Version 29.0 of the REST API includes an attribute for
picklistsForRecordTypein the response to
/sobjects/<object>/describe/layouts, but it appears to always be an empty array. Is there a way to enable this feature, or is it simply a placeholder for a future API version?
We have been using the SOAP API’s
describeLayoutcall to retrieve page layouts along with
picklistsForRecordTypemappings. Unfortunately, we have a customer org in which
describeLayoutreturns a 20MB (uncompressed) XML document for
Account, big enough to crash an iOS hybrid app using the Ajax Toolkit, so I’m eager to move to the REST API for page layouts and picklist option mappings.
This is now listed as a known issue: https://success.salesforce.com/issues_view?id=a1p30000000T2GwAAK