(core) Refactor Table.Record[Set] classes

Summary:
Dealing with some things that bothered and sometimes confused me:

Make Table.Record[Set] provide the table argument automatically
Remove the classes from UserTable because they're not used anywhere and the Table/UserTable distinction is already confusing. They're not documented for users and they don't show up in autocomplete.
Remove RecordSet.Record because it was confusing me where that attribute was being set, but also this means .Record will work properly for users with columns named 'Record'.

Test Plan: existing tests

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2913

sandbox/grist/table.py

@@ -61,14 +61,19 @@ class UserTable(object):
     self.Model = model_class
     column_ids = {col for col in model_class.__dict__ if not col.startswith("_")}
     column_ids.add('id')
-    self.Record = type('Record', (records.Record,), {})
-    self.RecordSet = type('RecordSet', (records.RecordSet,), {})
-    self.RecordSet.Record = self.Record
     self.table = None
 
   def _set_table_impl(self, table_impl):
     self.table = table_impl
 
+  @property
+  def Record(self):
+    return self.table.Record
+
+  @property
+  def RecordSet(self):
+    return self.table.RecordSet
+
   # Note these methods are named camelCase since they are a public interface exposed to formulas,
   # and we decided camelCase was a more user-friendly choice for user-facing functions.
   def lookupRecords(self, **field_value_pairs):
@@ -200,6 +205,18 @@ class Table(object):
     # For a summary table, the name of the special helper column auto-added to the source table.
     self._summary_helper_col_id = None
 
+    # Add Record and RecordSet subclasses which fill in this table as the first argument
+    class Record(records.Record):
+      def __init__(inner_self, *args, **kwargs):  # pylint: disable=no-self-argument
+        super(Record, inner_self).__init__(self, *args, **kwargs)
+
+    class RecordSet(records.RecordSet):
+      def __init__(inner_self, *args, **kwargs):  # pylint: disable=no-self-argument
+        super(RecordSet, inner_self).__init__(self, *args, **kwargs)
+
+    self.Record = Record
+    self.RecordSet = RecordSet
+
   def _rebuild_model(self, user_table):
     """
     Sets class-wide properties from a new Model class for the table (inner class within the table
@@ -207,8 +224,6 @@ class Table(object):
     """
     self.user_table = user_table
     self.Model = user_table.Model
-    self.Record = user_table.Record
-    self.RecordSet = user_table.RecordSet
 
     new_cols = collections.OrderedDict()
     new_cols['id'] = self._id_column
@@ -337,7 +352,7 @@ class Table(object):
       row_ids = sorted(row_id_set, key=lambda r: self._get_col_value(sort_by, r, rel))
     else:
       row_ids = sorted(row_id_set)
-    return self.RecordSet(self, row_ids, rel, group_by=kwargs, sort_by=sort_by)
+    return self.RecordSet(row_ids, rel, group_by=kwargs, sort_by=sort_by)
 
   def lookup_one_record(self, **kwargs):
     return self.lookup_records(**kwargs).get_one()
@@ -416,7 +431,7 @@ class Table(object):
     # user-actions caused by formula side-effects (e.g. as trigged by lookupOrAddDerived())
     if row_id not in self.row_ids:
       raise KeyError("'get_record' found no matching record")
-    return self.Record(self, row_id, None)
+    return self.Record(row_id, None)
 
   def filter_records(self, **kwargs):
     """
@@ -427,7 +442,7 @@ class Table(object):
     # See note in get_record() about using this call from formulas.
 
     for row_id in self.filter(**kwargs):
-      yield self.Record(self, row_id, None)
+      yield self.Record(row_id, None)
 
 
   # TODO: document everything here.