fflib_QueryFactory ListIndex out of bounds

[cropredyHelix]

Message:List index out of bounds: 0 
Stacktrace:Class.fflib_QueryFactory.getFieldPath: line 111, column 1
Class.fflib_QueryFactory.selectFields: line 234, column 1
Class.PermissionSetAssignmentsSelector.selectByUserIdAndPermissions: line 55, column 1

The relevant method where this fails is getFieldPath(..) shown below and line 111 is:

lastSObjectType = tokenDescribe.getReferenceTo()[0]; //if it's polymorphic doesn't matter which one we get

The use case where this happens is

• Selector on PermissionSetAssignment
• trying to resolve the field Assignee.Profile.Name and specifically the token ProfileId
• getReferenceTo() returns an empty list
• the running user does not possess profile Admin (most likely - does not possess View All Data)

Analysis

• fflib_SobjectDescribe.cls is V50 as is fflib_QueryFactory
• If the running user is Admin, the Describe returns a non-empty list for getReferenceTo()
• This appears to be another example (see also https://github.com/apex-enterprise-patterns/fflib-apex-common/issues/309 ) where the running user doesn't have describe visibility into a standard object through a standard relationship. But, if the selector is changed to use static or dynamic SOQL without using the QueryFactory, all is well.
• I'm not sure what you can do about this except trap for getReferenceTo() returning an empty list and throw an exception with a clue to the developer as to the workaround

private String getFieldPath(String fieldName){
    if(!fieldName.contains('.')){ //single field
        Schema.SObjectField token = fflib_SObjectDescribe.getDescribe(table).getField(fieldName.toLowerCase());
        if(token == null)
            throw new InvalidFieldException(fieldName,this.table);
        if (enforceFLS) 
            fflib_SecurityUtils.checkFieldIsReadable(this.table, token);    
        return token.getDescribe().getName();
    }

    //traversing FK relationship(s)
    List<String> fieldPath = new List<String>();
    Schema.SObjectType lastSObjectType = table;
    Iterator<String> i = fieldName.split('\\.').iterator();
    while(i.hasNext()){
        String field = i.next();
        Schema.SObjectField token = fflib_SObjectDescribe.getDescribe(lastSObjectType).getField(field.toLowerCase());
        DescribeFieldResult tokenDescribe = token != null ? token.getDescribe() : null;

        if (token != null && enforceFLS) {
            fflib_SecurityUtils.checkFieldIsReadable(lastSObjectType, token);
        }

        if(token != null && i.hasNext() && tokenDescribe.getSoapType() == Schema.SoapType.ID){
            lastSObjectType = tokenDescribe.getReferenceTo()[0]; //if it's polymorphic doesn't matter which one we get
            fieldPath.add(tokenDescribe.getRelationshipName());
        }else if(token != null && !i.hasNext()){
            fieldPath.add(tokenDescribe.getName());
        }else{
            if(token == null)
                throw new InvalidFieldException(field,lastSObjectType);
            else
                throw new NonReferenceFieldException(lastSObjectType+'.'+field+' is not a lookup or master-detail field but is used in a cross-object query field.');
        }
    }

        return String.join(fieldPath,'.');
    }

[wimvelzeboer]

Hi @cropredyHelix I think this issue was already discussed in this issue: https://github.com/apex-enterprise-patterns/fflib-apex-common/issues/233 And there is already an PR open with a fix: https://github.com/apex-enterprise-patterns/fflib-apex-common/pull/251

[cropredyHelix]

@wimvelzeboer - ah - so the fix is basically -- if there's no FLS to enforce, just bail out of the method right away. I should have thought of that as we don't enforce FLS in our enterprise org's selectors. Thanks !

[cropredyHelix]

hooray - V51.0 solves this @wimvelzeboer

VERSIONED BEHAVIOR CHANGE: From version 51.0 onwards, the getReferenceTo() method in the Schema.DescribeFieldResult class returns referenced objects that aren’t accessible to the context user. If the context user has access to an object’s field that references another object, irrespective of the context user’s access to the cross-referenced object, the DescribeFieldResult.getReferenceTo() method returns references. In version 50.0 and earlier, if the context user doesn’t have access to the cross-referenced object, the method returns an empty list.

[daveespo]

Per the previous comment on this ticket, we believe this is likely fixed with Spring '21 and #317 -- please reopen the issue if you disagree