fix: Set default ipfamilies to ipv4 if the field is empty (#9112)

Author: nilo19

pkg/provider/azure_utils.go

@@ -303,6 +303,9 @@ func getIPFamiliesEnabled(svc *v1.Service) (v4Enabled bool, v6Enabled bool) {
 			v6Enabled = true
 		}
 	}
+	if !v4Enabled && !v6Enabled {
+		v4Enabled = true
+	}
 	return
 }
 

pkg/provider/azure_utils_test.go

@@ -559,6 +559,14 @@ func TestGetIPFamiliesEnabled(t *testing.T) {
 			true,
 			false,
 		},
+		{
+			"IPv6",
+			&v1.Service{
+				Spec: v1.ServiceSpec{IPFamilies: []v1.IPFamily{v1.IPv6Protocol}},
+			},
+			false,
+			true,
+		},
 		{
 			"DualStack",
 			&v1.Service{
@@ -567,6 +575,54 @@ func TestGetIPFamiliesEnabled(t *testing.T) {
 			true,
 			true,
 		},
+		{
+			"DualStack IPv6 first",
+			&v1.Service{
+				Spec: v1.ServiceSpec{IPFamilies: []v1.IPFamily{v1.IPv6Protocol, v1.IPv4Protocol}},
+			},
+			true,
+			true,
+		},
+		{
+			"Empty IPFamilies - defaults to IPv4",
+			&v1.Service{
+				Spec: v1.ServiceSpec{IPFamilies: []v1.IPFamily{}},
+			},
+			true,
+			false,
+		},
+		{
+			"No IPFamilies field - defaults to IPv4",
+			&v1.Service{
+				Spec: v1.ServiceSpec{},
+			},
+			true,
+			false,
+		},
+		{
+			"Multiple IPv4 entries",
+			&v1.Service{
+				Spec: v1.ServiceSpec{IPFamilies: []v1.IPFamily{v1.IPv4Protocol, v1.IPv4Protocol}},
+			},
+			true,
+			false,
+		},
+		{
+			"Multiple IPv6 entries",
+			&v1.Service{
+				Spec: v1.ServiceSpec{IPFamilies: []v1.IPFamily{v1.IPv6Protocol, v1.IPv6Protocol}},
+			},
+			false,
+			true,
+		},
+		{
+			"Mixed multiple entries",
+			&v1.Service{
+				Spec: v1.ServiceSpec{IPFamilies: []v1.IPFamily{v1.IPv4Protocol, v1.IPv6Protocol, v1.IPv4Protocol}},
+			},
+			true,
+			true,
+		},
 	}
 	for _, tc := range testcases {
 		t.Run(tc.desc, func(t *testing.T) {