....and why should it matter?

TypeError: 'int' object has no attribute '__getitem__'

In fields.py, line 1197, in fnct_read value = value[field] or False

def _fnct_read(self, obj, cr, uid, ids, field_name, args, context=None):
    res = {}
    for record in obj.browse(cr, SUPERUSER_ID, ids, context=context):
        value = record
        for field in self.arg:
            if isinstance(value, list):
                value = value[0]
            value = value[field] or False
            if not value:
                break
        res[record.id] = value

So it wants the record.id and seems to be getting an int value. It's throwing an error even though it gets what it wants! Why wasn't this passed in the expected type? And why isn't there a case for the expected value to be int in the 1st place?

This is for a custom addon model which simply defines some columns.