Refactoring/#221 fixed mypy warnings

doc/changes/changes_0.1.1.md

@@ -19,3 +19,4 @@ Code name:
 * #203: Cleaned-up package names and directory structure
 * #217: Rename dataflow abstraction files
 * #219: Applied PTB checks and fixes
+* #221: Fixed mypy warnings

exasol/analytics/query_handler/context/connection_name.py

@@ -6,10 +6,6 @@
 class ConnectionName(DBObjectName):
     """A DBObjectName class which represents the name of a connection object"""
 
-    @typechecked
-    def __init__(self, connection_name: str):
-        super().__init__(connection_name.upper())
-
 
 class ConnectionNameImpl(DBObjectNameImpl, ConnectionName):
 
@@ -19,4 +15,4 @@ def fully_qualified(self) -> str:
 
     @typechecked
     def __init__(self, connection_name: str):
-        super().__init__(connection_name)
+        super().__init__(connection_name.upper())

exasol/analytics/query_handler/context/proxy/db_object_name_with_schema_proxy.py

@@ -1,4 +1,4 @@
-from typing import Generic, TypeVar
+from typing import Generic, Optional, TypeVar
 
 from exasol.analytics.query_handler.context.proxy.db_object_name_proxy import (
     DBObjectNameProxy,
@@ -15,6 +15,6 @@ def __init__(self, db_object_name_with_schema: NameType, global_counter_value: i
         super().__init__(db_object_name_with_schema, global_counter_value)
 
     @property
-    def schema_name(self) -> SchemaName:
+    def schema_name(self) -> Optional[SchemaName]:
         self._check_if_released()
         return self._db_object_name.schema_name

exasol/analytics/query_handler/context/scope.py

@@ -62,5 +62,6 @@ def transfer_object_to(
         """
         pass
 
+    @abstractmethod
     def get_connection(self, name: str) -> Connection:
         pass

exasol/analytics/query_handler/deployment/aaf_exasol_lua_script_generator.py

@@ -32,7 +32,7 @@ def get_aaf_query_loop_lua_script_generator() -> ExasolLuaScriptGenerator:
     ]
     jinja_template_location = JinjaTemplateLocation(
         package_name=constants.BASE_PACKAGE,
-        package_path=constants.TEMPLATES_DIR,
+        package_path=str(constants.TEMPLATES_DIR),
         template_file_name=constants.LUA_SCRIPT_TEMPLATE,
     )
     generator = ExasolLuaScriptGenerator(

exasol/analytics/query_handler/deployment/lua_script_bundle.py

@@ -26,20 +26,19 @@ def __init__(
 
     def bundle_lua_scripts(self, output_buffer: IO):
         with tempfile.TemporaryDirectory() as tmp_dir:
-            tmp_dir = Path(tmp_dir)
-            self.copy_lua_source_files(tmp_dir)
-            self.run_lua_amlg(tmp_dir, output_buffer)
+            tmp_path = Path(tmp_dir)
+            self.copy_lua_source_files(tmp_path)
+            self.run_lua_amlg(tmp_path, output_buffer)
 
     def copy_lua_source_files(self, tmp_dir: Path):
         for src in self.lua_source_files + [self.lua_main_file]:
             dst = tmp_dir / src.name
             logger.debug(f"Copy {src} to {tmp_dir}")
-            shutil.copy(src, dst)
+            shutil.copy(str(src), dst)
 
     def run_lua_amlg(self, tmp_dir: Path, output_buffer: IO):
         output_file = tmp_dir / f"bundle_{time.time()}.lua"
         bash_command = "amalg.lua -o {out_path} -s {main_file} {modules}".format(
-            tmp_dir=tmp_dir,
             out_path=output_file,
             main_file=self.lua_main_file.name,
             modules=" ".join(self.lua_modules),

exasol/analytics/query_handler/deployment/utils.py

@@ -24,7 +24,7 @@ def get_password(pwd: str, user: str, env_var: str, descr: str) -> str:
 
 def load_and_render_statement(template_name, **kwargs) -> str:
     env = Environment(
-        loader=PackageLoader(constants.BASE_PACKAGE, constants.TEMPLATES_DIR),
+        loader=PackageLoader(constants.BASE_PACKAGE, str(constants.TEMPLATES_DIR)),
         autoescape=select_autoescape(),
     )
     template = env.get_template(template_name)

exasol/analytics/query_handler/graph/result.py

@@ -79,14 +79,14 @@ def __new__(cls, name: str, bases: Tuple[Type, ...], attrs: Any):
         """
         result_type = type(name, bases, attrs)
 
-        def _configured_new(cls: Type[cls]):
+        def _configured_new(cls: Type[_T]):
             """This function is called for subclasses of classes that declare _Meta as their metaclass."""
             return _new(cls, result_type)
 
-        result_type.__new__ = _configured_new
-        result_type.__init__ = _init
-        result_type.__setattr__ = _setattr
-        result_type.__delattr__ = _delattr
+        result_type.__new__ = _configured_new  # type: ignore
+        result_type.__init__ = _init  # type: ignore
+        result_type.__setattr__ = _setattr  # type: ignore
+        result_type.__delattr__ = _delattr  # type: ignore
         return result_type
 
 

exasol/analytics/query_handler/graph/stage/sql/execution/input.py

@@ -1,8 +1,6 @@
 import dataclasses
 
-from exasol_bucketfs_utils_python.abstract_bucketfs_location import (
-    AbstractBucketFSLocation,
-)
+import exasol.bucketfs as bfs
 
 from exasol.analytics.query_handler.graph.stage.sql.input_output import (
     SQLStageInputOutput,
@@ -13,5 +11,5 @@
 @dataclasses.dataclass(frozen=True, eq=True)
 class SQLStageGraphExecutionInput:
     input: SQLStageInputOutput
-    result_bucketfs_location: AbstractBucketFSLocation
+    result_bucketfs_location: bfs.path.PathLike
     sql_stage_graph: SQLStageGraph

exasol/analytics/query_handler/graph/stage/sql/execution/query_handler_state.py

@@ -21,6 +21,7 @@
 )
 from exasol.analytics.query_handler.query_handler import QueryHandler
 from exasol.analytics.query_handler.result import Continue, Finish
+from exasol.analytics.utils.errors import UninitializedAttributeError
 
 
 class ResultHandlerReturnValue(enum.Enum):
@@ -55,23 +56,38 @@ def __init__(
         self._current_query_handler: Optional[
             QueryHandler[List[SQLStageInputOutput], SQLStageInputOutput]
         ] = None
-        self._current_query_handler_context: Optional[ScopeQueryHandlerContext] = None
+        self._current_qh_context: Optional[ScopeQueryHandlerContext] = None
         self._create_current_query_handler()
 
-    def _check_is_valid(self):
-        if self._current_query_handler is None:
-            raise RuntimeError("No current query handler set.")
-
     def get_current_query_handler(
         self,
     ) -> QueryHandler[List[SQLStageInputOutput], SQLStageInputOutput]:
-        self._check_is_valid()
-        return self._current_query_handler
+        value = self._current_query_handler
+        if value is None:
+            raise RuntimeError("No current query handler set.")
+        return value
+
+    @property
+    def _checked_current_qh_context(self) -> ScopeQueryHandlerContext:
+        value = self._current_qh_context
+        if value is None:
+            raise UninitializedAttributeError(
+                "Current query handler context is undefined."
+            )
+        return value
+
+    @property
+    def _checked_current_stage(self) -> SQLStage:
+        value = self._current_stage
+        if value is None:
+            raise UninitializedAttributeError("Current stage is None.")
+        return value
 
     def handle_result(
         self, result: Union[Continue, Finish[SQLStageInputOutput]]
     ) -> ResultHandlerReturnValue:
-        self._check_is_valid()
+        # check if current query handler is set
+        self.get_current_query_handler()
         if isinstance(result, Finish):
             return self._handle_finished_result(result)
         elif isinstance(result, Continue):
@@ -90,7 +106,7 @@ def _handle_finished_result(
         return self._try_to_move_to_next_stage()
 
     def _try_to_move_to_next_stage(self) -> ResultHandlerReturnValue:
-        self._current_query_handler_context.release()
+        self._checked_current_qh_context.release()
         if self._is_not_last_stage():
             self._move_to_next_stage()
             return ResultHandlerReturnValue.CONTINUE_PROCESSING
@@ -101,7 +117,7 @@ def _try_to_move_to_next_stage(self) -> ResultHandlerReturnValue:
     def invalidate(self):
         self._current_stage = None
         self._current_query_handler = None
-        self._current_query_handler_context = None
+        self._current_qh_context = None
 
     def _is_not_last_stage(self):
         return self._current_stage_index < len(self._stages_in_execution_order) - 1
@@ -113,7 +129,7 @@ def _move_to_next_stage(self):
 
     def _create_current_query_handler(self):
         stage_inputs = self._stage_inputs_map[self._current_stage]
-        self._current_query_handler_context = (
+        self._current_qh_context = (
             self._query_handler_context.get_child_query_handler_context()
         )
         result_bucketfs_location = self._result_bucketfs_location.joinpath(
@@ -123,12 +139,12 @@ def _create_current_query_handler(self):
             result_bucketfs_location=result_bucketfs_location,
             sql_stage_inputs=stage_inputs,
         )
-        self._current_query_handler = self._current_stage.create_train_query_handler(
-            stage_input, self._current_query_handler_context
+        self._current_query_handler = self._checked_current_stage.create_train_query_handler(
+            stage_input, self._current_qh_context
         )
 
     def _add_result_to_successors(self, result: SQLStageInputOutput):
-        successors = self._sql_stage_graph.successors(self._current_stage)
+        successors = self._sql_stage_graph.successors(self._checked_current_stage)
         if len(successors) == 0:
             raise RuntimeError("Programming error")
         self._add_result_to_inputs_of_successors(result, successors)
@@ -146,7 +162,7 @@ def _add_result_to_reference_counting_bag(
         object_proxies = find_object_proxies(result)
         for object_proxy in object_proxies:
             if object_proxy not in self._reference_counting_bag:
-                self._current_query_handler_context.transfer_object_to(
+                self._checked_current_qh_context.transfer_object_to(
                     object_proxy, self._query_handler_context
                 )
             for _ in successors:
@@ -160,7 +176,7 @@ def _transfer_ownership_of_result_to_query_result_handler(self, result):
                     object_proxy
                 )
             else:
-                self._current_query_handler_context.transfer_object_to(
+                self._checked_current_qh_context.transfer_object_to(
                     object_proxy, self._query_handler_context
                 )
 

exasol/analytics/query_handler/python_query_handler_runner.py

@@ -17,6 +17,7 @@
 from exasol.analytics.query_handler.result import Continue, Finish
 from exasol.analytics.query_handler.udf.runner.state import QueryHandlerRunnerState
 from exasol.analytics.sql_executor.interface import SQLExecutor
+from exasol.analytics.utils.errors import UninitializedAttributeError
 
 LOGGER = logging.getLogger(__file__)
 
@@ -72,8 +73,8 @@ def _handle_continue(self, result: Continue) -> Union[Continue, Finish[ResultTyp
         self._cleanup_query_handler_context()
         self._execute_queries(result.query_list)
         input_query_result = self._run_input_query(result)
-        result = self._state.query_handler.handle_query_result(input_query_result)
-        return result
+        _result = self._state.query_handler.handle_query_result(input_query_result)
+        return _result
 
     def _run_input_query(self, result: Continue) -> PythonQueryResult:
         input_query_view, input_query = self._wrap_return_query(result.input_query)
@@ -116,24 +117,28 @@ def _release_and_create_query_handler_context_of_input_query(self):
     def _wrap_return_query(
         self, input_query: SelectQueryWithColumnDefinition
     ) -> Tuple[str, str]:
+        if self._state.input_query_query_handler_context is None:
+            raise UninitializedAttributeError(
+                "Current state's input query query handler context is not set."
+            )
         temporary_view_name = (
             self._state.input_query_query_handler_context.get_temporary_view_name()
         )
         input_query_create_view_string = cleandoc(
             f"""
-CREATE OR REPLACE VIEW {temporary_view_name.fully_qualified} AS
-{input_query.query_string};
-"""
+            CREATE OR REPLACE VIEW {temporary_view_name.fully_qualified} AS
+            {input_query.query_string};
+            """
         )
         full_qualified_columns = [
             col.name.fully_qualified for col in input_query.output_columns
         ]
         columns_str = ",\n".join(full_qualified_columns)
         input_query_string = cleandoc(
             f"""
-SELECT
-{textwrap.indent(columns_str, " " * 4)}
-FROM {temporary_view_name.fully_qualified};
-"""
+            SELECT
+            {textwrap.indent(columns_str, " " * 4)}
+            FROM {temporary_view_name.fully_qualified};
+            """
         )
         return input_query_create_view_string, input_query_string

exasol/analytics/query_handler/query/drop/view.py

@@ -12,5 +12,5 @@ def query_string(self) -> str:
         return f"DROP VIEW IF EXISTS {self._view_name.fully_qualified};"
 
     @property
-    def view_name(self) -> TableName:
+    def view_name(self) -> ViewName:
         return self._view_name

exasol/analytics/query_handler/query/result/python_query_result.py

@@ -47,15 +47,20 @@ def __init__(self, data: List[Tuple[Any, ...]], columns: List[Column]):
         }
         self._next()
 
+    def _range(self, num_rows: Union[int, str]) -> range:
+        if isinstance(num_rows, int):
+            return range(num_rows - 1)
+        if num_rows == "all":
+            return range(len(self._data) - 1)
+        raise ValueError(f'num_rows must be an int or str "all" but is {num_rows}')
+
     def fetch_as_dataframe(
         self, num_rows: Union[int, str], start_col=0
     ) -> Optional[pd.DataFrame]:
         batch_list = []
-        if num_rows == "all":
-            num_rows = len(self._data)
         if self._current_row is not None:
             batch_list.append(self._current_row)
-        for i in range(num_rows - 1):
+        for i in self._range(num_rows):
             self._next()
             if self._current_row is not None:
                 batch_list.append(self._current_row)

exasol/analytics/query_handler/query/result/udf_query_result.py

@@ -1,11 +1,19 @@
 import collections
-from typing import Any, Iterator, List, OrderedDict, Union
+from typing import Any, Iterator, List, Optional, OrderedDict, TYPE_CHECKING, Union
 
 from exasol.analytics.query_handler.query.result.interface import QueryResult, Row
 from exasol.analytics.schema.column import Column
 from exasol.analytics.schema.column_name import ColumnName
 from exasol.analytics.schema.column_type import ColumnType
 
+if TYPE_CHECKING:
+    # Importing pandas might take several seconds.  At runtime pandas is
+    # imported on-demand by UDF context.
+    #
+    # This file only imports pandas for type checking, see also
+    # https://legacy.python.org/dev/peps/pep-0484/#runtime-or-type-checking
+    import pandas
+
 
 class UDFQueryResult(QueryResult):
 
@@ -51,7 +59,10 @@ def rowcount(self) -> int:
 
     def fetch_as_dataframe(
         self, num_rows: Union[str, int], start_col: int = 0
-    ) -> "pandas.DataFrame":
+    ) -> Optional["pandas.DataFrame"]:
+        # This place intentionally uses a forward reference, to avoid
+        # importing pandas which might take several seconds, see comment at
+        # the beginning of the file.
         df = self._ctx.get_dataframe(num_rows, start_col=self._start_col)
         self._initialized = True
         if df is None:

exasol/analytics/query_handler/udf/runner/call_udf.py

@@ -1,6 +1,6 @@
 from exasol.analytics.query_handler.udf.runner.udf import QueryHandlerRunnerUDF
 
-udf = QueryHandlerRunnerUDF(exa)
+udf = QueryHandlerRunnerUDF(exa)  # type: ignore
 
 
 def run(ctx):

exasol/analytics/query_handler/udf/runner/state.py

@@ -14,6 +14,6 @@
 class QueryHandlerRunnerState:
     top_level_query_handler_context: TopLevelQueryHandlerContext
     query_handler: QueryHandler
-    connection_lookup: UDFConnectionLookup
+    connection_lookup: Optional[UDFConnectionLookup] = None
     input_query_query_handler_context: Optional[ScopeQueryHandlerContext] = None
     input_query_output_columns: Optional[List[Column]] = None