chore: address review comments

Author: Regan Koopmans

packages/google-cloud-bigquery-storage/google/cloud/bigquery_storage_v1/schema.py

@@ -50,9 +50,6 @@
     types.TableFieldSchema.Type.JSON: descriptor_pb2.FieldDescriptorProto.TYPE_STRING,
     # INTERVAL is represented as a string
     types.TableFieldSchema.Type.INTERVAL: descriptor_pb2.FieldDescriptorProto.TYPE_STRING,
-    # STRUCT and RANGE use TYPE_MESSAGE and are handled specially
-    types.TableFieldSchema.Type.STRUCT: descriptor_pb2.FieldDescriptorProto.TYPE_MESSAGE,
-    types.TableFieldSchema.Type.RANGE: descriptor_pb2.FieldDescriptorProto.TYPE_MESSAGE,
 }
 
 
@@ -154,11 +151,11 @@ def _convert_bq_table_schema_to_proto_descriptor_impl(
     field_number = 1
 
     for bq_field in table_schema.fields:
-        # Sanitize the field name for use in scope
-        scope_name = _sanitize_field_name(bq_field.name)
-        current_scope = f"{scope}__{scope_name}"
-
         if bq_field.type_ == types.TableFieldSchema.Type.STRUCT:
+            # Sanitize the field name for use in scope
+            scope_name = _sanitize_field_name(bq_field.name)
+            current_scope = f"{scope}__{scope_name}"
+
             # Recursively convert nested struct
             nested_schema = types.TableSchema(fields=list(bq_field.fields))
             nested_descriptor, deeply_nested = _convert_bq_table_schema_to_proto_descriptor_impl(
@@ -172,6 +169,10 @@ def _convert_bq_table_schema_to_proto_descriptor_impl(
             fields.append(field)
 
         elif bq_field.type_ == types.TableFieldSchema.Type.RANGE:
+            # Sanitize the field name for use in scope
+            scope_name = _sanitize_field_name(bq_field.name)
+            current_scope = f"{scope}__{scope_name}"
+
             # Validate RANGE element type
             if not bq_field.range_element_type or not bq_field.range_element_type.type_:
                 raise ValueError(
@@ -217,7 +218,7 @@ def _convert_bq_table_schema_to_proto_descriptor_impl(
 
         else:
             # Primitive field
-            field = _convert_bq_field_to_proto_field(bq_field, field_number, current_scope)
+            field = _convert_bq_field_to_proto_field(bq_field, field_number, "")
             fields.append(field)
 
         field_number += 1