Getting System.ListException: Duplicate id in list:

Question

I am getting "System.ListException: Duplicate id in list: " in After trigger.How to prevent this.I am trying to update the same record after callout in after trigger.Below is my piece of code:

List<Patient_Package__c> lockPackage = new List<Patient_Package__c>();
if(trigger.new[index].Approval_Status__c=='Approved'){

            lockPackage.add(new Patient_Package__c( id=trigger.new[index].id,ECC_Sync_Status__c=label.PMM_ECC_STATUS_Processing));
            try{
            ECC_protocol_Sub_Callout.ecc_protocol_subscription(string.ValueOf(trigger.new[index].id));
            lockPackage.add(new Patient_Package__c( id=trigger.new[index].id,Approval_Status__c=''));
            }catch(exception e){
                PMM_Exception_DAO.insertExceptionRecord(e,'ECC_Onboarding_Callout','ecccallout');
                system.debug(e.getmessage());
            }
        }
        if(lockPackage!=null && !lockPackage.isEmpty()){
            update lockPackage;
        }

Answer 1

In your use case you can easily use map.

map<Id,Patient_Package__c> lockPackage = new map<Id, Patient_Package__c>();
if(trigger.new[index].Approval_Status__c=='Approved'){

            lockPackage.put(trigger.new[index].id,new Patient_Package__c( id=trigger.new[index].id,ECC_Sync_Status__c=label.PMM_ECC_STATUS_Processing));
            try{
            ECC_protocol_Sub_Callout.ecc_protocol_subscription(string.ValueOf(trigger.new[index].id));
            lockPackage.put(trigger.new[index].id,new Patient_Package__c( id=trigger.new[index].id,Approval_Status__c=''));
            }catch(exception e){
                PMM_Exception_DAO.insertExceptionRecord(e,'ECC_Onboarding_Callout','ecccallout');
                system.debug(e.getmessage());
            }
        }
        if( !lockPackage.isEmpty()){
            update lockPackage.values();
        }

This will remove your duplicate Id error.

PS As you are doing this in trigger then you should use before update and write your code there because in this way you need to handle recursive trigger error. And in before update you don't need DML.