AddError on an object in a trigger is only displaying one of the errors in object list view

Question

I have a trigger on an object, and in that trigger I am doing the following:

List<ApexPages.Message> msgs = RecordValidator.isValidRecord(thisObj, criteria, matchingObjectUnionList.values());
if (!msgs.isEmpty()) {
    // add messages to page
    for (ApexPages.Message m : msgs) {
        system.debug(m.getDetail());
        thisDef.addError(m.getDetail());
    }
}

I have confirmed in my debug logs that two errors are found for blah 3 and blah each (see image below), so each of those gets two errors added through addError.

However, in the list view for my object when I try to update using inline edit, It gets the two errors according to debug logs, but when I click the red warning sign:

only one of the two is shown...

Is that a known issue with addError in lightning experience? Or how can I make sure it is displaying all errors it adds through addError?

Answer 1

It's a limitation of the addError interface. You are allowed at most one record-level error and one field level error per field. Adding a subsequent error will replace the original. This is also not a limit of Lightning, as you will experience the same behavior when using the API or the Classic UI. I don't think this is documented anywhere, but you should be aware of it. Unfortunately, since there's no way to dynamically select a field, you're going to have to come up with a way to add the error(s) to specific fields, or you might just want to join all the errors into a single string, then add them all at once.

if (!msgs.isEmpty()) {
    // add messages to page
    String[] messages = new String[0];
    for (ApexPages.Message m : msgs) {
        messages.add(m.getDetail());
    }
    thisDef.addError(String.join(messages,', '));
}