Custom Metadata query - Metadata Relationship fields not supported

[gribis]

When custom metadata tables include references to related metadata (e.g. Entity or Field Definitions), fflib_QueryFactory throws an exception.

FeatureSetDefinition__mdt.ParentObject__r is not a lookup or master-detail field but is used in a cross-object query field.

The field definition for such a reference shows next to nothing of value; SoapType = String, isIdLookup = false, getRelationshipName = null.
Short of avoiding the selector/queryfactory constructs, what are some simple fixes to the above conundrum?

[wimvelzeboer]

@daveespo @stohn777 Is there already some update about this problem?
I ran into this issue again today. How do you advise we resolve this issue?

[daveespo]

@gribis or @wimvelzeboer -- can you provide a repro case (ideally a CMDT object definition and Selector class that reproduces this problem) ?

[edgk1]

repro steps:

1. create a new custom metadata object (Test__mdt)
2. entity definition field (Entity__c)
3. field definition field (Field__c) and select Entity as its controlling field
4. create a new custom metadata record, set Entity__c to custom object and Field__c to custom field
5. testSelector class:

public with sharing class TestSelector extends fflib_SObjectSelector {
	public TestSelector() {
		super(false, true, true, false);
	}

	public List<Schema.SObjectField> getSObjectFieldList() {
		return new List<Schema.SObjectField>{ Test__mdt.Id };
	}

	public Schema.SObjectType getSObjectType() {
		return Test__mdt.SObjectType;
	}

	public List<Test__mdt> selectAll() {

		fflib_QueryFactory qf = newQueryFactory();
		qf.selectFields(new List<String>{'Entity__r.QualifiedApiName', 'Field__r.QualifiedApiName'});

		return Database.query(qf.toSOQL());

	}
}

6. try to call the method: new TestSelector().selectAll();
7. exception thrown "fflib_QueryFactory.NonReferenceFieldException: Test__mdt.Entity__r is not a lookup or master-detail field but is used in a cross-object query field"

[DfdezRNV]

is this fixed somehow?