PricebookEntry Conflict Error not matching existing products

Question

I am getting an error message on a trigger that was working until recently. The issue arises on a trigger that inserts an OpportunityLineItem on an Opportunity. Here is the error:

Insert failed. First exception on row 0; first error: FIELD_INTEGRITY_EXCEPTION, field integrity exception: unknown (pricebook entry is in a different pricebook than the one assigned to the opportunity):

Here is my confusion - I have a hard coded PriceBook Entry ID in the code (for now). But this id is drawn from the correct pricebook. To check myself, I was able to manually add an Opportunity Product and I display the Pricebook ID (via formula field). It is the same value. Any thoughts? Thanks

Answer 1

From the Product and Schedule Objects Data Model:

The PricebookEntry used by the OpportunityLineItem must have the same Pricebook2Id as the Opportunity.Pricebook2Id that you are adding it to.

E.g.

Id opportunityId = '006000000000001';
Id pricebookEntryId = '01u000000000001';

Opportunity opp = [Select Id, Pricebook2Id from Opportunity where Id = :opportunityId];
PricebookEntry pbe = [Select Id, Pricebook2Id from PricebookEntry where Id = :pricebookEntryId];
System.assertEquals(opp.Pricebook2Id, pbe.Pricebook2Id, 'OpportunityLineItem.PricebookEntry.Pricebook2Id should equal  OpportunityLineItem.Opportunity.Pricebook2Id');