Ant deployment job fails: Cannot update a field to a Formula from something else

Question

We have two custom fields:

• Opportunity.PrimaryProduct__c(lookup onto CustomObject__c)
• Opportunity.ProductFamily__c(lookup onto CustomObject__c)

Any of them don't being referenced from any place in code etc, just used for integration purposes. But I need to make those fields cross-object formulas like:

• PrimaryProduct__r.ProductName__c
• PrimaryProduct__r.ProductFamily__c

Regarding integration layout I have to keep the same API names for fields, so I use DestructiveChanges.xml (pre deploy) to remove lookups and create formulas during deployment. It looks like that:

<types>
  <members>Opportunity.PrimaryProduct__c</members>
  <members>Opportunity.ProductFamily__c</members>
  <name>CustomField</name>
</types>

Deployment fails with the next error messages:

1. objects/Opportunity.object (Opportunity.PrimaryProduct__c) -- Error: Cannot update a filed to a Formula from something else
2. objects/Opportunity.object (Opportunity.ProductFamily__c) -- Error: Cannot update a filed to a Formula from something else

Please advice me how to convert fields from lookups to formulas.

Answer 1

It was my fault about running deployment with property checkOnly = true. This approach lets you just check if its possible to deploy your changes without actual deployment. In this case destructive changes make no impact on target org.