Contact trigger update error

Question

Trigger on contact It is giving the error ,please help me on this

Error:Apex trigger changestoProspectpendingEnrollment caused an unexpected exception, contact your administrator: changestoProspectpendingEnrollment: execution of BeforeUpdate caused by: System.DmlException: Update failed. First exception on row 0 with id a0hc0000006qTwsAAE; first error: SELF_REFERENCE_FROM_TRIGGER, Object (id = 003c000000YHLFG) is currently in trigger changestoProspectpendingEnrollment, therefore it cannot recursively update itself: []: Trigger.changestoProspectpendingEnrollment: line 66, column 1

trigger  changestoProspectpendingEnrollment on Contact (before update) {     

    for(contact con:trigger.new){

        if(con.Amount_MSRP__c != null && con.Payment_Plan__c != '' && con.RecordTypeId =='012E0000000R6UM' && con.Disposition_Code__c != ''){
            List<Transaction_Queue__c> trq =[select id,Status__c,Amount__c from Transaction_Queue__c where
                                             contact__c =:con.Id and Status__c ='Set to be Processed'];
            if(con.Charge_One_Time__c == true){ 
                if(con.Payment_Plan__c == 'Full pay' &&  con.Charge_One_Time_Amount__c == null){
                    con.Charge_One_Time_Amount__c = con.Amount_MSRP__c;
                }
                if(con.Payment_Plan__c == 'Full pay' &&  con.Charge_One_Time_Amount__c != null){
                    if(con.Charge_One_Time_Amount__c < con.Amount_MSRP__c ){
                        Trigger.new[0].Charge_One_Time_Amount__c.addError('Please Enter the amount not less than the scheduled amount');
                    }   
                }

                if(con.Payment_Plan__c == 'Semi-Annual' &&  con.Charge_One_Time_Amount__c == null){
                    con.Charge_One_Time_Amount__c = con.Amount_MSRP__c/2;  
                }
                if(con.Payment_Plan__c == 'Semi-Annual' &&  con.Charge_One_Time_Amount__c != null){
                    if(con.Charge_One_Time_Amount__c < con.Amount_MSRP__c/2 ){
                        Trigger.new[0].Charge_One_Time_Amount__c.addError('Please Enter the amount not less than the scheduled amount');
                    }
                }
                if(con.Payment_Plan__c == 'Quarterly' &&  con.Charge_One_Time_Amount__c == null){
                    con.Charge_One_Time_Amount__c = con.Amount_MSRP__c/4;  
                }
                if(con.Payment_Plan__c == 'Quarterly' &&  con.Charge_One_Time_Amount__c != null){
                    if(con.Charge_One_Time_Amount__c < con.Amount_MSRP__c/4 ){
                        Trigger.new[0].Charge_One_Time_Amount__c.addError('Please Enter the amount not less than the scheduled amount');
                    }  
                }
                if(con.Payment_Plan__c == 'Monthly' &&  con.Charge_One_Time_Amount__c == null){
                    con.Charge_One_Time_Amount__c = con.Amount_MSRP__c/12;  
                }
                if(con.Payment_Plan__c == 'Monthly' &&  con.Charge_One_Time_Amount__c != null){
                    if(con.Charge_One_Time_Amount__c < con.Amount_MSRP__c/12 ){
                        Trigger.new[0].Charge_One_Time_Amount__c.addError('Please Enter the amount not less than the scheduled amount');
                    } 
                }

                if(trq.isEmpty()==false){
                    for(Transaction_Queue__c t : trq){
                        t.Amount__c=math.abs(con.Charge_One_Time_Amount__c);
                    }
                    update trq;
                }

                if(trq.isEmpty()==true){
                    PayPageUtil.createTransactionque(con.Id, con.Default_Payment_Profile__c, 'Set to be Processed', Math.abs(con.Charge_One_Time_Amount__c));
                }
                con.AutoPay__c = false;
                con.Print_Invoice__c = true;

            }

            if(con.Charge_One_Time__c == false){
                con.Charge_One_Time_Amount__c = null;
                con.AutoPay__c = true;
                con.Print_Invoice__c = false; 
                if(trq.isEmpty()==false){
                    for(Transaction_Queue__c t : trq){
                        t.Status__c = 'Cancelled';
                    }
                    update trq;
                    break;
                }   

            }

        }
    } 
}

Answer 1

It seems like you are trying to update the same contact which has not yet been updated in the above trigger context. This might possibly be due to an apex trigger/workflow on Transaction_Queue__c object that tries to update related contact field.

So you need to ensure that both these actions happen in different transaction, also as I best practice whenever I perform DMLs , I go for after triggers and not before.