fix(ingest/powerbi): reduce type cast usage (datahub-project#12004)

Author: hsheth2

metadata-ingestion/src/datahub/ingestion/source/powerbi/m_query/data_classes.py

@@ -1,5 +1,4 @@
 import os
-from abc import ABC
 from dataclasses import dataclass
 from enum import Enum
 from typing import Any, Dict, List, Optional
@@ -12,18 +11,8 @@
 TRACE_POWERBI_MQUERY_PARSER = os.getenv("DATAHUB_TRACE_POWERBI_MQUERY_PARSER", False)
 
 
-class AbstractIdentifierAccessor(ABC):  # To pass lint
-    pass
-
-
-# @dataclass
-# class ItemSelector:
-#     items: Dict[str, Any]
-#     next: Optional[AbstractIdentifierAccessor]
-
-
 @dataclass
-class IdentifierAccessor(AbstractIdentifierAccessor):
+class IdentifierAccessor:
     """
     statement
         public_order_date = Source{[Schema="public",Item="order_date"]}[Data]
@@ -40,7 +29,7 @@ class IdentifierAccessor(AbstractIdentifierAccessor):
 
     identifier: str
     items: Dict[str, Any]
-    next: Optional[AbstractIdentifierAccessor]
+    next: Optional["IdentifierAccessor"]
 
 
 @dataclass

metadata-ingestion/src/datahub/ingestion/source/powerbi/m_query/pattern_handler.py

@@ -1,7 +1,7 @@
 import logging
 from abc import ABC, abstractmethod
 from enum import Enum
-from typing import Dict, List, Optional, Tuple, Type, Union, cast
+from typing import Dict, List, Optional, Tuple, Type, cast
 
 from lark import Tree
 
@@ -22,7 +22,6 @@
 )
 from datahub.ingestion.source.powerbi.m_query import native_sql_parser, tree_function
 from datahub.ingestion.source.powerbi.m_query.data_classes import (
-    AbstractIdentifierAccessor,
     DataAccessFunctionDetail,
     DataPlatformTable,
     FunctionName,
@@ -412,33 +411,25 @@ def create_lineage(
         )
         table_detail: Dict[str, str] = {}
         temp_accessor: Optional[
-            Union[IdentifierAccessor, AbstractIdentifierAccessor]
+            IdentifierAccessor
         ] = data_access_func_detail.identifier_accessor
 
         while temp_accessor:
-            if isinstance(temp_accessor, IdentifierAccessor):
-                # Condition to handle databricks M-query pattern where table, schema and database all are present in
-                # the same invoke statement
-                if all(
-                    element in temp_accessor.items
-                    for element in ["Item", "Schema", "Catalog"]
-                ):
-                    table_detail["Schema"] = temp_accessor.items["Schema"]
-                    table_detail["Table"] = temp_accessor.items["Item"]
-                else:
-                    table_detail[temp_accessor.items["Kind"]] = temp_accessor.items[
-                        "Name"
-                    ]
-
-                if temp_accessor.next is not None:
-                    temp_accessor = temp_accessor.next
-                else:
-                    break
+            # Condition to handle databricks M-query pattern where table, schema and database all are present in
+            # the same invoke statement
+            if all(
+                element in temp_accessor.items
+                for element in ["Item", "Schema", "Catalog"]
+            ):
+                table_detail["Schema"] = temp_accessor.items["Schema"]
+                table_detail["Table"] = temp_accessor.items["Item"]
             else:
-                logger.debug(
-                    "expecting instance to be IdentifierAccessor, please check if parsing is done properly"
-                )
-                return Lineage.empty()
+                table_detail[temp_accessor.items["Kind"]] = temp_accessor.items["Name"]
+
+            if temp_accessor.next is not None:
+                temp_accessor = temp_accessor.next
+            else:
+                break
 
         table_reference = self.create_reference_table(
             arg_list=data_access_func_detail.arg_list,
@@ -786,9 +777,10 @@ def get_db_name(self, data_access_tokens: List[str]) -> Optional[str]:
     def create_lineage(
         self, data_access_func_detail: DataAccessFunctionDetail
     ) -> Lineage:
-        t1: Tree = cast(
-            Tree, tree_function.first_arg_list_func(data_access_func_detail.arg_list)
+        t1: Optional[Tree] = tree_function.first_arg_list_func(
+            data_access_func_detail.arg_list
         )
+        assert t1 is not None
         flat_argument_list: List[Tree] = tree_function.flat_argument_list(t1)
 
         if len(flat_argument_list) != 2:

metadata-ingestion/src/datahub/ingestion/source/powerbi/m_query/resolver.py

@@ -1,6 +1,6 @@
 import logging
 from abc import ABC, abstractmethod
-from typing import Any, Dict, List, Optional, Tuple, Union, cast
+from typing import Any, Dict, List, Optional, Tuple, Union
 
 from lark import Tree
 
@@ -95,14 +95,12 @@ def get_item_selector_tokens(
         # remove whitespaces and quotes from token
         tokens: List[str] = tree_function.strip_char_from_list(
             tree_function.remove_whitespaces_from_list(
-                tree_function.token_values(
-                    cast(Tree, item_selector), parameters=self.parameters
-                )
+                tree_function.token_values(item_selector, parameters=self.parameters)
             ),
         )
         identifier: List[str] = tree_function.token_values(
-            cast(Tree, identifier_tree)
-        )  # type :ignore
+            identifier_tree, parameters={}
+        )
 
         # convert tokens to dict
         iterator = iter(tokens)
@@ -238,10 +236,10 @@ def _process_invoke_expression(
     def _process_item_selector_expression(
         self, rh_tree: Tree
     ) -> Tuple[Optional[str], Optional[Dict[str, str]]]:
-        new_identifier, key_vs_value = self.get_item_selector_tokens(  # type: ignore
-            cast(Tree, tree_function.first_expression_func(rh_tree))
-        )
+        first_expression: Optional[Tree] = tree_function.first_expression_func(rh_tree)
+        assert first_expression is not None
 
+        new_identifier, key_vs_value = self.get_item_selector_tokens(first_expression)
         return new_identifier, key_vs_value
 
     @staticmethod
@@ -327,7 +325,7 @@ def internal(
                 # The first argument can be a single table argument or list of table.
                 # For example Table.Combine({t1,t2},....), here first argument is list of table.
                 # Table.AddColumn(t1,....), here first argument is single table.
-                for token in cast(List[str], result):
+                for token in result:
                     internal(token, identifier_accessor)
 
             else:

metadata-ingestion/src/datahub/ingestion/source/powerbi/m_query/tree_function.py

@@ -1,6 +1,6 @@
 import logging
 from functools import partial
-from typing import Any, Dict, List, Optional, Union, cast
+from typing import Any, Dict, List, Optional, Union
 
 from lark import Token, Tree
 
@@ -58,7 +58,7 @@ def internal(node: Union[Tree, Token]) -> Optional[Tree]:
         if isinstance(node, Token):
             return None
 
-        for child in cast(Tree, node).children:
+        for child in node.children:
             child_node: Optional[Tree] = internal(child)
             if child_node is not None:
                 return child_node
@@ -99,7 +99,7 @@ def internal(node: Union[Tree, Token]) -> None:
                 logger.debug(f"Unable to resolve parameter reference to {ref}")
                 values.append(ref)
         elif isinstance(node, Token):
-            values.append(cast(Token, node).value)
+            values.append(node.value)
             return
         else:
             for child in node.children:

metadata-ingestion/src/datahub/ingestion/source/snowflake/snowflake_config.py

@@ -1,7 +1,7 @@
 import logging
 from collections import defaultdict
 from dataclasses import dataclass
-from typing import Dict, List, Optional, Set, cast
+from typing import Dict, List, Optional, Set
 
 import pydantic
 from pydantic import Field, SecretStr, root_validator, validator
@@ -118,9 +118,10 @@ def validate_legacy_schema_pattern(cls, values: Dict) -> Dict:
             )
 
         # Always exclude reporting metadata for INFORMATION_SCHEMA schema
-        if schema_pattern is not None and schema_pattern:
+        if schema_pattern:
             logger.debug("Adding deny for INFORMATION_SCHEMA to schema_pattern.")
-            cast(AllowDenyPattern, schema_pattern).deny.append(r".*INFORMATION_SCHEMA$")
+            assert isinstance(schema_pattern, AllowDenyPattern)
+            schema_pattern.deny.append(r".*INFORMATION_SCHEMA$")
 
         return values