t, err)
+			require.Nil(t, cidrs)
+		})
+	})
+}
+
+func TestIPRangeListSeparate_WithEmptyList(t *testing.T) {
+	// An empty but non-nil list returns empty result immediately without using 'other'
+	emptyList := NewEmptyIPRangeList()
+
+	result := emptyList.Separate(nil)
+	require.NotNil(t, result)
+	require.Equal(t, 0, result.Len())
+}