Assorted renames in column pruner classes (#1677)

This PR renames a few variables and methods in the column pruner classes
in preparation for #1679.

metricflow/sql/optimizer/column_pruning/column_pruner.py

@@ -32,10 +32,10 @@ def __init__(
         self,
         required_alias_mapping: NodeToColumnAliasMapping,
     ) -> None:
-        """Constructor.
+        """Initializer.
 
         Args:
-            required_alias_mapping: Describes columns aliases that should be kept / not pruned for each node.
+            required_alias_mapping: Describes columns aliases that should be retained for each node.
         """
         self._required_alias_mapping = required_alias_mapping
 
@@ -46,27 +46,33 @@ def visit_select_statement_node(self, node: SqlSelectStatementNode) -> SqlPlanNo
         required_column_aliases = self._required_alias_mapping.get_aliases(node)
         if required_column_aliases is None:
             logger.error(
-                f"Did not find {node.node_id=} in the required alias mapping. Returning the non-pruned version "
-                f"as it should be valid SQL, but this is a bug and should be investigated."
+                LazyFormat(
+                    "Did not find the given node in the required alias mapping. Returning the original version "
+                    "as it should be valid SQL, but this is a bug and should be investigated.",
+                    node_id=node.node_id,
+                )
             )
             return node
 
         if len(required_column_aliases) == 0:
             logger.error(
-                f"Got no required column aliases for {node}. Returning the non-pruned version as it should be valid "
-                f"SQL, but this is a bug and should be investigated."
+                LazyFormat(
+                    "Got no required column aliases the given node. Returning the original version as it should be valid "
+                    "SQL, but this is a bug and should be investigated.",
+                    node_id=node.node_id,
+                )
             )
             return node
 
-        pruned_select_columns = tuple(
+        retained_select_columns = tuple(
             select_column
             for select_column in node.select_columns
             if select_column.column_alias in required_column_aliases
         )
 
         return SqlSelectStatementNode.create(
             description=node.description,
-            select_columns=pruned_select_columns,
+            select_columns=retained_select_columns,
             from_source=node.from_source.accept(self),
             from_source_alias=node.from_source_alias,
             cte_sources=tuple(

metricflow/sql/optimizer/column_pruning/required_column_aliases.py

@@ -121,10 +121,10 @@ def _visit_parents(self, node: SqlPlanNode) -> None:
             parent_node.accept(self)
         return
 
-    def _tag_potential_cte_node(
+    def _map_required_column_aliases_in_potential_cte(
         self, cte_alias_mapping: SqlCteAliasMapping, table_name: str, column_aliases: Set[str]
     ) -> None:
-        """A reference to a SQL table might be a CTE. If so, tag the appropriate aliases in the CTEs."""
+        """A reference to a SQL table might be a CTE. If so, map the required column aliases in the CTEs."""
         cte_node = cte_alias_mapping.get_cte_node_for_alias(table_name)
 
         if cte_node is not None:
@@ -215,7 +215,7 @@ def visit_select_statement_node(self, node: SqlSelectStatementNode) -> None:
             )
             from_source_as_sql_table_node = node.from_source.as_sql_table_node
             if from_source_as_sql_table_node is not None:
-                self._tag_potential_cte_node(
+                self._map_required_column_aliases_in_potential_cte(
                     cte_alias_mapping=cte_alias_mapping,
                     table_name=from_source_as_sql_table_node.sql_table.table_name,
                     column_aliases=aliases_required_in_parent,
@@ -228,7 +228,7 @@ def visit_select_statement_node(self, node: SqlSelectStatementNode) -> None:
                 )
                 right_source_as_sql_table_node = join_desc.right_source.as_sql_table_node
                 if right_source_as_sql_table_node is not None:
-                    self._tag_potential_cte_node(
+                    self._map_required_column_aliases_in_potential_cte(
                         cte_alias_mapping=cte_alias_mapping,
                         table_name=right_source_as_sql_table_node.sql_table.table_name,
                         column_aliases=aliases_required_in_parent,
@@ -239,21 +239,21 @@ def visit_select_statement_node(self, node: SqlSelectStatementNode) -> None:
         for string_expr in exprs_used_in_this_node.string_exprs:
             if string_expr.used_columns:
                 for column_alias in string_expr.used_columns:
-                    for node_to_retain_all_columns in (node.from_source,) + tuple(
+                    for node_to_retain_columns in (node.from_source,) + tuple(
                         join_desc.right_source for join_desc in node.join_descs
                     ):
-                        self._current_required_column_alias_mapping.add_alias(node_to_retain_all_columns, column_alias)
+                        self._current_required_column_alias_mapping.add_alias(node_to_retain_columns, column_alias)
 
         # Same with unqualified column references - it's hard to tell which source it came from, so it's safest to say
         # it's required from all parents.
         # An unqualified column reference expression is like `SELECT col_0` whereas a qualified column reference
         # expression is like `SELECT table_0.col_0`.
         for unqualified_column_reference_expr in exprs_used_in_this_node.column_alias_reference_exprs:
             column_alias = unqualified_column_reference_expr.column_alias
-            for node_to_retain_all_columns in (node.from_source,) + tuple(
+            for node_to_retain_columns in (node.from_source,) + tuple(
                 join_desc.right_source for join_desc in node.join_descs
             ):
-                self._current_required_column_alias_mapping.add_alias(node_to_retain_all_columns, column_alias)
+                self._current_required_column_alias_mapping.add_alias(node_to_retain_columns, column_alias)
 
         # Visit recursively.
         self._visit_parents(node)