Fix crash related to empty block in lb_vs resource

Empty block can be configured when no required attributes are
defined in the block. In this case nil protection is required,
since empty block is presented as nil rather than empty map in the
schema structure.

Signed-off-by: Anna Khmelnitsky <[email protected]>

nsxt/resource_nsxt_policy_lb_virtual_server.go

@@ -903,6 +903,10 @@ func getPolicyLbRuleVariablePersistenceLearnActionSchema() *schema.Schema {
 func getPolicyClientSSLBindingFromSchema(d *schema.ResourceData) *model.LBClientSslProfileBinding {
 	bindings := d.Get("client_ssl").([]interface{})
 	for _, binding := range bindings {
+		if binding == nil {
+			// empty clause
+			continue
+		}
 		// maximum count is one
 		data := binding.(map[string]interface{})
 		chainDepth := int64(data["certificate_chain_depth"].(int))
@@ -958,6 +962,10 @@ func setPolicyClientSSLBindingInSchema(d *schema.ResourceData, binding *model.LB
 func getPolicyServerSSLBindingFromSchema(d *schema.ResourceData) *model.LBServerSslProfileBinding {
 	bindings := d.Get("server_ssl").([]interface{})
 	for _, binding := range bindings {
+		if binding == nil {
+			// empty clause
+			continue
+		}
 		// maximum count is one
 		data := binding.(map[string]interface{})
 		chainDepth := int64(data["certificate_chain_depth"].(int))
@@ -1402,6 +1410,10 @@ func getPolicyLbRulesFromSchema(d *schema.ResourceData) []model.LBRule {
 	rules := d.Get("rule").([]interface{})
 
 	for _, rule := range rules {
+		if rule == nil {
+			// empty clause
+			continue
+		}
 		ruleData := rule.(map[string]interface{})
 
 		displayName := ruleData["display_name"].(string)
@@ -1412,6 +1424,10 @@ func getPolicyLbRulesFromSchema(d *schema.ResourceData) []model.LBRule {
 
 		ruleActions := ruleData["action"]
 		for _, ruleAction := range ruleActions.([]interface{}) {
+			if ruleAction == nil {
+				// empty clause
+				continue
+			}
 
 			ruleAction := ruleAction.(map[string]interface{})
 
@@ -1474,6 +1490,10 @@ func getPolicyLbRulesFromSchema(d *schema.ResourceData) []model.LBRule {
 
 		ruleConditions := ruleData["condition"]
 		for _, ruleCondition := range ruleConditions.([]interface{}) {
+			if ruleCondition == nil {
+				// empty clause
+				continue
+			}
 
 			ruleCondition := ruleCondition.(map[string]interface{})