Trigger issue: If case.priority changes then contact .priority changes too

Question

trigger prioritycheck on Case (before insert, after update) {
    Set<ID> setacc = new  Set<ID>();
    for(case c : trigger.new){
        setacc.add(c.accountid);
    }
    Map<Id,List<Contact>> bottlemap = new Map<Id,List<Contact>>();
    List<Contact> tempList;

    for(case c : trigger.new){
        if(bottlemap != null && bottlemap.containskey(c.accountid)){
            tempList = bottlemap.get(c.accountid);
        }

        for( contact con: tempList){
            List<Contact> conList;
            conlist = new List<Contact>();
            conlist = bottlemap.get(c.accountid);
            if(c.priority == con.priority__c){
                c.contactid = con.id;
                break;
            }
        }
    }
}

Answer 1

Your question is a bit confusing but based on the comments you are trying to update all Contact records when a Cases priority changes.

The (untested) code below should achieve this or at least give you an idea of how to achieve it.

trigger prioritycheck on Case (after update) {
    if (Trigger.isUpdate) {
        Map<Id, String> accountIdToPriority = new Map<Id, String>();
        for (Case c : Trigger.new) {
            // Only fire when priority changes
            if (c.priority__c != Trigger.oldMap.get(c.Id).priority__c) { 
                accountIdToPriority.put(c.accountId, c.priority__c);
            }
        }
        List<Contact> contacts = [select AccountId 
                                  from Contact
                                  where AccountId in :accountIdToPriority.keySet()];

        for (Contact con : contacts) {
            con.priority__c = accountIdToPriority.get(con.AccountId);
        }
        if (contacts.size() > 0) {
            update contacts;
        }
    }
 }