I was trying to use set.addAll method with a list of SObject, but I was not able to make it work. Is there any restriction with this data type?

Documentation doesn't mention any: Salesforce Set methods doc

List<String> myList = new List<String>{'Test1','Test2','Test3'};
System.debug(myList);
Set<String> mySet = new Set<String>();
Boolean areInserted = mySet.addAll(myList);
System.debug(areInserted);
System.debug(mySet);
System.debug('Check with SObjectType');
Schema.DescribeFieldResult productFieldResult = Schema.sObjectType.MyObject__c.fields.Product__c;
List<SObjectType> fieldResults = productFieldResult.getReferenceTo();
System.debug(fieldResults);
Set<SObjectType> fieldResultsSet = new Set<SObjectType>();
Boolean areInserted2 = fieldResultsSet.addAll(fieldResults);
System.debug(areInserted2);
System.debug(fieldResultsSet);
System.debug('Try with loop');
List<SObjectType> mySet2 = new List<SObjectType>();
for(SObjectType objType : fieldResults)
{
    mySet2.add(objType);
}
System.debug(mySet2);

Finds here the debug result.

Thanks, Agustina

Attribution to: Agustina García

Possible Suggestion/Solution #1

On the subject of whether contains works or not, I couldn't find a failing case with these simple tests (whether using standard or custom objects):

@isTest
private class SetTest {

    @isTest
    static void containsAndAddAll() {

        Set<SObjectType> s = new Set<SObjectType>{
                Contact.SObjectType,
                Account.SObjectType
                };
        assertContactAndAccountOnly(s);

        Set<SObjectType> ss = new Set<SObjectType>();
        ss.addAll(s);
        assertContactAndAccountOnly(ss);
    }

    private static void assertContactAndAccountOnly(Set<SObjectType> s) {

        System.assertEquals(false, s.contains(Task.SObjectType));
        System.assertEquals(true, s.contains(Contact.SObjectType));
        System.assertEquals(true, s.contains(Account.SObjectType));
        System.assertEquals(false, s.contains(Note.SObjectType));
        System.assertEquals(2, s.size());
    }

    @isTest
    static void addAndRemove() {

        Set<SObjectType> s = new Set<SObjectType>();

        // Add
        System.assertEquals(0, s.size());
        s.add(Note.SObjectType);
        System.assertEquals(1, s.size());
        s.add(Task.SObjectType);
        System.assertEquals(2, s.size());
        System.assertEquals(true, s.contains(Task.SObjectType));
        System.assertEquals(true, s.contains(Note.SObjectType));

        // Remove
        s.remove(Note.SObjectType);
        System.assertEquals(1, s.size());
        System.assertEquals(true, s.contains(Task.SObjectType));
        System.assertEquals(false, s.contains(Note.SObjectType));
        s.remove(Task.SObjectType);
        System.assertEquals(0, s.size());
        System.assertEquals(false, s.contains(Task.SObjectType));
        System.assertEquals(false, s.contains(Note.SObjectType));
    }
}

Attribution to: Keith C

Possible Suggestion/Solution #2

The problem you are seeing is that for some reason the string representation of Set and List when they contain SObjectType is wrong making it appear that they are empty. If you invoke other methods such as size or contains you will see the behaviour you expect. Your test hints at that by addAll returning true.

I'd call this behaviour a bug, but I don't think the string representation is documented anywhere...

A work around (to help with debugging) would be to write a utility method that builds the string representation by iterating over the content and appending to a string e.g.:

public class Util {
    public static String toString(Set<SObjectType> sobTypes) {
        return toString(new List<SObjectType>(sobTypes));
    }
    public static String toString(List<SObjectType> sobTypes) {
        // Note that String.join doesn't work here at present
        String s = '';
        for (SObjectType sobType : sobTypes) {
            if (s != '') {
                s += ', ';
            }
            s += sobType;
        }
        return '{' + s + '}';
    }
}

Attribution to: Keith C
This content is remixed from stackoverflow or stackexchange. Please visit https://salesforce.stackexchange.com/questions/31159