KB-2131 CDT fails to save with "The following types cannot be used, because they do not have a definition in the Appian data source" error

Symptoms

Saving the top level of a double nested CDT, similar to the example below, fails with the following error:

The following types cannot be used, because they do not have a definition in the Appian data source: [TopCDT (id=<ID>)]

A similar error message is also found in the application server log:

ERROR com.appiancorp.type.config.xsd.EcoreModelPersister - Error detected by Ecore save preview.
java.lang.IllegalArgumentException: The type {urn:com:appian:types}BottomCDT is referenced, but is not defined in the XSD.

Cause

This issue has been reported to the Appian Product Team. The reference number for this issue is AN-128273.

Workaround

Remove any field(s) referenced in the application server log error message and save the CDTs. In the error example above, the BottomCDT field would be removed from MiddleCDT.
Save the CDT referenced in the UI error. In the example above, TopCDT would be saved.
Add back the field(s) removed in step 1 and save the CDTs. Based on the example in step 1, add back the BottomCDT field in MiddleCDT.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: June 2020